- Mining Truck
- 794 AC (S/N: HRT1-UP)
- Off-Highway Truck/Tractor
- 794 AC (S/N: MN51-UP; MT51-UP)
- 796 (S/N: HRY1-UP; HRZ1-UP)
- 798 (S/N: ST71-UP)
- 796 (S/N: HRY1-UP; HRZ1-UP)
Reference: Operation and Maintenance Manual, SEBU9099, "794 AC Off-Highway Truck"
Reference: Service Magazine, SEPD1178, "Switch Settings for the Payload Monitors"
Reference: Service Manual, UENR3957, "794 AC Off-Highway TruckVIMS 3G and Truck Payload Measurement System (TPMS)"
Reference: Testing and Adjusting, UENR2267, "794 AC Off-Highway Truck Machine Systems"
Reference: Troubleshooting, UENR3890, "Electrical Shutdown and Voltage Discharge"
Reference: Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures"
Reference: Testing and Adjusting, UENR4125, "Air Conditioning and Heating R134a for All Cat Machines"
Introduction
Personal injury or death can result from air in the oil for the brake hydraulic system. Air in the system can prevent complete brake application and it is possible that the wheels on the machine can not be stopped. Air must not be in the oil for the brake hydraulic system to function properly. |
Personal injury or death can result from machine movement. Place blocks in front of and behind the wheels to make sure the machine does not move while the parking brakes are disengaged. |
Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks. |
Illustration 1 | g01962775 |
When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the body retaining pins. Install the body retaining pins through the ends of the retaining cables. Always use both retaining cables. Failure to properly secure the body (bed) may result in personal injury or death. |
When service or maintenance must be performed in a hazardous-voltage component enclosure, always assume that a hazardous level of voltage could be present. Qualified personnel should manually check for hazardous-voltage using electrical measuring tools that have the capacity to measure the hazardous-voltage components being checked. The level of voltage present must be confirmed to be below 50 VDC before any exposure to the hazardous-voltage components can take place. Failure to follow these instructions could result in personal injury or death. |
Working with electrical circuits is hazardous. Bodily contact with electrical potential will cause personal injury or death. Ensure that personnel are trained in proper operating procedures in order to ensure safe operation. |
The Power Train Electric Drive System will contain hazardous voltage levels during machine operation and for a short period of time after engine shutdown. Do not remove any covers that will expose energized high voltage electrical components while the engine is operating. Any type of maintenance on the following components can only be performed after the Power Train Electrical System Service Shutdown procedure has been followed:
Failure to follow these instructions could result in personal injury or death. |
In order to avoid the buildup of hazardous live voltages on the exposed surfaces, all grounding wires and grounding straps must be properly connected at all times during engine operation. Any disconnected grounding wires, including the grounding wires for all high voltage components and the grounding strap for the inverter cabinet must be properly reconnected before the engine is started. Failure to follow these instructions could result in personal injury or death. |
NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, PERJ1017, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
NOTICE |
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This machine is equipped with a Tier 4 Certified Engine system that is configured to meet the emissions requirements mandated by the United States Environmental Protection Agency (EPA). Care must be taken to comply with all instructions within this document to ensure that the engine, as assembled (including the exhaust piping, DEF Fluid lines, and controls), performs as designed to meet and maintain Tier 4 emissions requirements. Also, to meet the EPA regulatory requirements related to recording the combination of engine and emissions components that will be placed into service with the machine, perform the checks, and record the results as instructed in the "Emissions Compliance Report (Tier 4 Equipped Machines)" section later in this document. Complete and return the required information to the address listed in the "Emissions Compliance Report (Tier 4 Equipped Machines)" section later in the document. |
This Special Instruction contains the following necessary procedures for the 794 AC Off-Highway Truck commissioning procedure.
The photographs in this publication are for illustrative purposes. Do not perform any procedures in this publication or order any parts until you understand the information that is contained in this publication.
Dealer Information for Commissioning Procedure | |
---|---|
Date | |
Serial Number | |
Service Meter Units | |
Name of the Technician | |
Unit Number | |
Engine Serial Number | |
Pump Electronic Tank Unit (PETU) Serial Number(1) | |
Clean Emissions Module (CEM) Serial Number(1) | |
Dealer | |
Dealer Code | |
Customer | |
Job Site | |
Right-Hand Wheel Station Serial Number | |
Left-Hand Wheel Station Serial Number | |
Rear Axle Serial Number | |
Body Manufacturer/Part Number | |
Body Serial Number | |
General Body Condition |
(1) | If Tier 4 equipped |
Miscellaneous Checks | |
Take Digital Photos of Completed Truck | |
Missing Parts(1) | |
Performance Issues | |
Dealer Installed Attachments(2) | |
Dealer Comments(3) | |
Verify the function of all Cab Controls | |
Verify the function of the Engine Aftertreatment(4) | |
Payload Target |
(1) | Develop a list of all the part numbers and the next highest part number level. |
(2) | Take digital photos of all dealer installed attachments. |
(3) | Record positive and negative comments. |
(4) | If Tier 4 equipped |
Required Tooling
Illustration 2 | g02571852 |
Tooling (A) |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part No | Description |
A | Digital Pressure Indicator Gp | |||
A1 | 1 | Digital Indicator | ||
A2 | 1 | Pressure Sensor Gp
(0 kPa to 3,445 kPa (0 psi to 500 psi)) |
||
A2 | 1 | Pressure Sensor Gp
(0 kPa to 34,450 kPa (0 psi to 5,000 psi)) |
||
A2 | 1 | Pressure Sensor Gp
(0 kPa to 41,368 kPa (0 psi to 6,000 psi)) |
||
A2 | 1 | Pressure Sensor Gp
(0 kPa to 68,900 kPa (0 psi to 10,000 psi)) |
||
A3 | 1 | Adapter Cable As |
(1) | This sensor must be purchased separately, the sensor is not included in the |
(2) | This sensor can only be used on large diameter pressure taps like |
Illustration 3 | g02726620 |
Tooling (B) |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part No | Description |
B | B1 | 1 | Pressure Gauge
(-100 TO 500 kPa (-15 TO 72 psi)) |
|
B1 | 1 | Pressure Gauge
(0 TO 250 kPa (0 TO 36 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 400 kPa (0 TO 58 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 1,000 kPa (0 TO 144 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 4,000 kPa (0 TO 580 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 6,000 kPa (0 TO 860 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 10,000 kPa (0 TO 1,450 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 16,000 kPa (0 TO 2,300 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 25,000 kPa (0 TO 3,600 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 40,000 kPa (0 TO 5,800 psi)) |
||
B1 | 1 | Pressure Gauge
(0 TO 60,000 kPa (0 TO 8,600 psi)) |
||
B2 | 1 | Fitting | ||
B3 | 2 | Quick Connect Coupler | ||
B4 | 1 | Hose As
|
||
B4 | 1 | Hose As
|
||
B4 | 1 | Hose As
|
Illustration 4 | g03334430 |
Tooling (C) |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part
Number |
Description |
C | 1 | Communication Adapter Gp | ||
C1 | 1 | Cable As (USB PC Communication) | ||
C2 | 1 | Communication Adapter III | ||
C3 | 1 | Cable As (Data Link) |
(1) | Caterpillar Electronic Technician (Cat®ET) and Software CD, NETG5057 are required when using the communication adapter. |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part
Number |
Description |
T3 | T3a | 1 | Cap | |
T3b | 1 | Plug |
Illustration 5 | g06397839 |
Tooling (T4) |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part
Number |
Description |
T4 | T4a | 1 | O-Ring Seal | |
T4b | 1 | Adapter | ||
T4c | 2 | O-Ring Seal | ||
T4d | 1 | Elbow | ||
T4e | 1 | Fitting | ||
T4f | 1 | Dust Cap |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part
Number |
Description |
T5 | T5a | 1 | O-Ring Seal | |
T5b | 1 | — | 5/16-24 #2 STOR to
9/16-18 #6 STOR Adapter |
|
T5c | 2 | O-Ring Seal | ||
T5d | 1 | Fitting | ||
T5e | 1 | Dust Cap |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part
Number |
Description |
T6 | T6a | 1 | O-Ring Seal | |
T6b | 1 | Adapter | ||
T6c | 2 | O-Ring Seal | ||
T6d | 1 | Elbow | ||
T6e | 1 | Fitting | ||
T6f | 1 | Dust Cap |
Required Tools | ||||
---|---|---|---|---|
Tool | Item | Qty | Part
Number |
Description |
T7 | T7a | 1 | O-Ring Seal | |
T7b | 1 | Adapter | ||
T7c | 2 | Sampling Valve | ||
T7d | 1 | Dust Cap |
Perform the Commissioning Procedure for the Machine
Reference: Refer to Operations and Maintenance Manual, SEBU9099, "794 AC Off-Highway Truck" for additional information on the oil recommendations.
Reference: Refer to Testing and Adjusting, UENR2267, "794 AC Off-Highway Truck Machine Systems" for hydraulic check information.
Illustration 6 | g01340699 |
Note: Ensure that the wheels are chocked before performing the commissioning procedure.
Fluid Level Checks
Reference: Refer to Operations and Maintenance Manual, SEBU9099, Capacities (Refill) for additional information on checking the fluid levels.
Checking the Fluid Levels | Check if OK |
---|---|
Engine Coolant System(1) | |
Hydraulic Tank | |
Engine Crankcase | |
Left Rear Final Drive | |
Right Rear Final Drive | |
Grease for the Autolube | |
Left Front Wheel Station | |
Right Front Wheel Station | |
Window Washer Reservoir | |
Fuel | |
Diesel Exhaust Fluid (DEF)(2) |
(1) | Check the Jacket Water level. |
(2) | If Tier 4 Equipped |
Ground Straps
- Inspect ground straps. Ensure that all ground straps are present, secure, and have a good electrical connection.
Note: Paint under a ground strap at the mounting location, can cause poor electrical connection.
Show/hide tableTable 12 Location of Ground Straps Check if OK Ground Strap Location G1 Generator Right side of the generator to Right- Hand frame rail.(1) G2 Engine Right rear engine mount to Right-Hand frame rail.(1) G3 Upper Cooler Left-Hand side of cooler to inside of Left-Hand frame rail.(1) G4 Radiator Group Left-Hand bottom of cooler to Left-Hand cooler mount.(1) G5 Superstructure Left-Hand rear superstructure saddle mount to Left-Hand frame rail.(1) G6 Rear Axle Housing Top of rear axle housing front center linkage to frame near cross tube.(1) G7 RH Drive Motor Inside the rear axle housing.(2) G8 LH Drive Motor Inside the rear axle housing.(2) G9 Cab Right front corner under the cover.(2) G10 Upper Upright Beam Top box to Left-Hand upright beam.(2) G11 Lower Upright Beam Lower box to Left-Hand upright beam(2) G12 ECM Cabinet Bottom of ECM cabinet to the deck.(2) G13 Retarding Grid Inboard side of the retarding grid to the deck.(2) G14 Inverter Cabinet Two cables at the Right rear of the inverter cabinet by cable entry.(2) Show/hide table(1) Refer to Illustration 7 (2) Refer to Illustration 8
Illustration 7 | g06286455 |
Ground strap locations |
Illustration 8 | g06322401 |
Ground strap locations |
Pins and Retainers
Illustration 9 | g06323429 |
Examples of pins, retainers, and hardware |
Inspect machine pins, retainers, and hardware.
Pins, Retainers, and Hardware | ||
---|---|---|
Inspection Area | Left-Hand Side | Right-Hand Side |
Platform Connections | ||
Front Suspension Cylinders | ||
Front Axle Connections | ||
Steering Linkages | ||
Hoist Cylinders | ||
Rear Axle Housing Nosecone Bushing | ||
Rear Axle Housing Rear Linkage | ||
Rear Suspension Cylinders | ||
Rear Dump Body Pins |
High-Voltage Cabling
- Inspect all the high-voltage cabling for the proper routing and for any interference.
Look for issues such as the following:
- Any area where the cabling may rub on other components or other cables
- Improperly secured cables or loose cables
- Bent, kinked, or twisted cables
- Cut, nicked or damaged cables
High-Voltage System Megger Test
- Ensure that the electrical system is discharged.
Reference: Troubleshooting, UENR3890, "Electrical Shutdown and Voltage Discharge"
- Turn off the main disconnect.
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Illustration 10 g06402940 - Remove covers (A).
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Illustration 11 g02913001 View of the rear side of the inverter cabinet - Remove cover (B).
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Illustration 12 g06404197 View of inverter cabinet back
(C) Retarding Grid Blower Inverter - Remove the four internal ground wires at the bottom left-hand area of compartment behind cover (B). Isolate each of the ground wires from one another. Isolate each of the ground wires from the frame ground.
Note: The test must hold a minimum of two meg ohms.
- Remove "IP" and "IN" from the top of the Retarding Grid Blower Inverter (RGBI) (C) per Illustration 12.
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Illustration 13 g02160914 - Open the contractor compartment and connect a jumper between the "DCP" and the "DCN" bus bars.
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Illustration 14 g02160915 - In the contractor compartment, using the 2500 V setting, megger the "DCP" or the "DCN" to ground. Connect the positive to "DCP" or the "DCN" and connect to the negative to the location in Illustration 14.
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Illustration 15 g02160916 - In the contractor compartment, using the 2500 V setting, megger the "CNP" or the "CNN" to ground. Leave the ground in the previous location. The reading should be 2 megaohms or greater of resistance to ground.
Note: "IP" and "IN" must be disconnected from RGBI (C) for correct reading.
Show/hide tableIllustration 16 g02161299 View of the motor 1 connection - Open the "HV" cable connection compartment. Individually megger each phase of the "motor 1" cable using the 2500 V setting . The reading should be 2 megaohms or greater of resistance to ground.
Note: Only necessary to megger each phase, if the motor is not connected. When motor is connected one phase is enough. The connected motor makes the connection between the phases while testing.
Show/hide tableIllustration 17 g02161435 View of the generator connection - Individually megger each phase of the "generator" cable to ground using the 2500 V setting . The reading should be 2 megaohms or greater of resistance to ground.
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Illustration 18 g02161331 View of the motor 2 connection - Individually megger each phase of the "motor 2" cable to ground using the 2500 V setting one phase. The reading should be 2 megaohms or greater of resistance to ground.
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Illustration 19 g06403425 View of the three blower motor cable termination location.
(C) Retarding Grid Blower Inverter - Access the grid blower motor AC three phase connections at there termination location at rear of inverter cabinet to the bottom of the RGBI (C) per Illustration 19. Change test setting to 1000 V. Individually megger each phase of the three blower motor cables to ground at 1000 V setting.
Reference: Refer to Service Manual, UENR3890, "Troubleshooting 794 AC Off-Highway Truck" to troubleshoot the electrical system.
- If the system meggers ok, remove the tool, remove the jumper wire, restore the intentional ground wire, and restore the disconnected RGBI wires.
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Illustration 20 g06402940 - Install covers (A) onto the inverter cabinet.
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Illustration 21 g03788807 - Install cover (B) onto the inverter cabinet.
Check the Configuration of the Electronic Control Modules (ECM)
- Turn on the electrical system power
- Disengage the battery disconnect switch (4). The light will be OFF.
- In the cab, turn the key to the ON position.
Note: The gauges should illuminate all icons and all gauges will swing from full left to full right and return to full left. Advisor should flash red, yellow, and green.
Show/hide tableIllustration 22 g03741877 (4) Battery disconnect switch Show/hide tableIllustration 23 g06285963 (1) "VIMS" connector
(2) "CAT ET" connector
(3) 12 V connector - Connect a laptop computer to the Caterpillar Diagnostic Connector on the right-hand side of the center counsel.
- To power the electrical system of the truck, perform the steps that follow:
- Use your laptop computer to open Caterpillar Electronic Technician. Use the latest version of Caterpillar Electronic Technician.
Note: The Illustrations that are shown using Caterpillar Electronic Technician are for reference only. Use the latest version of Caterpillar Electronic Technician.
Show/hide tableIllustration 24 g06299836 - Verify the machine serial number in the "Product ID" parameter under the "Monitor 794 AC" ECM.
- Update each parameter under each ECM configuration to meet the site-specific requirements. The ECM configurations are shown in Illustration 24
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Illustration 25 g06299907 Note: The "Equipment ID" will need to be set up in each ECM.
- From the toolbar, select "Service", and select "Configuration".
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Illustration 26 g06299920 - From the toolbar, select "Service". Then select "ECM Date/Time".
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Illustration 27 g03868228 - Input the correct time zone, the date, and the time.
Enable Hoist
- Enable the hoist under the "Chassis 794" ECM.
Illustration 28 | g06299934 |
Set Machine Speed Correction Factor
Speed Correction Factor | ||
---|---|---|
Tire Size | Manufacturer | Correction Factor |
59/80 R63 | Bridgstone | 2.9804 |
55/80 R63 | Bridgstone | 0(1) |
56/80 R63 | Michelin | 2.742 |
53/80 R63 | Michelin | 1.2938 |
59/80 R63 | Goodyear | 4.3584 |
(1) | Default |
- Set the machine speed correction factor under the "Drivetrain 794" ECM.
Illustration 29 | g06299956 |
Injector Code Setting and Calibration
- From the toolbar, click "Service". Select "Calibrations". Click "Injector Trim Calibration".
- Confirm that all the injectors have trim files.
Illustration 30 | g03868243 |
VIMS
- Using SIS Web, locate the VIMS Main flash file, VIMS Application flash file, VIMS Main configuration file, and VIMS Application file for your specific Serial Number. Save each file to a local hard drive.
- Using SIS Web locate the VIMS Wash Configuration File (380-3140.cfg). Save this file to a local hard drive
Note: Do not change the name of the files when saving to the local hard drive.
- Connect the VIMSpc download cable ( 305-5528 Cable As) to the service port cable (1) in the cab port on the machine.
- Connect the Ethernet cable portion of the VIMSpc download cable ( 305-5528 Cable As) to the back of a laptop that is equipped with VIMSpc 2011A.
Note: The bumper port must be used on machines equipped with MineStar
Show/hide tableIllustration 32 g02720794 (1) "Connect" button - Launch VIMSpc 2011A from the shortcut on your desktop or through the start menu.
- Click the "Connect" button (1) that is on the left side of the VIMSpc application screen.
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Illustration 33 g02720798 - Select the appropriate port where the connection is being attempted. Select "Cab" for the cab port or "Chassis" for the bumper port. Then click the "OK" button
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Illustration 34 g02720801 (2) "Connection Icon" - Verify that a connection to the VIMS has been established. The connection to the VIMSpc is established once the "Connection Icon" (2) at the bottom left hand of the screen turns from red to green.
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Illustration 35 g02738858 (3) Check box for "Enable resetting cumulative and histogram after download" - Select the "Settings" button on the left-hand menu, and check the box for "Enable resetting cumulative and histogram after download" (3).
Note: This option is active for only one download. Restart VIMSpc to reset this feature.
Show/hide tableIllustration 36 g02738956 (4) Box at the top of the column to the left of the "Type" column
(5) Checkboxes in the "Reset" column - Select "Download" from the left-hand menu. Select the menu item listed as "All" in the "Download Groups Section". Select the box at the top of the column to the left of the "Type" column (4). Selecting the box at the top of the column to the left of the "Type" column will then allow the selection of all the checkboxes in the "Reset" column (5).
Note: This process will clear the stored VIMS data on the VIMS ECMs, so the database will know that the data is reset. Clearing this data will show a "reset" point in the database for this machine.
Show/hide tableIllustration 37 g02753117 (7) "Download" button - Select the "Download" button (7) on the bottom of the screen. The resulting files should be forwarded to the person managing the data.
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Illustration 38 g02936096 - From the toolbar, click "Configure Equipment" tab and verify that the serial number in the "Onboard" column matches the new serial number in the "User Specified" column.
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Illustration 39 g02936596 - In the "Equipment Number" field under the "User Specified" column, change the equipment number to correspond to the new customer machine number.
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Illustration 40 g02936521 - Enter the date and time in the "Date/Time" field under the "User Specified" column.
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Illustration 41 g02936378 - Click the "Update" button.
Note: The "SMH" is not resettable.
Note: Refer to Service Manual, UENR3957, "794 AC Off-Highway TruckVIMS 3G and Truck Payload Measurement System (TPMS)" for additional information on warnings.
Note: Refer to Special Instruction, REHS7412, "VIMS 3GSoftware Installation Guide For Large Off-Highway Truck (LOHT) Using VIMSpc 2011A" information for installation of the VIMS 3G software using VIMSpc 2011A and Cat ET (Version 2010B-v1.0 or newer).
Note: The following screen shots in the Illustrations are for visual reference only. The file-specific information on the Illustrations may differ from the information being displayed on the machine being serviced. Always refer to SIS Web for the latest flash files for the machine being serviced and program updates for the program being used.
Illustration 31 | g06285963 |
(1) "VIMS" connector
(2) "CAT ET" connector (3) 12 V connector |
Preliminary Set-Up Prior to Starting the Engine
Note: Refer to Operation and Maintenance Manual, SEBU9099, "794 AC" for additional information on starting the machine.
When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the body retaining pins. Install the body retaining pins through the ends of the retaining cables. Always use both retaining cables. Failure to properly secure the body (bed) may result in personal injury or death. |
Pre-startup Checks
- Verify function of warning lights and systems.
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Illustration 43 g06400541 Accumulator locations
(17) Brake Accumulators
(18) Steering Accumulators - Check and charge brake accumulators (17) and steering accumulators (18). Refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures".
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Table 15 Brake System Accumulator Pre-Charge Ambient Temperature Pre-Charge Pressure −23.3° C (−10° F) 5135 kPa (745 psi) −17.8° C (−0° F) 5252 kPa (762 psi) −12.2° C (10° F) 5368 kPa (779 psi) −6.7° C (20° F) 5485 kPa (796 psi) −1.1° C (30° F) 5601 kPa (812 psi) 4.4° C (40° F) 5718 kPa (829 psi) 10° C (50° F) 5834 kPa (846 psi) 15.6° C (60° F) 5951 kPa (863 psi) 21.1° C (70° F) 6067 kPa (880 psi) 26.7° C (80° F) 6184 kPa (897 psi) 32.2° C (90° F) 6300 kPa (914 psi) 37.8° C (100° F) 6417 kPa (931 psi) 43.3° C (110° F) 6533 kPa (948 psi) 48.9° C (120° F) 6650 kPa (964 psi) 54.4° C (130° F) 6766 kPa (981 psi) 60.0° C (140° F) 6883 kPa (998 psi) Show/hide tableTable 16 Steering System Pressure Accumulator Pre-Charge Ambient Temperature Pre-Charge Pressure −23.3° C (−10° F) 8764 kPa (1271 psi) −17.8° C (−0° F) 8961 kPa (1300 psi) −12.2° C (10° F) 9159 kPa (1328 psi) −6.7° C (20° F) 9356 kPa (1357 psi) −1.1° C (30° F) 9553 kPa (1386 psi) 4.4° C (40° F) 9750 kPa (1414 psi) 10° C (50° F) 9948 kPa (1443 psi) 15.6° C (60° F) 10145 kPa (1471 psi) 21.1° C (70° F) 10342 kPa (1500psi) 26.7° C (80° F) 10539 kPa (1529 psi) 32.2° C (90° F) 10737 kPa (1557 psi) 37.8° C (100° F) 10934 kPa (1586 psi) 43.3° C (110° F) 11131 kPa (1614 psi) 48.9° C (120° F) 11328 kPa (1643 psi) 54.4° C (130° F) 11526 kPa (1672 psi) 60.0° C (140° F) 11723 kPa (1700 psi) - Purge the air from the fuel system. Refer to Operation and Maintenance Manual, SEBU9099, "Fuel System - Prime"
- Inflate the tires to the correct pressure and record the tire specifications in Table 17.
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Table 17 Tire Size Manufacturer Left Front Right Front Left Rear Outside Left Rear Inside Right Rear Inside Right Rear Outside - Verify that the engine cooling fan is not tied to the shroud.
Illustration 42 | g06365743 |
(1) Brake Drag Front
(2) Powered Stairway Down (3) Brake Oil Hot (4) Brake Drag Rear (5) Traction Control System (6) Auto Lube Malfunction (7) Engine Stop (8) Brake Pressure (9) Low Steering Pressure (10) Fuel Level (11) Electrical System Fault 2 (12) Engine Check (13) Hydraulic Oil Temperature (14) Hydraulic Oil Level (15) Retarder (Hot) (16) Electrical System Fault 1 |
Purge the brakes
- Prepare hydraulic components
- Open the two hydraulic tank gate valves
- Verify that all brake line and bleeder screws are tight
- Verify that all hydraulic line connections are installed correctly and are tight
- Verify all pressure gauges are tight and sealed
- Verify that all solenoids, sensors, and switches are installed and connected to the correct wiring connector
- Leave the manual drain buttons in the open position for initial start
Show/hide tableIllustration 44 g06396096 Side view of service center - Use service center (A) (If Equipped) for filling the hydraulic tank to ensure that hydraulic oil is being filtered. If machine is not equipped with service center, filter oil with a 4-micron filter before filling the hydraulic tank.
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Illustration 45 g06396171 Top view of case drain lines - Fill the hydraulic tank to the upper site gage (Body Lowered) or the lower site gage (Body Raised) depending on body position. Crack open the steering case drain line (B) and fan pump case drain line (C) to ensure that any air is bled out and that the drive pump is full of hydraulic oil. Disconnect breather hose at location (BB) and cap with tool (T3).
Note: Monitor case drain lines and capped breather port once tank is pressurized in step 6. As oil begins to escape these locations, tighten case drain lines and breather cap.
Show/hide tableIllustration 46 g06396218 View of hydraulic cabinet - Replace brake accumulator pressure gage in hydraulic cabinet at location (D) with elbow connector and quick disconnect test fitting Tooling (T4) per Illustration 46. Connect one end of an air purge line to test fitting and place other end of line into suitable container.
Note: Hydraulic cabinet is equipped with factory installed gages. Gages may be replaced with pressure taps.
Show/hide tableIllustration 47 g06396276 View of hydraulic tank - Temporarily remove breather (E) located at the top of the hydraulic tank and cap hole. Insert an air adapter and regulator at location (F) per Illustration 47.
- Pressurize hydraulic tank to
70 kPa (10 psi) to prime hydraulic system.Do not put additional pressure on hydraulic system.70 kPa (10 psi) Maximum.Note: Do not start the engine
Show/hide tableIllustration 48 g06396764 Battery disconnect switch and emergency shut down - Depress emergency shutdown (H) and activate battery disconnect switch (G) to dry-start engine. Perform at least two dry-start cranks for 15 seconds maximum. Wait at least one minute between engine cranks.
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NOTICE At brake accumulator pressure tap (D), the first crank may only show a small amount of oil present after 15 seconds. The second crank should show a steady stream of oil. If a steady clear oil stream is not showing, repeat until a steady clear oil stream is present. This is a critical step for filling the hydraulic cabinet to purge air from the highest location in the hydraulic circuit.
- After air has been purged from hydraulic cabinet, remove air supply that was installed in Step 5. Reinstall hydraulic tank breather that was removed in Step 5 and drive box breather hose in location (BB) that was capped off in Step 3.
- Remove brake accumulator air purge line that was installed in Step 4.
- Verify hydraulic oil level in hydraulic tank and add oil as required.
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Illustration 49 g06397888 Steering Manifold located on inside Left-Hand frame rail. - Remove test fitting in location (J) and replace with elbow connector and quick disconnect test fitting Tooling (T4).
- Connect a
34474 kPa (5000 psi) pressure gage to the steering pump test fitting (J). - Start engine and run at low idle. If abnormal pump noise is detected, shut engine off. Repeat Steps 5 through 10. If no abnormal pump is detected continue to Step 14.
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Illustration 50 g06398173 Top view of steering pump compensator valve location - Run engine at low idle and allow the machine system pressures to settle. Verify steering pump output pressure of
24100 ± 700 kPa (3500 ± 100 psi) at location (J). Adjust the steering pump compensator valve (K) setting if required. - Slowly perform steering cycles through the entire steering range. Go from stop to stop. Do not hold at full stop and immediately switch direction. Perform at least 6 cycles (3 in each direction). Re-center the front tires when steering cycles are completed.
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Illustration 51 g06398352 Priority Valve located on inside Left-Hand frame rail. - Listen to blower motor. Verify that the motor is operating at a steady rpm of 1250 ± 50 (check in Advisor menu) with engine at low idle. If the blower motor speed is unsteady, measure priority valve pressure at location (M) and lower valve pressure setting at location (N).
- Install Test fitting Tool (T5) in location (M)
- Clockwise turn increases pressure, counterclockwise turn decreases pressure
- Priority valve pressure settings should not be set below
20684 kPa (3000 psi)
Show/hide tableIllustration 52 g06398433 Top view of fan pump solenoid location - Unplug fan pump connector (P) to bring pump to full displacement. Run the fan for at least 2 minutes. Reconnect fan pump connector (P). Verify fan rpm reduces to a slow/loping speed.
- Operate hoist system at low idle. Raise body to full raised position. Immediately lower body by power down mode. Repeat the raise and lower cycle 5 times.
- Shut down machine for 30 to 60 minutes to allow any air in the hydraulic system to vent out of the hydraulic tank breather (E). Verify hydraulic oil level and add oil if necessary.
- Restart the engine and run at low idle.
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Illustration 53 g06400470 Brake bleed locations - Purge the brake system. Refer to Testing and Adjusting, UENR2267, "Brake System Air - Purge" and bleed the following systems in order.
Note: Service brakes and parking brakes should be purged of air for a minimum of 1 minute at each wheel to ensure that a steady stream of clear oil is flowing.
Note: Use secondary brake pedal (Red Pedal) for service brake purging.
Note: Bleeders may need to be installed in parking brake bleeder locations. Install tooling (T6) onto park brake bleed locations as required.
- Service brake front slack adjuster (P1)
- Service brake left front wheel (P2)
- Service brake right front wheel (P3)
- Service brake rear slack adjuster (P4)
- Service brake left rear wheel (P5)
- Service brake right rear wheel (P6)
- Park brake relay valve in hydraulic cabinet (P7)
- Parking brake left front wheel (P8)
- Parking brake right front wheel (P9)
- Parking brake left rear wheel (P10)
- Parking brake right rear wheel (P11)
Show/hide tableIllustration 54 g06400170 SOS port location - Obtain hydraulic oil sample at the SOS sampling port (R) at oil cooler inlet.
Note: If there is no SOS port in location (R), install tool (T7)
- Check particle count.
- Refer to Tool Operating Manual, NEHS0799, "170-8500 Analyzer Group" for proper installation and operation. Caterpillar recommends connecting the on-line particle counters directly to the SOS valve.
- Refer to Operation and Maintenance Manual, SEBU6250, "Caterpillar Machine Fluids Recommendations" for fluid cleanliness recommendations.
- If kidney looping is required, refer to Contamination Control Guidelines, SEBF8840, "Basic Principles of Kidney Loop Filtering Hydraulic Fluid Systems"
- Change filter elements. Inspect filter elements for metallic particles that may be a sign of pump damage. Cut into filter pleats if deeper investigation is required.
- Change or inspect breathers as required.
- Recheck particle count.
Start the Engine
- Verify that all the fluids are at an acceptable level.
Note: Refer to the Operation and Maintenance Manual, SEBU9099, "Capacities (Refill)" for the fluid capacities.
- Perform air inlet system test. This test must be performed prior to starting the engine. Refer to Testing and Adjusting, UENR2267, Air Inlet System - Test and Inspect.
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Illustration 55 g06322198 View of the battery disconnect switch - Move battery disconnect switch (A) to the ON position.
- Chock the wheels.
- Ensure that the machine is in PARK.
- Hold the key switch to the START position to prime the engine. The engine will pre-lube until the engine builds
48 kPa (7 psi) or for 45 seconds.Note: Do not allow the engine to start. Do not cycle the key to override the engine pre-lube. If the engine does not crank, turn off the key for 30 seconds and repeat Step 6.
- Start the engine and allow the engine to run for 10 seconds. After 10 seconds, turn the key switch to the OFF position.
- Use Cat ET and hydraulic cabinet to monitor pressures and temperatures.
- Verify all the hydraulic and engine fluid levels and adjust as needed.
- Repeat Step 7 and Step 9 until all the fluid levels are correct.
Note: The Advisor may instruct the operator to shut down the engine to resolve any issues. All issues must be resolved before restarting the engine.
- Start the engine again and allow the engine to idle.
- Perform a walk around inspection to check for leaks. Monitor all the engine and hydraulic fluid levels.
- With the engine on, turn the steering wheel from the center position to the left. Next, turn the steering wheel back to the center position. Verify that the wheels turn in the correct direction.
Note: To reduce excessive wear of the tires. do not turn the wheels full right or full left.
- Turn the engine off.
Pressure Specifications
Hoist System | |
---|---|
Hoist Raise Pressure | |
Hoist Lower Pressure | |
Brake System | |
---|---|
Accumulator Nitrogen Charge Pressure | |
Service Brake Valve Pilot Pressure | |
Pressure at the brake packs (packs fully depressed) | |
Parking Brake | |
---|---|
Parking Brake Release Pressure | |
Parking Brake Pressure in PARK | |
Parking Brake Pressure in NEUTRAL | |
Steering System | |
---|---|
Accumulator Nitrogen Charge Pressure | |
Steering Pump High Idle RAX Off | |
Accumulator Pressure Test | |
Steering System Load Sensing Relief | |
Perform the Aftertreatment System Functional Test (if Tier 4 Equipped)
NOTICE |
---|
Confirm that the latest software vintage is flashed to the engine and aftertreatment prior to performing functional testing. |
Note: All images of Cat Electronic Tecnician (ET) screens are for reference only. Use the most upto date version of ET available.
- Use a laptop computer to open Cat Electronic Technician (ET).
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Illustration 56 g06369745 Show/hide tableIllustration 57 g06369675 Side view of machine
(1) Clean Emissions Module (CEM)
(2) Pump Electronic Tank Unit (PETU) - Confirm correct serial numbers for the Clean Emissions Module (CEM) and Pump Electronic Tank Unit (PETU).
- Check the value of the "Factory Installed Aftertreatment #1 Identification Number" and ensure that the serial number is correct. If incorrect, enter the correct number.
- Check the value of the "Aftertreatment DEF Pump Electronics Tank Unit Identification Number" and ensure that the serial number is correct. If incorrect, enter the correct number.
Show/hide tableIllustration 58 g03825970 - From the toolbar, select "Diagnostics" then "Diagnostic Tests".
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Illustration 59 g06369767 - Select "Aftertreatment System Functional Test" and click "Start".
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Illustration 60 g03825152 - Read and understand the warning. Click "OK" to proceed to the test.
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Illustration 61 g03825157 - Click "Next" to proceed to the test.
Charge the A/C system with refrigerant
Illustration 62 | g06345392 |
Air conditioning compressor location |
Refer to Testing and Adjusting, UENR4125, "Air Conditioning and Heating R134a for All Cat Machines". Check and charge the Air Conditioning system.
Ground Level Controls Function
Illustration 63 | g06321963 |
Battery disconnect switch |
Illustration 64 | g06321955 |
Lighting and engine shutdown switch |
Ground Level Controls | Check if OK |
---|---|
Turn the battery disconnect switch (1) to the ON position | |
Turn the ignition key to the ON position | |
Turn on the access light switch (2) | |
Turn on the engine compartment light switch (3) | |
Start the engine | |
Press the engine shutdown switch (4), engine should stop(1) | |
Pull out engine shutdown switch (4) | |
Start the engine | |
Turn the ignition key to the OFF position |
(1) | Shutdown switch (4) stops fuel flow to the engine. Steering system may still be able to operate with accumulator pressure. |
Cab Instrumentation and Functional Checks
Illustration 65 | g06321553 |
(1) Flood Light
(2) Engine Stop/Start Switch (3) Load Brake Button Switch (4) Power Outlet/Cigar Lighter (5) Press to Test (Lamp Check) (6) Park Brake Indicator (7) Air Conditioner Switch (8) Heater Switch (9) Fan Speed Switch (10) Accelerator Pedal (11) Hoist Control (12) Dynamic Retarder Pedal (13) Service Brake Control Pedal (14) Steering Wheel Control (15) Steering Wheel Tilt and Telescope Control (Lever) (16) Multifunction Switch (17) Delayed Engine Shutdown Switch (18) Auto Lube Manual Operation Switch (19) Auto Lube Alarm Reset (20) Throttle Lock (21) Stairway Light (22) Head/Tail Light (23) Window Wiper/Washer Switch (24) Front Fog Light Switch (If equipped) (38) Radio |
Cab Doors
Check the operation of Cab Doors | Check if OK | |
---|---|---|
LH | RH | |
Proper seal when door is closed | ||
Ensure outside handle function | ||
Ensure inside handle function | ||
Turn the ignition key to the ON position | ||
Fully lower and raise power window | ||
Turn the ignition key to the OFF position |
Pressurize the Cab
Check the Operation of the Blower Motor to Pressurize the Cab(1) | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Turn switch (9) to check the four blower speeds(2) | |
Turn the ignition key to the OFF position |
(1) | Pressurizing the Cab helps to eliminate dust in the operators compartment |
(2) | There should be an audible sound between the different settings |
Climate Control
Illustration 66 | g06288640 |
Heater lines location (H1) Supply heater valve (H2) Return heater valve |
Check the operation of the Heater and the Air Conditioner | Check if OK |
---|---|
Ensure heater lines (H1) and (H2) are open | |
Start the engine | |
Turn on the blower motor switch (9) | |
Turn on air conditioner switch (7) | |
Air from the dash vents should be cold(1) | |
Turn off air conditioner switch (7) | |
Turn on heather switch (8) | |
Air from the dash vents should be warm (1) | |
Turn the ignition key to the OFF position |
(1) | When the engine is at operating temperature |
Window Wipers
Check the Operation of the Window Wiper and Washer | Check if OK |
---|---|
Turn the ignition key to the ON position | |
From the OFF position, turn the window wipers to the LOW setting | |
Turn the window wiper switch (23) to the HIGH setting | |
Press the button to activate the window washer fluid | |
Turn the window wiper to the first INTERMITTENT setting | |
Turn the window wiper to the second INTERMITTENT setting | |
Turn the window wiper to the third INTERMITTENT setting | |
Turn the window wipers to the OFF position | |
Turn the ignition key to the OFF position |
Flood Light
Check the operation of the Panel Lights and the Headlights(1) | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Pushing switch (1) up to the first detent turns on the Park Lights and the Taillights. Pushing switch (1) to the second detent turns on the headlights (4) , park lights, and taillights | |
Dimmer for the panel lights. Pressing the top of the switch makes the lights brighter and the bottom makes the lights dimmer | |
Use multifunction switch (3) to toggle between low beam lights (4) and high beam lights (5) | |
Push the bottom half of switch (1) to the OFF position to deactivate the headlights | |
This switch turns on the fog lights and works only when the headlights are on low | |
Need to verify that the park lights and tail lights are operational |
(1) | The tail lights should be on any time a light switch is activated |
Front Fog Light
Check the operation of the Fog Lights | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Push the top half of switch (24) to activate fog lights (6) | |
Push the bottom half of switch (24) to deactivate fog lights (6) |
Head/Tail Light
Check the operation of the Head/Tail Lights | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Push the top half of switch (22) to activate Head/Tail Lights | |
Push the bottom half of switch (22) to Head/Tail Lights |
Stairway Light
Check the operation of the Auxiliary Lights(1) | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Push the top half of switch (9) or switch (10) to activate the access lights | |
If necessary, adjust the access light to provide light for the steps | |
Push the bottom half of switch (9) or switch (10) to deactivate the access lights |
(1) | The access lights can be activated from two places on the machine. The position of one switch will determine whether the other switch is in the ON position or in the OFF position. |
Turn Signal
Check the operation of the Turn Signals | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Use multi function switch (16) to activate Left turn signal | |
Use multi function switch (16) to activate Right turn signal |
Hazard Lights
Check the operation of the Hazard Lights | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Use multi function switch (16) to activate the Hazard Lights |
Brake Lights
Check the operation of the Brake Lights | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Depress dynamic retarder pedal (12) check brake lights | |
Depress service brake pedal (13) check brake lights |
Backup Alarm
Check the operation of the Backup Alarm(1) | Check if OK |
---|---|
The engine is running | |
Move the shift control lever and the speed control lever to the REVERSE position | |
The backup alarm should sound immediately(2) |
(1) | Make sure that the area behind the machine is clear of personnel and clear of obstacles |
(2) | The backup alarm should sound until the shift control lever and speed control lever are moved to the NEUTRAL position or the FORWARD position. |
Radio
Check the operation of the Radio | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Power on radio (38) | |
Check functions of radio (38) |
Operators Seat
Illustration 67 | g06289649 |
(25) Headrest
(26) Armrest Angle (27) Heat/Vent Selector (If Equipped with Heated and Ventilated Seat (28) Backrest Angle (29) Ride Indicator (30) Fore/Aft Adjustment (31) Height Adjustment (32) Seat Heater/Ventilation (If Equipped with Heated or Heated and Ventilated Seat) (33) Damper (34) Seat Cushion Tilt (35) Lumbar Support (36) Seat Belt Latch (37) Shoulder Belt Adjustment |
Check for Seat Adjustability | Check if OK |
---|---|
Full range of the back reclining positions | |
Full range of the headrest positions | |
Full range of the arm rests positions | |
Full range of the seat cushion tilt | |
Full range of the seat suspension travel | |
Check the range of the light to heavy dampening for the seat | |
Full range of the lumbar support | |
Seat Heater/Ventilation function and adjustment (If Equipped) |
Check Seat Belt Latch and Seat Belt Adjustability | Check if OK |
---|---|
Adjust the length of the seat belt | |
Fasten the seat belt catch into the buckle | |
The seat belt must not be able to slip after adjusting | |
The seat belt catch should unlatch from the buckle when required |
Passenger/Buddy Seat
Illustration 68 | g06321914 |
(25) Headrest
(28) Backrest Angle (29) Ride Indicator (30) Fore/Aft Adjustment (31) Height Adjustment (33) Damper (34) Seat Cushion Tilt (35) Lumbar Support (36) Seat Belt Latch |
Check for Seat Adjustability | Check if OK |
---|---|
Full range of the back reclining positions | |
Full range of the headrest positions | |
Full range of the seat cushion tilt | |
Full range of the seat suspension travel | |
Check the range of the light to heavy dampening for the seat | |
Full range of the lumbar support |
Check Seat Belt Latch and Seat Belt Adjustability | Check if OK |
---|---|
Adjust the length of the seat belt | |
Fasten the seat belt catch into the buckle | |
The seat belt must not be able to slip after adjusting | |
The seat belt catch should unlatch from the buckle when required |
Speedometer Calibration
Illustration 69 | g06341964 |
Depress buttons (A) and (B) while turning on the ignition to enter the setup menu.
Calibrate the speedometer per settings in Operation and Maintenance Manual, SEBU9099, " Monitoring System ".
Speedometer Menu | Setting Selection |
---|---|
Self Test | |
Engine Type | |
Speedo Source |
Purge the Autolube System
- Manually purge the autolube system.
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Illustration 70 g03784049 View for the front left-hand and right-hand side injectors Show/hide tableIllustration 71 g06322255 View for the rear injectors - Adjust the grease injectors, as required. Refer to Testing and Adjusting, UENR2267, "Automatic Lubrication System - Adjust".
NOTICE |
---|
Ensure that all the automated grease injectors are receiving a sufficient supply of grease. |
Inspect Grease Points
Inspect the grease points of the automatic lubrication system. Ensure that grease is reaching all points of lubrication.
Manually Actuate Grease System
Illustration 72 | g06323336 |
Autolube pressure gauge (1) Manual Actuation Button |
Use button (1) to manually actuate the autolube system. Ensure that the pressure builds in the system to
Verify Grease Alarm Function
- Change setting of timer (2) from minutes to seconds.
- Manually actuate autolube system. Autolube warning light should activate.
Note: The changed timer setting does not allow enough time for pressure to build in the system before attempting to cycle again. The low pressure warning is normally an indication of no grease in the tank or a broken line to the injector banks.
- Reset timer (2) to minutes.
Illustration 73 | g06341148 |
Autolube cycle timer location (2) Autolube Timer |
Body Installation Inspection
Record Body information | |
---|---|
Body Manufacturer/Part Number | |
Serial Number | |
Condition |
Body to Chassis Interference
- When properly shimmed there should be no gaps between the body and the chassis.
- If the truck is equipped with body heat, verify the proper adjustment of the body heat connection.
- Check the hoses on top of the hydraulic tank, fuel tank, and the hoses between the frame rails. If necessary, adjust the grease line at the top of the hoist cylinder to prevent any damage.
Suspension Cylinder Charging
Dump body must be installed for proper suspension cylinder charging.
Rear Suspension Charge
- Ensure that the machine is on a level surface, the wheels are chocked, and the frame and dump body are clean from dirt and debris.
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Illustration 74 g06288171 Typical view of a rear suspension cylinder
(A) Rear Suspension Assembly
(B) Measurement from Center of Pin to PinNote: Rear suspension cylinders should be charged simultaneously
- For both rear suspension cylinders (A), verify proper oil height by measuring from pin center to pin center. A pin to pin measurement (B) of
1514.6 mm (59.63 inch) indicates proper oil height prior to nitrogen charge.Refer to Special Instruction, M0092742, "Servicing the Suspension Cylinders for 794 AC Off-Highway Trucks" for adding oil to suspension cylinders.
- Charge rear suspension cylinders (A) until pin to pin measurement (B) reaches
1571.75 ± 13 mm (61.88 ± 0.5 inch) .Refer to Special Instruction, M0092742, "Servicing the Suspension Cylinders for 794 AC Off-Highway Trucks" for suspension cylinder charging procedure.
Rear Suspension Cylinders | ||||
---|---|---|---|---|
Pin to Pin Oil Level | Pin to Pin Final | |||
Target | Actual | Target | Actual | |
Left Cylinder | |
|
||
Right Cylinder |
Front Suspension Charge
- Ensure that the machine is on a level surface, the wheels are chocked, and the frame and dump body are clean from dirt and debris.
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Illustration 75 g06288226 Typical view of a front suspension cylinder
(C) Front Suspension Assembly
(D) Measurement from Center of Pin to PinNote: The front suspension can be charged individually or simultaneously.
- For both front suspension cylinders (C), verify proper oil height by measuring from pin center to pin center. A pin to pin measurement (D) of
1593.85 mm (62.75 inch) indicates proper oil height prior to nitrogen charge.Refer to Special Instruction, M0092742, "Servicing the Suspension Cylinders for 794 AC Off-Highway Trucks" for adding oil to suspension cylinders.
- Charge front suspension cylinders (C) until pin to pin measurement (D) reaches
1755 ± 13 mm (69.1 ± 0.5 inch) .Refer to Special Instruction, M0092742, "Servicing the Suspension Cylinders for 794 AC Off-Highway Trucks" for suspension cylinder charging procedure.
Front Suspension Cylinders | ||||
---|---|---|---|---|
Pin to Pin Oil Level | Pin to Pin Final | |||
Target | Actual | Target | Actual | |
Left Cylinder | |
|
||
Right Cylinder |
Check the Configuration of the Electronic Control Modules (ECM)
Reference: Service Manual, UENR3957, "794 AC Off-Highway TruckVIMS 3G and Truck Payload Measurement System (TPMS)"
Reference: Refer to Service Magazine, SEPD1178, "Switch Settings for the Payload Monitors" for additional information on the switch settings for the payload monitors.
Check for Active Diagnostic Codes and Logged Diagnostic Codes
Note: The payload diagnostic codes will be active until the system is calibrated.
- From the toolbar, click "Diagnostic". Click "Active Diagnostic Codes".
- Resolve any of the active diagnostic codes.
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Illustration 77 g03868247 - From the toolbar, click "Diagnostics". Click "Logged Diagnostic Codes".
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Illustration 78 g03868249 Typical view - Clear any logged diagnostic codes by highlighting an event. Next, click the "Clear" button that is located in the lower left corner of the screen.
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Illustration 79 g03868330 - From the toolbar, click "Diagnostics". Select "Events" and click "Logged Events".
- If necessary, resolve any logged events and clear any logged events.
- Clear the logged event by selecting an event and clicking the "Clear" button that is located in the lower left corner of the screen.
Note: A factory assigned password may be required to clear some events that are logged on the engine "ECM".
Illustration 76 | g03868244 |
Ground Protection
The Power Train Electric Drive System will contain hazardous voltage levels during machine operation and for a short period of time after engine shutdown. Do not remove any covers that will expose energized high voltage electrical components while the engine is operating. Any type of maintenance on the following components can only be performed after the Power Train Electrical System Service Shutdown procedure has been followed:
Failure to follow these instructions could result in personal injury or death. |
- Prepare the machine for maintenance. Shut down and discharge the high-voltage electrical system.
Note: Refer to Operation and Maintenance Manual, SEBU9099, "794 AC Off-Highway Truck" for additional information on the ground protection.
Show/hide tableIllustration 80 g06289594 - Open cover (1) for the retarding contactor compartment on the inverter cabinet.
- Temporarily attach an insulated jumper wire FROM ground plate (2) TO EITHER DC positive bus bar (3) OR DC negative bus bar (4).
- Close the cover for the retarding contactor compartment.
- Deactivate the engine lockout control. refer to Operation and Maintenance Manual, "Engine Lockout Control" for more information.
- Start the engine and allow the voltage for the DC power bus to climb above 500V.
Note: The voltage for the DC power bus can be monitored on the Advisor screen or through ET.
- Verify that a warning category 1 ground fault event is logged. The message "DC Ground Fault" can be viewed through the Advisor screen or through ET.
Note: The message "DC Ground Fault" will take approximately 10 seconds to be logged.
- If a warning category 1 ground fault event is not logged, troubleshoot the ground fault procedure. For more information, refer to Troubleshooting, UENR3890 or contact your Caterpillar dealer.
- Stop the engine.
- Perform the drive train electrical system shutdown procedure.
- Open the cover for the retarding contactor compartment.
- Remove the temporary jumper wire and securely close the access door.
- Close the cover for the retarding contactor compartment.
Perform Brake Holding Tests
Refer to Operation and Maintenance Manual, SEBU9099, "Braking System - Test" and perform the braking tests.
Brake Holding Tests | Check if OK |
---|---|
Service Brake Holding Ability Test | |
Secondary Brake Holding Ability Test | |
Parking Brake Holding Ability Test | |
Load Brake Test |
Steering System Test
Reference: Testing and Adjusting, UENR2267, Steering System - Check
- Chock the wheels. Start the engine and run at high idle.
- Turn the steering wheel to the left and hold it against the stop. Check for leaks and verify accumulator pressure.
- Turn the steering wheel to the right and hold it against the stop. Check for leaks and verify accumulator pressure.
- Turn the steering wheel from one stop to the other stop and count the revolutions.
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Table 45 Steering System Test Test Actual Check if ok Steering Wheel Left No Leaks Accumulator Pressure 24131 ± 690 kPa (3500 ± 100 psi) Steering Wheel Right No Leaks Accumulator Pressure 24131 ± 690 kPa (3500 ± 100 psi) Stop to Stop 6 Revolutions Max
Note: A full right or left turn shall be made with a reasonable amount of effort.
Set Engine Radiator Maximum Speed
- Chock the wheels.
- Start the engine.
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Illustration 81 g06287751 Bottom view
(1) Radiator Fan Pump - Unplug solenoid from pump (1) to increase pump flow to maximum output.
- Use Cat ET or VIMS Monitor to verify fan speed per specifications in table 46.
Note: Pump (1) adjustments may be required.
Hydraulic Fan Speed | |
---|---|
Actual Fan Speed At Low Idle | 255 rpm at 700 Engine rpm |
Actual Fan Speed At High Idle | 650 rpm at 1800 Engine rpm |
Set Drivetrain Cooling Fan Speed
- Chock the wheels.
- Start the engine.
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Illustration 82 g06287836 (1) Drivetrain Cooling Fan Pump - Unplug solenoid from pump (1) to increase pump flow to maximum output.
- Use Cat ET or VIMS Monitor to verify fan speed per specifications in table 47.
Note: Pump (1) adjustments may be required.
Show/hide tableIllustration 83 g06365558 (2) Rear Axle Housing Vent - Verify sufficient air flow out of the rear axle housing vent (2) with drivetrain cooling fan running.
Blower Fan Speed | ||
---|---|---|
Engine Speed | Target Fan Speed | Actual |
Below 1300 rpm | 1250 ± 25 rpm | |
Above 1300 rpm | 2800 to 3200 rpm |
Grid Dry Function
Illustration 84 | g03664695 |
Use adviser to manually activate Grid Dry function.
Refer to Operation and Maintenance Manual, SEBU9099, " Monitoring System " for more information on Grid Dry function and settings.
Grid Dry | Check if OK |
---|---|
Manual Grid Dry function |
Engine Performance Test
NOTICE |
---|
Clear personnel from machine platform before performing test. |
- Refer to Engine Performance - Test, UENR2267 and perform test.
Note: The engine should be at normal operating temperature and the shift control lever should be in the PARK position.
- Record figures from test for a baseline.
Note: A screen shot can be taken in ET for records.
Manual Motor Disable
- Prepare the truck to be moved.
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Illustration 85 g02207433 - Select the "Service Settings" and press "OK".
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Illustration 86 g02207473 - Enable the "Service Mode". Press the "HOME" button after enabling the service mode.
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Illustration 87 g02207494 - Select "Settings" from the main menu. Press "OK".
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Illustration 88 g02207515 - Select "Drivetrain". Press "OK".
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Illustration 89 g02207535 - Select "Drv Mtr Disable Config". Press "OK".
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Illustration 90 g02207554 - Use the arrows to select the drive motor that you would like to disable. Press "OK" after you have selected the correct motor.
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Illustration 91 g02207693 - The following message will be displayed to show which motor has been disabled.
- Disable drive motor one.
- Place the shift control lever into D and move the truck forward.
Note: Verify that the truck moves in the correct direction and that no faults were logged.
- Place the shift control lever into R and move the truck backward.
Note: Verify that the truck moves in the correct direction and that no faults were logged.
- Engage drive motor one.
- Disable drive motor two.
- Place the shift control lever into D and move the truck forward.
Note: Verify that the truck moves in the correct direction and that no faults were logged.
- Place the shift control lever into R and move the truck backward.
Note: Verify that the truck moves in the correct direction and that no faults were logged.
- Engage drive motor two.
Note: Verify that both drive motors are enabled.
NOTICE |
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Clear the surrounding area around the truck. The motor disable procedure requires moving the machine. |
Truck Payload - Calibrate
Dump body installation and suspension cylinder charging must be completed prior to payload calibration.
- Select the "Service" mode. Select "Calibration" mode.
Show/hide table
Illustration 93 g02202276 - Select "Truck Payload" mode.
Show/hide table
Illustration 94 g02202278 - Select "Truck Payload Calibration".
Illustration 92 | g02202273 |
Emissions Compliance Report (Tier 4 Equipped Machines)
- From the toolbar, click "Information" and "Product Status Report".
Show/hide table
Illustration 96 g03394193 - Run the Product Status Report.
Note: The Product Status Report will show the injector codes.
Illustration 95 | g06370761 |
After you complete the final check, sign your name and the name of the dealer. Make copies of the check procedure, and the Product Status Report as an ".xml" file. Mail (or e-mail) the copies to the following addresses:
Note: If needing to view the ".xml" file, word-processing software can be used.
Caterpillar Inc.Attention: Product Support Engineer
794 AC Off-Highway Trucks
97 E. Congress St
Tucson, AZ 85701
Caterpillar Inc.
P.O. Box 600
Mossville, Illinois 61552-0600
Attention: Emissions Compliance Manager
Also, email a copy of the check procedure to:
Emissions_Compliance@cat.comDealer:____________________
Inspector Signature:____________________
Customer:____________________
Product Identification Number:____________________
Baseline Measurements
Operate the machine for 50 hours. After the initial 50 hours of operation baseline measurements of the following procedures must be recorded. Comparing the baseline measurements to future measurements of the same procedures, helps track component wear.
Record baseline measurements of the following procedures:
Kingpin Baseline Check
Refer to Testing and Adjusting, UENR2267, Kingpin (Front) - Check for the procedure to establish Kingpin Baselines.
Kingpin Measurement | ||
---|---|---|
Machine Side | Indicator Location | Baseline Measurement |
Right-hand Kingpin | Upper | |
Lower | ||
Left-hand Kingpin | Upper | |
Lower |
Rear Axle Housing Bearing (Nosecone) Baseline Check
Refer to Testing and Adjusting, UENR2267, Rear Axle Housing Bearing - Inspect for the procedure to establish Rear Axle Housing Bearing (Nosecone) Baselines.
Rear Axle Housing Bearing (Nosecone) Baseline | |||
---|---|---|---|
Trial Number | Vertical | Horizontal 1 | Horizontal 2 |
Trial 1 | |||
Trial 2 | |||
Trial 3 |
Brakewear Indicator Baseline Check
Refer to Testing and Adjusting, UENR2267, Service Brake Discs - Check for the initial set up procedure of Front Brake Wear Indicators and the procedure to establish Rear Brake Wear Baselines.
Initial Setting of the Front Brake Wear Indicator | |
---|---|
Wheel | Setting Complete |
RH Front Wheel | |
LH Front Wheel |
Rear Brake Wear Baseline | |
---|---|
Wheel | Baseline Measurement |
RH Rear Wheel | |
LH Rear Wheel |
Worksheets
Dealer Information for Commissioning Procedure | |
---|---|
Date | |
Serial Number | |
Service Meter Units | |
Name of the Technician | |
Unit Number | |
Engine Serial Number | |
Pump Electronic Tank Unit (PETU) Serial Number(1) | |
Clean Emissions Module (CEM) Serial Number(1) | |
Dealer | |
Dealer Code | |
Customer | |
Job Site | |
Right-Hand Wheel Station Serial Number | |
Left-Hand Wheel Station Serial Number | |
Rear Axle Serial Number | |
Body Manufacturer/Part Number | |
Body Serial Number | |
General Body Condition |
(1) | If Tier 4 equipped |
Miscellaneous Checks | |
Take Digital Photos of Completed Truck | |
Missing Parts(1) | |
Performance Issues | |
Dealer Installed Attachments(2) | |
Dealer Comments(3) | |
Verify the function of all Cab Controls | |
Verify the function of the Engine Aftertreatment(4) | |
Payload Target |
(1) | Develop a list of all the part numbers and the next highest part number level. |
(2) | Take digital photos of all dealer installed attachments. |
(3) | Record positive and negative comments. |
(4) | If Tier 4 equipped |
Checking the Fluid Levels | Check if OK |
---|---|
Engine Coolant System(1) | |
Hydraulic Tank | |
Engine Crankcase | |
Left Rear Final Drive | |
Right Rear Final Drive | |
Grease for the Autolube | |
Left Front Wheel Station | |
Right Front Wheel Station | |
Window Washer Reservoir | |
Fuel | |
Diesel Exhaust Fluid (DEF)(2) |
(1) | Check the Jacket Water level. |
(2) | If Tier 4 Equipped |
Location of Ground Straps | Check if OK | ||
---|---|---|---|
Ground Strap | Location | ||
G1 | Generator | Right side of the generator to Right- Hand frame rail.(1) | |
G2 | Engine | Right rear engine mount to Right-Hand frame rail.(1) | |
G3 | Upper Cooler | Left-Hand side of cooler to inside of Left-Hand frame rail.(1) | |
G4 | Radiator Group | Left-Hand bottom of cooler to Left-Hand cooler mount.(1) | |
G5 | Superstructure | Left-Hand rear superstructure saddle mount to Left-Hand frame rail.(1) | |
G6 | Rear Axle Housing | Top of rear axle housing front center linkage to frame near cross tube.(1) | |
G7 | RH Drive Motor | Inside the rear axle housing.(2) | |
G8 | LH Drive Motor | Inside the rear axle housing.(2) | |
G9 | Cab | Right front corner under the cover.(2) | |
G10 | Upper Upright Beam | Top box to Left-Hand upright beam.(2) | |
G11 | Lower Upright Beam | Lower box to Left-Hand upright beam(2) | |
G12 | ECM Cabinet | Bottom of ECM cabinet to the deck.(2) | |
G13 | Retarding Grid | Inboard side of the retarding grid to the deck.(2) | |
G14 | Inverter Cabinet | Two cables at the Right rear of the inverter cabinet by cable entry.(2) |
(1) | Refer to Illustration 7 |
(2) | Refer to Illustration 8 |
Pins, Retainers, and Hardware | ||
---|---|---|
Inspection Area | Left-Hand Side | Right-Hand Side |
Platform Connections | ||
Front Suspension Cylinders | ||
Front Axle Connections | ||
Steering Linkages | ||
Hoist Cylinders | ||
Rear Axle Housing Nosecone Bushing | ||
Rear Axle Housing Rear Linkage | ||
Rear Suspension Cylinders | ||
Rear Dump Body Pins |
Tire Size | Manufacturer | |
---|---|---|
Left Front | ||
Right Front | ||
Left Rear Outside | ||
Left Rear Inside | ||
Right Rear Inside | ||
Right Rear Outside |
Ground Level Controls | Check if OK |
---|---|
Turn the battery disconnect switch (1) to the ON position | |
Turn the ignition key to the ON position | |
Turn on the access light switch (2) | |
Turn on the engine compartment light switch (3) | |
Start the engine | |
Press the engine shutdown switch (4), engine should stop(1) | |
Pull out engine shutdown switch (4) | |
Start the engine | |
Turn the ignition key to the OFF position |
(1) | Shutdown switch (4) stops fuel flow to the engine. Steering system may still be able to operate with accumulator pressure. |
Check the operation of Cab Doors | Check if OK | |
---|---|---|
LH | RH | |
Proper seal when door is closed | ||
Ensure outside handle function | ||
Ensure inside handle function | ||
Turn the ignition key to the ON position | ||
Fully lower and raise power window | ||
Turn the ignition key to the OFF position |
Check the Operation of the Blower Motor to Pressurize the Cab(1) | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Turn switch (9) to check the four blower speeds(2) | |
Turn the ignition key to the OFF position |
(1) | Pressurizing the Cab helps to eliminate dust in the operators compartment |
(2) | There should be an audible sound between the different settings |
Check the operation of the Heater and the Air Conditioner | Check if OK |
---|---|
Ensure heater lines (H1) and (H2) are open | |
Start the engine | |
Turn on the blower motor switch (9) | |
Turn on air conditioner switch (7) | |
Air from the dash vents should be cold(1) | |
Turn off air conditioner switch (7) | |
Turn on heather switch (8) | |
Air from the dash vents should be warm (1) | |
Turn the ignition key to the OFF position |
(1) | When the engine is at operating temperature |
Check the Operation of the Window Wiper and Washer | Check if OK |
---|---|
Turn the ignition key to the ON position | |
From the OFF position, turn the window wipers to the LOW setting | |
Turn the window wiper switch (23) to the HIGH setting | |
Press the button to activate the window washer fluid | |
Turn the window wiper to the first INTERMITTENT setting | |
Turn the window wiper to the second INTERMITTENT setting | |
Turn the window wiper to the third INTERMITTENT setting | |
Turn the window wipers to the OFF position | |
Turn the ignition key to the OFF position |
Check the operation of the Panel Lights and the Headlights(1) | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Pushing switch (1) up to the first detent turns on the Park Lights and the Taillights. Pushing switch (1) to the second detent turns on the headlights (4) , park lights, and taillights | |
Dimmer for the panel lights. Pressing the top of the switch makes the lights brighter and the bottom makes the lights dimmer | |
Use multifunction switch (3) to toggle between low beam lights (4) and high beam lights (5) | |
Push the bottom half of switch (1) to the OFF position to deactivate the headlights | |
This switch turns on the fog lights and works only when the headlights are on low | |
Need to verify that the park lights and tail lights are operational |
(1) | The tail lights should be on any time a light switch is activated |
Check the operation of the Fog Lights | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Push the top half of switch (24) to activate fog lights (6) | |
Push the bottom half of switch (24) to deactivate fog lights (6) |
Check the operation of the Head/Tail Lights | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Push the top half of switch (22) to activate Head/Tail Lights | |
Push the bottom half of switch (22) to Head/Tail Lights |
Check the operation of the Auxiliary Lights(1) | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Push the top half of switch (9) or switch (10) to activate the access lights | |
If necessary, adjust the access light to provide light for the steps | |
Push the bottom half of switch (9) or switch (10) to deactivate the access lights |
(1) | The access lights can be activated from two places on the machine. The position of one switch will determine whether the other switch is in the ON position or in the OFF position. |
Check the operation of the Turn Signals | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Use multi function switch (16) to activate Left turn signal | |
Use multi function switch (16) to activate Right turn signal |
Check the operation of the Hazard Lights | Check if OK |
---|---|
Turn the ignition key to the OFF position | |
Use multi function switch (16) to activate the Hazard Lights |
Check the operation of the Brake Lights | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Depress dynamic retarder pedal (12) check brake lights | |
Depress service brake pedal (13) check brake lights |
Check the operation of the Backup Alarm(1) | Check if OK |
---|---|
The engine is running | |
Move the shift control lever and the speed control lever to the REVERSE position | |
The backup alarm should sound immediately(2) |
(1) | Make sure that the area behind the machine is clear of personnel and clear of obstacles |
(2) | The backup alarm should sound until the shift control lever and speed control lever are moved to the NEUTRAL position or the FORWARD position. |
Check the operation of the Radio | Check if OK |
---|---|
Turn the ignition key to the ON position | |
Power on radio (38) | |
Check functions of radio (38) |
Check for Seat Adjustability | Check if OK |
---|---|
Full range of the back reclining positions | |
Full range of the headrest positions | |
Full range of the arm rests positions | |
Full range of the seat cushion tilt | |
Full range of the seat suspension travel | |
Check the range of the light to heavy dampening for the seat | |
Full range of the lumbar support | |
Seat Heater/Ventilation function and adjustment (If Equipped) |
Check Seat Belt Latch and Seat Belt Adjustability | Check if OK |
---|---|
Adjust the length of the seat belt | |
Fasten the seat belt catch into the buckle | |
The seat belt must not be able to slip after adjusting | |
The seat belt catch should unlatch from the buckle when required |
Check for Seat Adjustability | Check if OK |
---|---|
Full range of the back reclining positions | |
Full range of the headrest positions | |
Full range of the seat cushion tilt | |
Full range of the seat suspension travel | |
Check the range of the light to heavy dampening for the seat | |
Full range of the lumbar support |
Check Seat Belt Latch and Seat Belt Adjustability | Check if OK |
---|---|
Adjust the length of the seat belt | |
Fasten the seat belt catch into the buckle | |
The seat belt must not be able to slip after adjusting | |
The seat belt catch should unlatch from the buckle when required |
Speedometer Menu | Setting Selection |
---|---|
Self Test | |
Engine Type | |
Speedo Source |
Record Body information | |
---|---|
Body Manufacturer/Part Number | |
Serial Number | |
Condition |
Rear Suspension Cylinders | ||||
---|---|---|---|---|
Pin to Pin Oil Level | Pin to Pin Final | |||
Target | Actual | Target | Actual | |
Left Cylinder | |
|
||
Right Cylinder |
Front Suspension Cylinders | ||||
---|---|---|---|---|
Pin to Pin Oil Level | Pin to Pin Final | |||
Target | Actual | Target | Actual | |
Left Cylinder | |
|
||
Right Cylinder |
Brake Holding Tests | Check if OK |
---|---|
Service Brake Holding Ability Test | |
Secondary Brake Holding Ability Test | |
Parking Brake Holding Ability Test | |
Load Brake Test |
Steering System Test | |||
---|---|---|---|
Test | Actual | Check if ok | |
Steering Wheel Left | No Leaks | ||
Accumulator Pressure | |
||
Steering Wheel Right | No Leaks | ||
Accumulator Pressure | |
||
Stop to Stop | 6 Revolutions Max |
Hydraulic Fan Speed | |
---|---|
Actual Fan Speed At Low Idle | 255 rpm at 700 Engine rpm |
Actual Fan Speed At High Idle | 650 rpm at 1800 Engine rpm |
Blower Fan Speed | ||
---|---|---|
Engine Speed | Target Fan Speed | Actual |
Below 1300 rpm | 1250 ± 25 rpm | |
Above 1300 rpm | 2800 to 3200 rpm |
Grid Dry | Check if OK |
---|---|
Manual Grid Dry function |
Kingpin Measurement | ||
---|---|---|
Machine Side | Indicator Location | Baseline Measurement |
Right-hand Kingpin | Upper | |
Lower | ||
Left-hand Kingpin | Upper | |
Lower |
Rear Axle Housing Bearing (Nosecone) Baseline | |||
---|---|---|---|
Trial Number | Vertical | Horizontal 1 | Horizontal 2 |
Trial 1 | |||
Trial 2 | |||
Trial 3 |
Initial Setting of the Front Brake Wear Indicator | |
---|---|
Wheel | Setting Complete |
RH Front Wheel | |
LH Front Wheel |
Rear Brake Wear Baseline | |
---|---|
Wheel | Baseline Measurement |
RH Rear Wheel | |
LH Rear Wheel |