Testing and Adjusting

Usage:

Troubleshooting

Machine Preparation for Troubleshooting

SMCS Code: 5050-035

Show/hide table

Personal injury or death can result from escaping fluid under pressure.
Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

Always use a board or cardboard when checking for a leak.

Show/hide table

Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

1. Move the machine to a smooth, horizontal location that is away from operating machines and away from personnel. Lower the bucket and/or attachments to the ground.

NOTE: Permit only one operator on the machine. Keep all other personnel away from the machine or in the operator's sight.

2. Put the transmission control in the NEUTRAL position and any speed position. Engage the primary steering/transmission lock lever (STIC steer machines) or the transmission neutral lock (wheel steer machiness).

3. Engage the parking brake. Place wheel blocks in front of the wheels and behind the wheels.

4. When the bucket and/or attachment is raised for testing or for adjusting, make sure that the bucket and/or attachment is supported correctly. Also, make sure that the bucket and/or attachment is fully in the DUMP position. The lift circuit has high oil pressure when the lift arms raise the front of the machine.

NOTE: Do not stop the machine with the front of the machine off the ground unless this is required for a test. Lower the machine to the ground and stop the engine.

5. Install the steering frame lock pin so that the machine can not articulate.

6. Stop the engine.

7. Move the hydraulic control lever several times through the full range of travel. This will relesae any pressure that may be present in the implement hydraulic system.

8. Move the STIC steering control several times in both directions to release the pressure in the steering system.

9. Depress the brake pedal at least eighty times to release any pressure in the brake accumulators.

10. Depress the breaker relief valve on the hydraulic tank in order to release the hydraulic oil pressure.

When you are analyzing a hydraulic system for poor performance, remember that correct oil flow and correct oil pressure are necessary for correct operation. Oil flow is a function of the pump output. The pump output is a function of engine speed. A restriction to the flow of oil causes oil pressure.

Visual Inspection

SMCS Code: 5050-035

Show/hide table

Personal injury can result from hydraulic oil pressure and hot oil.
Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.

Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

Show/hide table

Always use a board or cardboard when checking for a leak.

Show/hide table

Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine.
To prevent personal injury or death, perform the following:
Park the machine on a smooth, level surface.
Lower the bucket and/or attachments to the ground and engage the parking brake.
Stop the engine and remove the key.

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

The 5S-5123 Hydraulic Test Group, 8T-5320 Hydraulic Test Group or the 1U-5481 Pressure Gauge Group can be used to test the hydraulic system pressure. Before any tests are performed, visually inspect the entire hydraulic system for oil leaks and for damaged parts. For some of the tests, a magnet and a measuring rule (millimeters or inches) are usable tools.

When any test is performed on the hydraulic system, the hydraulic oil must be at the normal operating temperature. To increase the oil temperature, start the engine and turn the machine in both directions. Also, raise the bucket and/or attachment and lower the bucket and/or attachment.

When you diagnose a problem in the hydraulic system, a visual inspection of the hydraulic system is the first step. Stop the engine and lower the bucket and/or attachment to the ground. Perform the following inspections:

1. Check the oil level in the hydraulic tank. Locate the breaker relief valve on the hydraulic oil tank. Press and hold down the plunger on the breaker relief valve. Permit the pressure in the hydraulic tank to be released before the cap is removed.

2. Look for air in the hydraulic tank oil immediately after the engine is stopped. Use a clear container to obtain a sample of the oil. Look for air bubbles in the oil in the container.

3. Remove the filter elements and look for particles in the filter elements. A magnet will separate ferrous particles such as iron and steel from the nonferrous particles such as aluminium and rubber.

4. Check all oil lines and all connections for damage and for leaks.

Hydraulic System Troubleshooting

SMCS Code: 5050-035

Show/hide table

Personal injury can result from hydraulic oil pressure and hot oil.
Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressur eis not released before any service is done on the hydraulic system.

Show/hide table

Always use a board or cardboard when checking for a leak.

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

The lift and tilt circuits are connected in a series arrangement. The hydraulic pump and the main relief valve are common to the lift and tilt circuits. The circuits have makeup valves and check valves in the head ends and in the rod ends in order to prevent cylinder drift during movement of the valve spool.

The relief valves in the lift circuit and in the tilt circuit protect the components from pressures in the circuits when the control valves are in the HOLD position.

* The oil pressure for opening the relief valves must be within the specifications. Pressures that are too low will cause a decrease in the lifting force and in the dig characteristics. Pressures that are too high will cause a decrease in the life of hoses and of other components.

* Circuit drift is caused by leakage past cylinder pistons, past O-ring seals in the control valves, past check valves that do not seat correctly or past makeup valves that do not seat correctly. Poor adjustments of the control valves or incorrect fit may also contribute to circuit drift.

* Cycle times that are longer than normal result from oil leakage, from pump wear or from the pump speed.

If the basic tests indicate a leak in the circuit, install a flow meter and perform a test. This procedure will help to find the source of a leak.

Troubleshooting Problem List

1. The pump makes noise and the cylinder rods do not move evenly. There are also air bubbles in the oil.

2. The oil temperature is too high.

3. The pump output is low.

4. The oil pressure is low.

5. The attachment moves while the control lever is in the HOLD position.

6. The attachment droops when the control lever is moved from the HOLD position to the LIFT position.

Problem 1: The pump makes noise and the cylinder rods do not move evenly. There are also air bubbles in the oil.

Probable causes:

1. The viscosity of the oil is incorrect.

2. The main relief valve opens at low oil pressure.

3. There is a loose connection of the oil line on the inlet side of the pump.

4. The pump has too much wear.

Problem 2: The oil temperature is too high.

Probable causes:

1. The viscosity of the oil is incorrect.

2. The setting of the main relief valve is too low. This causes the main relief valve to open prematurely.

3. The implement pump has too much wear.

4. There is a restriction in an oil passage.

5. There is a high pressure oil leak in one or more circuits.

6. The load on the system is too high. This causes the main relief valve to open.

7. The oil level is low.

8. The oil is contaminated.

9. There is air in the hydraulic oil.

NOTE: A problem with air in the oil must be corrected before the hydraulic system will operate at normal temperatures.

There are two conditions that cause air to be in the hydraulic oil:

a. Return oil to the tank goes in above the level of the oil in the tank.

b. Air leaks in the suction line between the pump and the tank.

10. The hydraulic oil cooler is plugged.

Problem 3: The pump output is low.

Probable causes:

1. The oil level is low.

2. The viscosity of the oil is incorrect.

3. The pump has too much wear.

Problem 4: The oil pressure is low.

Probable causes:

1. The main relief valve opens at low oil pressure.

2. The pump has too much wear.

3. An O-ring seal in the system failed.

4. The control valve and valve spools have a large amount of wear.

Problem 5: The attachment moves while the control lever is in the HOLD position.

Probable causes:

1. The control valve and valve spools have a large amount of wear.

2. A piston seal in a cylinder has a large amount of wear.

3. There is a leak in a connection between the control valve and the cylinders.

4. A check valve is not closing because of dirt or because of a worn seat.

5. The control lever is not centered.

Problem 6: The attachment droops when the control lever is moved from the HOLD position to the LIFT position.

Probable cause:

1. The load check valve is not closing because the spring is weak or broken or because there is dirt or debris in the check valve.

Hydraulic System Pressure - Release

SMCS Code: 5050-553-PX

Show/hide table

NOTICE

Care must be taken to ensure that fludis are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

1. Move the machine to a smooth, horizontal location that is away from operating machines and away from personnel.

NOTE: Permit only one operator on the machine. Keep all other personnel away from the machine or in the operator's sight.

3. Engage the parking brake. Place wheel blocks in front of the wheels and behind the wheels.

NOTE: Do not stop the machine with the front of the machine off the ground unless this is required for a test. Lower the machine to the ground and stop the engine.

5. Install the steering frame lock pin so that the machine can not articulate.

6. To make sure all hydraulic pressure is released before any fitting, hose or component is loosened, tightened, removed or adjusted, perform the following steps:

a. Lower the bucket and/or attachments to the ground.

b. If the machine is equipped with an optional ride control system, with the engine running, turn the ride control switch to the ON position. Move the hydraulic control lever to the FLOAT position. This will relieve all of the hydraulic pressure in the ride control accumulator.

c. Stop the engine.

d. Move the hydraulic control lever several times through the full range of travel. This will release any pressure that may be present in the implement hydraulic system.

e. Move the STIC steering control several times in both directions to release any pressure in the steering system.

f. Depress the brake pedal at least eighty times to release any pressure in the brake accumulators.

g. Press and hold the breaker relief valve plunger to release any pressure in the hydraulic tank.

Tilt Circuit Manifolds
(1) Pressure test point (rod end circuit). (2) Pressure test point (head end circuit).

h. Connect a 27 600 kPa (4000 psi) gauge to pressure test point (1) on the tilt cylinder. If any pressure is registered on the gauge, move the control lever to all positions until all pressure is removed from the system.

i. Connect a 27 600 kPa (4000 psi) gauge to pressure test point (2) on the tilt cylinder. If any pressure is registered on the gauge, move the control lever to all positions until all pressure is removed from the system.

j. The pressure in the hydraulic system has now been released and lines or components can be removed.

k. Remove the test equipment.

Pump Flow - Test

SMCS Code: 5055-032-ON; 5055-032-TB

Reference: For additional information on the Specifications for the hydraulic pump, refer to Service Manual Module for Specifications for the machine that is being serviced.

This test is designed to determine whether a pump is operating within design parameters. Presently, only a bench test is available for this purpose. This test should be performed only if all cylinder cycle times are too slow.

For any pump test, the pump flow at 690 kPa (100 psi) will be larger than the flow at 6900 kPa (1000 psi) if the pump is operating at the same rpm. The pump flow is measured in L/min (US gpm).

The difference between the pump flow of two operating pressures is the flow loss.

NOTE: The values in the examples are not set values for any specific pump or for any specific pump condition. See the Specification for the pump flow of a new pump at 690 kPa (100 psi) and at 6900 kPa (1000 psi).

Table 1

Table 2

Flow loss that is expressed as a percentage of pump flow is used as a measure of pump performance.

Table 3

Table 4

Machine Test

Install a flow meter. Run the engine at high idle. Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in the formula in Table 5.

Table 5

Bench Test

If the test bench can be run at 6900 kPa (1000 psi) and at full pump rpm, use the formula in Table 5 to determine the percent of flow loss.

If the test bench cannot be run at 6900 kPa (1000 psi) or at full pump rpm, run the pump shaft at 1000 rpm. Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in the top portion of the formula in Table 6. For the bottom part of the formula, run the pump shaft at 2000 rpm. Measure the pump flow at 690 kPa (100 psi).

Table 6

Lift and Tilt Cylinder Drift - Check

SMCS Code: 5102-535-D9; 5104-535-D9

The drift rates will change according to many conditions (hydraulic oil temperature, type of bucket, load in the bucket, etc).

The values in the tables are for an empty bucket. Before you measure the drift on the cylinder rod, you must extend the cylinders at least five times. Then, check the oil temperature.

To check the lift circuit, lift the bucket to the maximum height and move the control lever to the HOLD position. Measure the drift distance and check the time with the following tables.

NOTE: The drift distances in the tables are for new machines.

To check the tilt circuit, lift the bucket to the maximum height and move the control lever to the HOLD position. Actuate the tilt circuit until the bucket is at the digging angle (almost level). Then, move the control lever to the HOLD position. Measure the drift distance and check the time with the following tables.

If the cylinder drift is too high, perform the following checks:

1. Check the makeup valves and the check valves in the main control valve.

2. Check the condition of the valve spools in the main control valve.

3. Check the piston seals in the cylinders.

4. Check the condition of the valve spool spring retainers and stem.

5. Check the main control valve mounting bolts for correct and even torque.

Reference: For information on tightening the main control valve mounting bolts, refer to Specifications, "Main Control Valve" for the machine that is being serviced.

Lift and Tilt Cylinder Speed - Check

SMCS Code: 5102-535-VF; 5104-535-VF

Start the engine and run the engine at high idle. Raise and lower the lift arms several times to get an increase in the temperature of the hydraulic oil. The hydraulic oil (SAE 10W) must be at a temperature of 65 ± 3°C (150 ± 5°F) in order to obtain accurate results.

NOTE: Perform all speed tests with the engine at high idle and with an empty bucket. If the machine is equipped with the optional ride control system, place the ride control switch in the OFF position.

The speeds in the following tables are those of a machine equipped with a standard bucket.

If the travel times are not correct, check the following conditions:

1. Check the engine high idle rpm.

2. Check the implement pump flow.

Reference: For information on the pump flow test, refer to Systems Operation, Testing and Adjusting, "Pump Flow - Test" for the machine that is being serviced.

3. Check the pressure settings of the relief valves.

4. Check the makeup valves in the main control valve.

5. Check the valve spools in the main control valve.

6. Check the piston seals in the cylinders.

Pilot System Pressure - Test

SMCS Code: 5050-032-PS

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

Location of the Pilot Oil Pressure Test Point
(1) Pressure test point for pilot system.

1. Attach the correct hose and pressure gauge to pressure test point (1).

2. Place wheel blocks in front of the wheels and behind the wheels.

3. Start and run the engine at low idle rpm. Disengage the parking brake. The pressure reading with the oil at normal operating temperature should be 3515 ± 70 kPa (510 ± 10 psi).

4. If the pressure is not correct, engage the parking brake and stop the engine.

5. Depress the brake pedal at least eighty times to release any pressure in the brake accumulators.

6. Move the hydraulic control lever to all positions to release any pressure in the implement pilot circuits.

7. Move the STIC steering control several times in both directions to release any pressure in the steering system.

8. Press and hold the breaker relief valve to release any pressure in the hydraulic tank.

Location of the Pilot Oil Pressure Reducing Valve
(2) Pilot oil pressure reducing valve.

Pilot Oil Pressure Reducing Valve
(2) Pilot oil pressure reducing valve. (3) Adjusting screw (internal).

9. Using an 8 mm (.3149 inch) allen wrench, turn adjusting screw (3) inside valve (2) clockwise to increase pressure and counterclockwise to decrease pressure.

10. Repeat Step 3.

11. If the pressure reading is correct, engage the parking brake and stop the engine. Remove the test equipment from test point (1). Place the protective cover over the test fitting.

12. If the pressure reading is not correct, engage the parking brake and stop the engine. Repeat Steps 5 through 10.

Relief Valve (Main) - Test and Adjust

SMCS Code: 5069-025; 5069-081

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

1. Start the engine. Run the engine at high idle. Operate the hydraulic control lever and move all the cylinders in order to increase the temperature of the hydraulic oil to normal operating temperature.

2. Stop the engine. Release the pressure from the hydraulic system.

Reference: For information on releasing the hydraulic system pressure, refer to Systems Operation, Testing and Adjusting, "Hydraulic System Pressure - Release" for the machine that is being serviced.

Location of the Main Relief Valve Pressure Test Point
(1) Pressure test point.

3. Attach the correct hose and pressure gauge to pressure test point (1).

4. Start the engine. Raise the lift arms to the maximum height.

NOTE: In the following step, do not keep the hydraulic control lever in the RAISE position for more than 5 seconds while the pressure is at the relief valve setting.

5. Increase the engine speed to high idle. Observe the pressure gauge and move the hydraulic control lever to the RAISE position.

6. The pressure setting of main relief valve (2) should be 20 685 ± 170 kPa (3000 ± 25 psi).

NOTE: If the pressure setting of the main relief valve is not at the specification, it will be necessary to adjust the valve.

7. Raise the lift arms and install the bucket control group safety pins.

Reference: For the information on installing the bucket control group safety pins, refer to Operation and Maintenance Manual, "Bucket Control Group Safety Pins" for the machine that is being serviced.

8. Stop the engine.

Main Control Valve in the Front Frame
(2) Main relief valve.

Main Relief Valve
(3) Adjusting screw. (4) Locknut.

9. Loosen locknut (4) on main relief valve (2). Turn adjusting screw (3) clockwise for an increase or counterclockwise for a decrease in the pressure setting of the main relief valve. Tighten locknut (4) to a torque of 50 ± 7 N·m (37 ± 5 lb ft).

10. Repeat Steps 5 through 9 until the pressure setting is correct.

11. When the pressure setting of main relief valve (2) is correct, lower the bucket to the ground and stop the engine. Remove the test equipment.

Relief Valve (Line) - Test and Adjust

SMCS Code: 5117-025-L9; 5117-081-L9

Show/hide table

Make sure all of the attachements have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

Tilt Cylinder Rod End Line Relief Valve

2. Stop the engine. Release the pressure from the hydraulic system.

Location of the Tilt Circuit Pressure Test Point (Rod End)
(1) Pressure test point.

3. Attach the correct hose and pressure gauge to pressure test point (1).

4. Start the engine. Raise the lift arms so that the bucket will be clear of the ground in the full DUMP position.

5. Move the bucket to the full DUMP position.

NOTE: In the following step, do not keep the hydraulic control lever in the DUMP position for more than 5 seconds while the pressure is at the relief valve setting.

6. Run the engine at low idle. Move and hold the hydraulic control lever in the DUMP position and observe the pressure gauge. The high reading on the pressure gauge is the pressure setting of the line relief valve.

7. The pressure setting of the tilt cylinder rod end line relief valve should be 13 790 ± 345 kPa (2000 ± 5 psi).

NOTE: If the pressure setting of the line relief valve is not at the specification, it will be necessary to adjust the valve.

8. Lower the bucket to the ground and stop the engine.

Main Control Valve
(2) Tilt cylinder rod end line relief valve. (3) Locknut. (4) Adjusting screw.

9. Loosen locknut (3) and turn adjusting screw (4) clockwise for an increase or counterclockwise for a decrease in the pressure setting of the line relief valve. Tighten locknut (3) to a torque of 25 ± 7 N·m (18 ± 5 lb ft).

10. Repeat Steps 4 through 9 until the pressure setting is correct.

11. When the pressure setting is correct, lower the bucket to the ground and stop the engine. Remove the test equipment.

Tilt Cylinder Head End Line Relief Valve

2. Stop the engine. Release the pressure from the hydraulic system.

Location of the Tilt Circuit Pressure Test Point (Head End)
(1) Pressure test point.

3. Attach the correct hose and pressure gauge to pressure test point (1).

NOTE: The main relief valve has a lower setting than the tilt cylinder head end line relief valve. To correctly set the tilt cylinder head end line relief valve, the main relief valve setting must be temporarily increased.

Location of the Main Relief Valve
(2) Adjusting screw. (3) Locknut. (4) Main relief valve.

4. Loosen locknut (3) on main relief valve (4). Turn adjusting screw (2) clockwise to temporarily increase the pressure setting of the main relief valve to 23 080 ± 345 kPa (3350 ± 50 psi). Tighten locknut (3) to a torque of 50 ± 7 N·m (37 ± 5 lb ft).

Reference: For information on setting the main relief valve, refer to Systems Operation, Testing and Adjusting, "Relief Valve (Main) - Test and Adjust" for the machine that is being serviced.

5. Start the engine. Raise the lift arms so that the bucket is clear of the ground.

6. Move the bucket to the full TILT BACK position.

NOTE: In the following step, do not keep the hydraulic control lever in the TILT BACK position for more than 5 seconds while the pressure is at the relief valve setting.

7. Run the engine at low idle. Move and hold the hydraulic control lever in the TILT BACK position and observe the pressure gauge. The high reading on the pressure gauge is the pressure setting of the line relief valve.

8. The pressure setting of the tilt cylinder head end line relief valve should be 22 065 ± 345 kPa (3200 ± 50 psi).

NOTE: If the pressure setting of the line relief valve is not at the specification, it will be necessary to adjust the valve.

9. Lower the bucket to the ground and stop the engine.

Main Control Valve
(5) Tilt cylinder head end line relief valve. (6) Locknut. (7) Adjusting screw.

10. Loosen locknut (6) and turn adjusting screw (7) clockwise for an increase or counterclockwise for a decrease in the pressure setting of the line relief valve. Tighten locknut (6) to a torque of 25 ± 7 N·m (18 ± 5 lb ft).

11. Repeat Steps 5 through 10 until the pressure setting is correct.

12. When the pressure setting is correct, lower the bucket to the ground and stop the engine. Remove the test equipment.

13. Reset the main relief valve to the correct pressure setting.

Reference: For information on resetting the main relief valve, refer to Systems Operation, Testing and Adjusting, "Relief Valve (Main) - Test and Adjust" for the machine that is being serviced.

Relief Valve (Lift Circuit) - Test and Adjust

SMCS Code: 5117-025-LQ; 5117-081-LQ

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

NOTE: The lift circuit relief valve has a higher pressure setting than the main relief valve. The recommended method to test the relief valve is to remove the valve from the machine and use a test bench to test and adjust the valve.

1. Release the pressure from the hydraulic system.

Location of the Lift Circuit Relief Valve
(1) Lift circuit relief valve.

2. Remove lift circuit relief valve (1) from the manifold on the main control valve.

3. Install the relief valve into the test manifold and attach to a test bench.

4. Test the pressure setting of the lift circuit relief valve. The pressure setting of the lift circuit relief valve should be 31 025 ± 345 kPa (4500 ± 50 psi).

Lift Circuit Relief Valve
(2) Adjusting screw. (3) Locknut.

5. If the pressure setting of lift circuit relief valve (1) is not correct, loosen locknut (3). Turn adjusting screw (2) clockwise for an increase or counterclockwise for a decrease in the pressure setting of the relief valve.

6. When the pressure setting is correct, tighten locknut (3). Remove the relief valve and test manifold from the test bench.

7. Remove the relief valve from the test manifold and install it in the manifold in the main control valve. Tighten the relief valve to a torque of 62 ± 2 N·m (46 ± 1.5 lb ft).

Float Sequence Valve - Test and Adjust

SMCS Code: 5119-025; 5119-081

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

Operator's Station
(1) Lift arm positioner switch. (2) Ride control switch.

1. Move lift arm positioner switch (1) and ride control switch (2) (if equipped) to the OFF position.

2. Start the engine and put the bucket in a partial dump position. Lower the lift arms until the front wheels just clear the ground.

3. Move the hydraulic control lever to the FLOAT position. The front wheels should return to the ground.

4. If the front wheels return to the ground before FLOAT is selected, the float sequence valve pressure setting is too low. If the front wheels do not return to the ground when FLOAT is selected, the pressure setting is too high.

5. Stop the engine. Release the pressure from the hydraulic system.

Float Sequence Valve Pressure Test Point
(3) LOWER pilot oil line (to float sequence valve).

6. Attach a suitable tee-fitting, test nipple, hose and the correct gauge to bucket LOWER pilot oil line (3).

7. Start the engine. Move the hydraulic control lever gradually to the FLOAT position and look at the test gauge.

8. The pressure setting for the float sequence valve to be activated should be 1930 ± 70 kPa (280 ± 10 psi).

NOTE: If the pressure setting of the float sequence valve is not at the specification, it will be necessary to adjust the valve.

9. Raise the lift arms and install the bucket control group safety pins.

10. Stop the engine.

Location of the Float Sequence Valve
(4) Float sequence valve adjusting screw.

11. To adjust the float sequence valve pressure setting loosen the locknut. Turn adjusting screw (4) clockwise for an increase or counterclockwise for a decrease in the pressure setting of the float sequence valve. Tighten the locknut.

12. Repeat Steps 7 through 11 until the pressure setting is correct.

13. When the pressure setting of float sequence valve (4) is correct, lower the bucket to the ground and stop the engine. Remove the test equipment.

NOTE: An optional method for setting the float sequence valve is to remove the valve from the machine and use a test bench to test and adjust the valve.

Lift Arm Positioner - Adjust

SMCS Code: 5112-025

Show/hide table

Use caution to avoid possible personal injury when adjusting the lift arm positioner.
Install the bucket control group safety pins and stop the engine prior to making any adjustments.
Engage the parking brake and block the wheels to prevent sudden movement of the machine.

Keep unauthorized personnel off the machine.

Operator's Station
(1) Lift arm positioner switch.

1. Move lift arm positioner switch (1) to the ON position.

Operator's Station
(2) Hydraulic control lever.

2. With the engine running, move hydraulic control lever (2) to the TILT BACK position until the bucket is fully tilted back.

3. Raise the lift arms to the full height. Move the hydraulic control lever to the FLOAT position to lower the lift arms. The lift arm positioner should bring the lift arms and bucket to a controlled stop at the correct height for digging.

Illustration B

4. Illustration A shows the correct setup height. Dimension (A) should be 300 ± 25 mm (11.8 ± 1 inch).

Front Loader Frame
(3) Magnetic switch. (4) Bolts.

5. If dimension (A) is greater than 325 mm (12.8 inch), adjust magnetic switch (3) downwards. If dimension (A) is less than 275 mm (10.8 inch), adjust the magnetic switch upwards.

6. To adjust magnetic switch (3), loosen two bolts (4) that fasten the switch to the frame and move the switch to the desired position. Tighten bolts (4).

7. Repeat Steps 3 through 6 until dimension (A) is correct.

Illustration B

8. To check the final setup height, repeat Step 3. Tilt the bucket forward until the cutting edge of the bucket touches the ground. The bucket should be in the digging position, as shown in Illustration B. A final adjustment may be necessary to obtain the correct digging position.

9. Finally, tighten bolts (4) to a torque of 47 ± 9 N·m (35 ± 7 lb ft).

Ride Control Accumulator - Test and Charge

SMCS Code: 5077-045-R6; 5077-081-R6

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

Dry nitrogen is the only gas approved for use in the accumulators. A charging of oxygen gas in an accumulator will cause an explosion. An explosion can be eliminated by using nitrogen gas cylinders with standard CGA (Compressed Gas Association, Inc.) No. 580 connectors. When nitrogen gas is ordered, make sure to order the cylinders with CGA No. 580 connectors.

Do not rely on color codes or other methods of identification to tell the difference between nitrogen and oxygen cylinders. In any application, never use an adapter to connect your nitrogen charging group to a valve outlet used on both nitrogen, oxygen, or other gas cylinders. BE SURE YOU USE DRY NITROGEN (99.8% purity).

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

Nitrogen Charging Procedure

Location of the Ride Control Accumulator

Location of the Ride Control Switch

Nitrogen Charging Group
(1) Needle valve. (2) Pressure gauge. (3) Quick disconnect coupling (male). (4) "T" handle. (5) Chuck. (6) Pressure gauge. (7) Connection to nitrogen cylinder valve. (8) Pressure regulating screw. (9) Regulator Assembly. (10) Quick disconnect coupling (female). (11) Quick disconnect coupling (male). (12) Hose assembly. (13) Quick disconnect coupling (female).

1. Move the machine to level ground.

3. Engage the parking brake. Place wheel blocks in front of the wheels and behind the wheels.

4. Install the steering frame lock pin so that the machine can not articulate.

5. Start the engine. Keep the engine running during the following steps. This will ensure that a flow of pilot oil is available to shift the diverter valve spool when the ride control switch is moved to the ON position.

6. Move the hydraulic control lever to the FLOAT position. Turn the ride control switch to the ON position.

7. Remove the guard over the nitrogen gas charge valve.

8. Remove the cap on the nitrogen gas charge valve.

NOTE: Turn "T" handle (4) all the way out (counterclockwise) before attaching the chuck to the accumulator gas valve.

9. Attach gas chuck (5) to the accumulator gas charge valve.

10. Join male and female quick disconnect couplings (3) and (13). Route the open end of hose assembly (12) away from the work area.

NOTE: Opening "T" handle (4) and valve (1) and raising the lift arms, causes the gas in the accumulator to exhaust. Ensure the gas outlet (open end of the hose assembly) is pointed away from any personnel.

11. Open needle valve (1) and turn "T" handle (4) on gas chuck (5) all the way in (clockwise).

12. Raise the lift arms to the maximum height. Hold the hydraulic control lever in the RAISE position for five seconds. This will release all of the compressed gas from the accumulator and ensure the accumulator piston is all the way up.

13. Close needle valve (1).

14. Lower the lift arms until the bucket rests on the ground and move the hydraulic control lever to the FLOAT position.

15. Attach quick disconnect coupling (female) (10) to quick disconnect coupling (male) (11).

16. Attach the nitrogen charging group to the nitrogen cylinder. Adjust screw (8) to set the pressure on gauge (6) to 2070 ± 35 kPa (300 ± 5 psi). The pressure given is at 21 degrees C (70 degrees F) ambient. Refer to the following chart for other temperatures.

NOTE: If the machine has been in use for some time, the ambient temperature of the accumulator may be different from the outside air temperature. In this case, use the temperature of the accumulator in the following chart.

17. Open needle valve (1) and measure the length of time it takes pressure gauge (2) to read the charge pressure.

NOTE: The charge time should take only 10 to 20 seconds. If the gauge instantly reads the correct charge pressure, the compressed gas was not relieved correctly from the gas chamber in Steps 1 through 13. Go back to Step 1 and repeat the procedure until the gas has been completely relieved from the system.

18. Turn the nitrogen gas off, but leave the line connected. This will ensure that the accumulator piston is bottomed out and that the gas chamber is completely full of nitrogen gas.

19. Turn the ride control switch to the OFF position. Raise the lift arms and hold the control lever in the RAISE position for five seconds. This will make the system reach and maintain the implement relief valve setting.

20. The gas pressure gauge should indicate implement hydraulic system relief pressure. If a lower pressure is indicated at this time, the accumulator has not been fully charged and the procedure must be started again.

21. Lower the bucket to the ground. Watch the pressure gauge, and move the ride control switch to the ON position. The gas pressure should drop immediately.

NOTE: An empty bucket will have a tendency to raise. This action indicates the ride control function is operating correctly.

22. If the gas pressure has not dropped to the charge pressure, go back to Step 1 and repeat the procedure.

23. Remove the nitrogen charging group and replace the protective cap on the gas charge valve assembly.

24. Replace the guard over the gas charge valve.

NOTE: If the accumulator needs to be replaced, follow Steps 1 through 14 in "Nitrogen Charging Procedure". This will release all of the compressed gas from the accumulator gas chamber. The accumulator can now be removed from the machine.

Rebuilt or New Accumulator Nitrogen Charging Procedure

NOTE: It is necessary to remove all the air from the nitrogen end of the accumulator. When the accumulator is new or rebuilt, put approximately 1.9 Liters (2 quarts) of SAE 10W hydraulic oil in the nitrogen end of the accumulator. This oil will be used to help remove air from the nitrogen end of the accumulator and also to put lubricant at the top seal of the accumulator piston.

1. Attach gas chuck (5) to the accumulator gas charge valve. Join male and female quick disconnect couplings (3) and (13). Put the open end of hose assembly (12) in a container.

2. Open needle valve (1) and turn "T" handle (4) on gas chuck (5) all the way in (clockwise).

3. With the accumulator mounted in an upright position move the accumulator piston fully to the nitrogen end of the accumulator.

Accumulator (Typical Example)

4. As the accumulator piston moves to the top of the accumulator, the air and then the oil will be pushed out of the nitrogen end of the accumulator through the hose assembly into the container. When the oil flow stops, the nitrogen end of the accumulator will be free of air.

5. Close needle valve (1) completely. Allow any residual oil that may be in the hose assembly to drain into the container.

6. Attach quick disconnect coupling (female) (10) to quick disconnect coupling (male) (11).

7. Attach the nitrogen charging group to the nitrogen cylinder. Adjust screw (8) to set the pressure on gauge (6) to 2070 ± 35 kPa (300 ± 5 psi). The pressure given is at 21 degrees C (70 degrees F) ambient. Refer to the chart in "Nitrogen Charging Procedure" for other temperatures.

8. Open needle valve (1). Turn the nitrogen gas off and remove the nitrogen charging group.

9. Install the protective cap on the gas charge valve. Install the guard over the gas charge valve.

10. Install the charged accumulator in the machine.

11. Recheck the accumulator nitrogen charge by referring to the procedure "Checking the Nitrogen Charge in the Accumulator".

Checking the Nitrogen Charge in the Accumulator

1. Move the machine to level ground and engage the parking brake. Place wheel blocks in front of the wheels and behind the wheels.

2. Install the steering frame lock pin so that the machine can not articulate.

3. With the engine running, move the ride control switch to the ON position.

4. Lower the bucket to the ground. Move the hydraulic control lever to the FLOAT position. This will relieve all of the hydraulic pressure in the accumulator.

5. Stop the engine.

6. Remove the guard over the nitrogen gas charge valve on the accumulator.

7. Remove the cap from the nitrogen gas charge valve.

8. Close needle valve (1).

Parts from Nitrogen Charging Group
(1) Needle valve. (2) Pressure gauge. (3) Quick disconnect coupling (male). (4) "T" handle. (5) Chuck.

NOTE: Turn "T" handle (4) all the way out (counterclockwise) before attaching the chuck to the accumulator gas valve.

9. Attach gas chuck (5) to the accumulator gas charge valve.

10. Turn "T" handle (4) completely in (clockwise) and read the pressure on gauge (2). The pressure must be inside the tolerances shown in the chart.

11. If the pressure on gauge (2) is too high, slowly open valve (1) to lower the pressure.

12. If the pressure on gauge (2) is too low, charge the accumulator. Refer to "Nitrogen Charging Procedure".

Testing the Ride Control Diverter Valve

The following procedure is used to determine whether the ride control diverter valve is operating correctly. Perform this test after the accumulator is charged.

1. Start the engine.

2. Move the ride control switch to the OFF position.

3. Place the bucket in the full DUMP position. Lift the front wheels off the ground by moving the hydraulic control lever to the LOWER position.

4. Move the ride control switch to the ON position. The front wheels should lower to the ground.

If the wheels do not lower to the ground, the ride control diverter spool has not shifted to the ON position. The following conditions are probable causes:

* The ride control switch has failed.

* The solenoid coil on the ride control diverter valve has failed.

* The cartridge valve in the ride control diverter valve has failed.

* The spool valve in the ride control diverter valve has failed.

* There is a blockage in the pilot circuit to the ride control diverter valve.

Ride Control Road Test

NOTE: The pressures in the ride control accumulator charging procedure are recommended for machines with a standard bucket. For machines with heavy buckets, the nitrogen pressure may need to be increased to keep the accumulator piston from striking the stop during normal roading while the ride control system is activated. Raising the nitrogen pressure will result in a stiffer ride.

1. Put a typical load in the bucket.

2. Move the ride control switch to the ON position.

3. Drive the machine over a rough road surface. If the machine bounces too much or the accumulator piston is striking the stop, the nitrogen precharge pressure must be increased.

4. Increase the nitrogen precharge pressure by 345 kPa (50 psi) and perform the road test again. Refer to "Nitrogen Charging Procedure".

NOTE: Only add enough nitrogen to achieve a suitable ride for the machine's typical payload.

Ride Control Relief Valve - Test and Adjust

SMCS Code: 5117-025-R6; 5117-081-R6

Show/hide table

Block the wheels and install the steering frame lock.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

NOTE: The ride control relief valve protects the ride control accumulator and other components in the ride control system. The ride control relief valve has a higher pressure setting than the main relief valve. The recommended method to test the relief valve is to remove the valve from the machine and use a test bench to test and adjust the valve.

1. Move the machine to level ground and engage the parking brake. Place wheel blocks in front of the wheels and behind the wheels.

2. Raise the lift arms and install the bucket control group safety pins.

3. With the engine running, move the ride control switch to the ON position.

4. Move the hydraulic control lever to the FLOAT position. This will relieve all of the hydraulic pressure in the ride control accumulator.

5. Stop the engine.

Location of the Ride Control Relief Valve and Manifold
(1) Ride control relief valve. (2) Locknut. (3) Adjusting screw. (4) Manifold.

6. Remove ride control relief valve (1) and manifold (4) as an assembly from the ride control diverter valve.

7. Connect the ride control relief valve and manifold to a test bench.

8. Test the pressure setting of the ride control relief valve. The pressure setting of the ride control relief valve should be 31 025 ± 345 kPa (4500 ± 50 psi).

9. If the pressure setting of ride control relief valve (1) is not correct, loosen locknut (2). Turn adjusting screw (3) clockwise for an increase or counterclockwise for a decrease in the pressure setting of the relief valve.

10. When the pressure setting is correct, tighten locknut (2). Remove the relief valve and manifold from the test bench.

11. Install the ride control relief valve and manifold on the ride control diverter valve.