Bench Test Procedure for Hydraulic Piston Pumps {0738, 5050, 5070} Caterpillar

Bench Test Procedure for Hydraulic Piston Pumps {0738, 5050, 5070}

Usage:

Vibratory Soil Compactor: CP56B (S/N: 4851-UP; MP61-UP; P561-UP; 4381-UP; 5081-UP; LHC1-UP; M5P1-UP); CP68B (S/N: 5101-UP; 6841-UP; CM61-UP; P681-UP; 4891-UP; LCF1-UP; SDT1-UP); CP74B (S/N: 4911-UP; 5121-UP; P741-UP; 7441-UP; CP71-UP; L7B1-UP; M7B1-UP); CS56B (S/N: 4841-UP; M561-UP; S561-UP; 4371-UP; 5071-UP; L8H1-UP; M4M1-UP); CS66B (S/N: CS61-UP; S661-UP; 4871-UP); CS68B (S/N: CS81-UP; M681-UP; 4881-UP; 4391-UP; 5091-UP; MBF1-UP; MMS1-UP); CS74B (S/N: 4901-UP; 4411-UP; C741-UP; CS41-UP; LCB1-UP; E7E1-UP; B7M1-UP); CS76B (S/N: 4921-UP; CB71-UP; L9H1-UP); CS78B (S/N: 4431-UP; 4931-UP; 5131-UP; M781-UP; S781-UP; L8C1-UP; M8M1-UP)

Introduction

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Table 1
Revision	Summary of Changes in REHS3626
10	Updated effectivity.
09	Added new Vibratory Soil Compactor serial number prefixes CP7, M78, and 513 to document.
08	Updated effectivity.
07	Added new Pipelayer serial number prefixes P72, P73, TEC, CB2, ZAC, and DLW to document.
	Added new Vibratory Soil Compactor serial number prefixes 507, 508, 509, 510, 512, MP6, M56, M68, B7M. CM6, and C74 to document.
	Added part number 432-6067 Piston Pump Gp to document.
	Added part number 453-3634 Piston Pump Gp to document.
06	Updated Tables 3 and 4.
06	Added new Vibratory Soil Compactor serial number prefixes P56, P68, P74, CS5, S56, S66, CS8, CS4, CB7, and S78 to document.

© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Caterpillar Dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law. Information contained in this document is considered Caterpillar: Confidential Yellow.

This Special Instruction includes test procedures for piston pumps. This Special Instruction also provides specifications. The technician should have a good understanding of hydraulic piston pumps. The technician should be educated in the operation of the hydraulic test bench. The test benches in this document are available through the Caterpillar Service Tool Division. Gather all necessary tooling before you need to hook up the pump. Some of the required tooling appears in a table at the end of this document. There are many possible variations of tooling that could be used. Not every possible variation can be listed.

For questions or additional information concerning this guideline, submit a feedback form in the Service Information System website. To address an urgent need, please use the following to relay your request to Caterpillar Repair Process Engineering:

Cat Dealer Technical Communicator
Dealer Solution Network
Cat Technical Representative
Knowledge Network (online)

Canceled Part Numbers and Replaced Part Numbers

This document may not include all Canceled part numbers and replaced part numbers. Use NPR on SIS for information about Canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Safety

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Illustration 1	g02139237

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Personal injury or death can result from improperly checking for a leak.
Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing 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.

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Pump test pressures in this guideline may exceed the normal operating range of the hydraulic test hoses utilized when connecting the tested pump to the test bench. However, the order of magnitude of these pressures is significantly below the burst strength of the Caterpillar "XT6" product.
High pressure oil can escape through improperly assembled hoses and fittings. High pressure oil can also escape through poorly maintained hoses and fittings. High pressure oil may also leak through hose that has become damaged over the life of the hose due to the pressure levels that occur during test bench operation.
Personal injury or death can result from improper hose & fitting inspection or improper hose replacement procedures. Escaping fluid under pressure can penetrate body tissue causing serious injury, and possible death.

Thoroughly inspect all testing hoses, fittings, and quick disconnects prior to any testing operation. Check the assembly date tag or hose assembly log date for a hose life indicator. Replace all Test Bench hoses at a minimum of every 2 years or earlier if the hose or fittings appear to be damaged.

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Note: Do not attempt to make any pump adjustments while the pump is on the machine. This document was designed to test pumps using a hydraulic test bench.

Summary

This procedure is specific to the type of pump and the type of control. Refer to the test specifications and the tooling at the end of this document.

Note: A paper copy of this document may not be the latest version. Go to the Service Information System (SIS) to view the latest version.

References

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Table 2
References
Media Number	Title
REHS1761	Required Tooling for Bench Testing Hydraulic Components
SEBF8810	Hydraulic Pump, Motor, and Cylinder Bench Test Procedure Reference Manual
SEHS8892	Operating Instructions for Caterpillar 1U-9400 Series Hydraulic Test Center
NEHS0563	Tool Operating Manual for 9U-5000 Series Hydraulic Test Bench

Connections for the Caterpillar Hydraulic Test Center

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Illustration 2	g01063311
Connections for the Test Center (1) Flow control for discharge (2) "F3" flow meter inlet (3) "F4" flow meter inlet (4) Oil supply from the auxiliary pump (5) "F3" outlet for the flow meter with flow limiter (6) Oil supply (7) Load sensing pressure (8) Signal pressure (9) "F4" outlet for the flow meter (10) Return to tank (11) Connections for case drain (12) Oil supply

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Illustration 3	g01063312
Control and Gauges for the Test Center (13) meter for speed and torque (14) Gauge for signal pressure (15) Control for signal pressure (16) Pressure gauge for auxiliary pump (17) Auxiliary pump flow (18) "F3" discharge pressure gauge (19) "F3" discharge flow (20) "F4" discharge pressure gauge (21) "F4" discharge flow (22) Auxiliary pump flow control (23) "F3" margin pressure (24) "F3" Load control for discharge pressure (25) "F4" Load control for discharge pressure

Connections for the Caterpillar Hydraulic Test Bench

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Illustration 4	g01063314
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

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Illustration 5	g01093468
Connections for the Test Bench (28) "Flow meter 2" loop (29) "Flow meter 1" loop (30) "Flow meter 2" outlet (31) Signal pressure line (32) "Flow meter 2" inlet (33a) "Flow meter 1" outlet (33b) Auxiliary oil supply "outlet" (34) Auxiliary oil supply "inlet" (35) "Flow meter 1" inlet

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Illustration 6	g01063316
Control and Gauges for the Test Bench (36) Auxiliary pump pressure (37) Signal pressure (38) Control for signal pressure (39) "Flow meter 1" discharge pressure (40) Control for auxiliary pump pressure (41) "Flow meter 2" discharge pressure (42) Auxiliary pump flow control (43) "Flow meter 2" discharge flow (44) Discharge flow for auxiliary pump (45) "Flow meter 1" discharge flow (46) "Flow meter 1" load control (47) Speed and direction control (48) "Flow meter 2" load control

Port Locations

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Illustration 7	g02792107
Typical port locations and adjustments. (49) Clamping screw for hydraulic zero (rear pump) (50) Proportional solenoid B (rear pump) (51) Adjustment screw for hydraulic zero (rear pump) (52) Gauge port for stroking pressure (X1, rear pump) (53) Vent port for case (port R) (54) Gauge port for charge pressure (port PS) (55) Adjustment screw for pressure override valve (POR, high-pressure cut) (56) Gauge port for stroking pressure (X2, front pump) (57) Proportional solenoid A (front pump) (58) Vent port for case (port R) (59) Clamping screw for hydraulic zero adjustment (front pump) (60) Adjustment screw for hydraulic zero (front pump) (61) Proportional solenoid B (front pump) (62) Gauge port for stroking pressure (X1, front pump) (63) Pressure override valve (POR) pressure resolvers (64) Case drain (port T2) (65) Discharge port B (front pump) (66) Discharge port A (front pump) (67) Discharge port B (rear pump) (68) Discharge port A (rear pump) (69) Case drain (port T2) (70) Gauge port for stroking pressure (X2, rear pump) (71) Proportional solenoid A (rear pump) (72) Case drain (port T1) (73) Adjustment screw for mechanical zero (front pump) (74) Gauge port for discharge pressure B (MB, front pump) (75) To brake release (port YST, can also measure charge pressure here) (76) Adjustment screw for mechanical zero (rear pump) (77) Gauge port for discharge pressure B (MB, rear pump) (78) Case drain (port T1) (79) Inlet for charge oil (port G) (80) Sequence valve solenoid (interlock) (81) Gauge port for discharge pressure A (MA, rear pump) (82) Crossover relief valves (four total) (83) Adjustment screw for port plate timing (84) Gauge port for discharge pressure A (MA, front pump) (85) Charge relief valve

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Illustration 8	g02792792
Hydraulic schematic (50) Proportional solenoid B (rear pump) (52) Gauge port for stroking pressure (X1, rear pump) (53) Vent port for case (port R) (54) Gauge port for charge pressure (port PS) (55) Adjustment screw for pressure override valve (POR, high-pressure cut) (56) Gauge port for stroking pressure (X2, front pump) (57) Proportional solenoid A (front pump) (58) Vent port for case (port R) (61) Proportional solenoid B (front pump) (62) Gauge port for stroking pressure (X1, front pump) (63) Pressure override valve (POR) pressure resolvers (64) Case drain (port T2) (65) Discharge port B (front pump) (66) Discharge port A (front pump) (67) Discharge port B (rear pump) (68) Discharge port A (rear pump) (69) Case drain (port T2) (70) Gauge port for stroking pressure (X2, rear pump) (71) Proportional solenoid A (rear pump) (72) Case drain (port T1) (74) Gauge port for discharge pressure B (MB, front pump) (75) To brake release (port YST, can also measure charge pressure here) (77) Gauge port for discharge pressure B (MB, rear pump) (78) Case drain (port T1) (79) Inlet for charge oil (port G) (80) Sequence valve solenoid (interlock) (81) Gauge port for discharge pressure A (MA, rear pump) (82) Crossover relief valves (four total) (84) Gauge port for discharge pressure A (MA, front pump) (85) Charge relief valve

9U-5902 Rectifier Block

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Illustration 9	g02796710
9U-5902 Rectifier Block Connections

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Illustration 10	g02796712
9U-5902 Rectifier Block Schematic (86) high-pressure port (87) high-pressure outlet (88) low-pressure inlet (89) high-pressure port

9U-5893 Heat Exchanger

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Illustration 11	g02796714
9U-5893 Heat Exchanger Connections (90) Inlet from flow meter loop (91) Outlet to rectifier block (92) Water inlet (93) Water outlet

198-4240 Electric Pressure Gauge Group

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Illustration 12	g02796716
198-4240 Electric Pressure Gauge Group Connections (94) Pressure gauge (95) Red transducer 34500 kPa (5000 psi) (96) Blue transducer 3450 kPa (500 psi)

Note: The accuracy of the mechanical zero position and the hydraulic zero position is crucial. The use of the 198-4240 Electric Pressure Gauge Group is Highly recommended.

Set Up for the Front Pump

Note: A power supply is required to operate the solenoid. The power supply should be capable of delivering 0 A to 1.5 A with an infinite setting in that range.

Install pressure taps in the following test ports:
(54) Gauge port for charge pressure (port PS)
(56) Gauge port for stroking pressure (X2, front pump)
(62) Gauge port for stroking pressure (X1, front pump)
(74) Gauge port for discharge pressure B (MB, front pump)
(84) Gauge port for discharge pressure A (MA, front pump)
Connect power supply to front Proportional solenoid A (57) or B (61).
Connect power supply to Sequence valve solenoid (80) if pump is equipped with breaking valve.
Note: Be sure to use XT-6ES rated hydraulic hose.
Connect front pump discharge ports B (65) and A (66) to the 9U-5902 Rectifier Block high-pressure ports (86) and (89).
Connect the 9U-5902 Rectifier Block high-pressure outlet (87) to the flow meter inlet on the test bench.
Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (90) .
Connect the 9U-5893 Heat Exchanger outlet (91) to the low-pressure return (88) on the 9U-5902 Rectifier Block.
Connect two red transducers 34500 kPa (5000 psi) (95) or two 40000 kPa (5800 psi) 8T-0860 Pressure Gauges to the front pump Gauge ports for discharge pressure B (74) and A (84) .
Connect a hose from rear discharge port B (67) to rear discharge port A (68). Connect the discharge ports to isolate the rear pump. At this point the rear pump will not be tested.
Connect a hose from Inlet for charge oil (79) to the auxiliary oil outlet on the test bench.
Fill the pump case with oil. Pour oil directly into Case drain port (78) until the case is full. Direct flow from Case drain port (78) to test bench reservoir.
Install a pressure gauge on Gauge port for charge pressure (54).
Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump. The correct direction of rotation will also be in the Test Specifications. The direction of rotation is viewed from the input shaft end. Visually check the pump for proper rotation.

Test Procedure for the Front Pump

The ISO contamination rating of the hydraulic oil in the test bench should be at least 16/13. The oil in the test bench should be one of the following.

SAE 10W at 50 °C (122 °F) or
Mobil DTE-11 at 46 °C (115 °F)

Adjustment for Mechanical Zero Position for the Front Pump

Turn the load control on the test bench completelyclockwise to control the pump discharge pressure. Start rotating the pump at the value in Step 2 of the Test Specifications. Be sure to sustain charge pump flow to Inlet for charge oil (79). Connect a hose between the front ports for the stroking pressure X2 (56) and X1 (62). If the mechanical zero adjustment is incorrect, a discharge pressure higher than the charge pressure may occur.
Note: Increase signal current to Sequence valve solenoid (80) until braking valve is activated. This will allow the charge pressure to be read at gauge port for charge pressure (54). This will also allow the pump to produce flow when proportional solenoids A and B receive current later in this document.
Note: If the mechanical zero is unable to be set correctly, the hydraulic zero may be too far out of adjustment. In this case it will be necessary to set the hydraulic zero within 300 kPa (43.5 psi) using the procedure "Adjustment for Hydraulic Zero Position for the Front Pump". Try to set the mechanical zero again. This may need to repeated several times to correctly achieve the mechanical zero adjustment. After the mechanical zero is set, proceed to "Adjustment for Hydraulic Zero Position for the Front Pump". For the final hydraulic zero adjustment, set the hydraulic zero within 21 kPa (3 psi)
Turn Adjustment screw for mechanical zero (front pump) (73) clockwise. Continue to turn until pressure increases on the Gauge port discharge pressure B (74) or the Gauge port for discharge pressure A (84). Mark the position of Adjustment screw for mechanical zero (front pump) (73).
Turn Adjustment screw for mechanical zero (front pump) (73) counterclockwise until pressure increases on Gauge ports for discharge pressure B (74) or A (84). Mark the position of the Adjustment screw for mechanical zero (front pump) (73).
A mark should be placed halfway between position one and position two. Turn Adjustment screw for mechanical zero (front pump) (73) to the midpoint of both marks. There should be less than a 34.5 kPa (5 psi) pressure differential between Gauge ports for discharge pressure B (74) and A (84).
Stop rotating the pump. Turn the load control on the test bench for pump discharge pressure counterclockwise. Allow the discharge pressure of the pump to decrease. Disconnect red transducers or pressure gauges from front Gauge ports for discharge pressure B (74) and A (84).

Adjustment for Hydraulic Zero Position for the Front Pump

Connect two blue transducers 3450 (500 psi) (96) or connect two 6000 kPa (870 psi) 8T-0856 Pressure Gauges to front Gauge ports for stroking pressure X2 (56) and X1 (62).
Start rotating the pump to the value listed in Step 2 of the Test Specifications. Be sure to sustain charge pump flow to Inlet for charge oil (79). Turn the load control for the pump discharge pressure completelyclockwise. This will allow pump discharge pressure to increase in the following steps.
Note: Increase signal current to Sequence valve solenoid (80) until braking valve is activated. This will allow the charge pressure to be read at gauge port for charge pressure (54). This will also allow the pump to produce flow when proportional solenoids A and B receive current later in this document.
Loosen Clamping screw for hydraulic zero adjustment (front pump) (59). Adjust Adjustment screw for hydraulic zero (front pump) (60) until the pressure at the front Gauge ports for stroking pressure X2 (56) and X1 (62) differ by less than 21 kPa (3 psi). Tighten Clamping screw for hydraulic zero adjustment (front pump) (59). Recheck hydraulic zero pressures. Repeat Step 3 if necessary.
Note: Do not turn Adjustment screw for hydraulic zero (front pump) (60) more than 90 degrees in either direction.
Turn the load control for the pump discharge pressure counterclockwise. This will allow pump discharge pressure to decrease. Stop rotating the pump and allow pump pressure to dissipate. Disconnect the pressure gauges that are connected to the front Gauge ports for stroking pressure X2 (56) and X1 (62).

Testing the Front Pump Control

Note: The steps in the procedure correlate with the steps under the Test Specifications according to your specific part number.

The contamination level of the hydraulic oil in the test bench should be ISO 16/13 or better. The oil in the test bench should be one of the following.

SAE 10W at 50 °C (122 °F) or
Mobil DTE-11 at 46 °C (115 °F)

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Illustration 13	g01143449

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Illustration 14	g01143458

Start rotating the pump according to the RPM in Step 1 of the Test Specifications. Pumps without a charge pump will require auxiliary charge flow according to the value in Step 1 of the Test Specifications. Verify the flow rates and listen for abnormal noise. Verify that all connections are secure. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around control valves. Check the Gauge port for charge pressure (54). Compare the actual charge pressure with the value in Step 1 of the Test Specifications. If the charge pressure is not within the Test Specifications, replace the charge relief valve. Run the pump for at least 5 minutes to raise the temperature of the oil and purge the system of air.
Note: Increase signal current to Sequence valve solenoid (80) until braking valve is activated. This will allow charge pressure to be read at Gauge port for charge pressure (54). This will also allow the pump to produce flow when proportional solenoids A and B receive current later in this document.
Note: The front pump has two separate proportional solenoids. Test one solenoid at a time, then repeat steps 2 through 4 of the Test Procedure to test the other solenoid.
Slowly increase the pump RPM to the value in Step 2 of the Test Specifications. Increase the signal current to front Proportional solenoid A (57) or B (61) according to the value in Step 2 of the Test Specifications. This is the point of upstroke of the pump. The pump operation or the control of the signal pressure may not be operating properly if the actual discharge flow is not correct.
Note: Some flow meters may not be able to read discharge flows at this level. Slowly increase signal current to a value that is higher than the value in Step 2 of the Test Specifications if the flow meter does not register the flow. Continue until the flow begins to register.
Increase the signal current to front Proportional solenoid A (57) or B (61) to the value in Step 3 of the Test Specifications. The pump should be fully upstroked (maximum displacement). Record actual pump flow. The pump or the control for the proportional solenoid valve may not be mechanically feasible if the actual flow is not equal to the value in Step 3 of the Test Specifications.
Increase pump discharge pressure to the value in Step 4 of the Test Specifications. Measure pump leakage at this point. Calculate the total loss. The pump may not be mechanically feasible if the total loss is higher than the allowable value in Step 4 of the Test Specifications.
Subtract the discharge flow that was recorded in Step 4 of the Test Procedure from the discharge flow that was recorded in Step 3 of the Test Procedure to find the total loss.
Example: Step 3 flow 162 L/min (42.8 US gpm) - "Step 4 flow" 158 L/min (41.7 US gpm) = "total loss" 4 L/min (1.1 US gpm). The "max. allowable loss" is 7.2 L/min (1.9 US gpm).
The pump in the example is acceptable because the actual total loss is less than the maximum allowable loss.

Repeat Steps 2 through 4 of the Test Procedure by connecting the power supply to the opposite front Proportional solenoid A (57) or B (61).

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Reduce RPM, all pressures, and all currents to zero. Proceed to "Set Up for the Rear Pump"

Set Up for the Rear Pump

Note: A power supply is required to operate the solenoid. The power supply should be capable of delivering 0 A to 1.5 A with an infinite setting in that range.

Install pressure taps in the following test ports:
(54) Gauge port for charge pressure (port PS)
(52) Gauge port for stroking pressure (X1, rear pump)
(70) Gauge port for stroking pressure (X2, rear pump)
(77) Gauge port for discharge pressure B (MB, rear pump)
(81) Gauge port for discharge pressure A (MA, rear pump)
Connect power supply to rear Proportional solenoid B (50) or A (71).
Connect power supply to Sequence valve solenoid (80) if pump is equipped with breaking valve.
Note: Be sure to use XT-6ES rated hydraulic hose.
Connect rear pump Discharge ports B (67) and A (68) to the 9U-5902 Rectifier Block high-pressure ports (86) and (89).
Connect the 9U-5902 Rectifier Block high-pressure outlet (87) to the flow meter inlet on the test bench.
Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (90) .
Connect the 9U-5893 Heat Exchanger outlet (91) to the low-pressure return (88) on the 9U-5902 Rectifier Block.
Connect two red transducers 34500 kPa (5000 psi) (95) or two 40000 kPa (5800 psi) 8T-0860 Pressure Gauges to the rear pump Gauge ports for discharge pressure B (77) and A (81) .
Connect a hose from front Discharge port B (65) to front Discharge port A (66). Connect the discharge ports to isolate the front pump. At this point the front pump will not be tested.
Connect a hose from Inlet for charge oil (79) to the auxiliary oil outlet on the test bench.
Fill the pump case with oil. Pour oil directly into Case drain port (78) until the case is full. Direct flow from Case drain port (78) to test bench reservoir.
Install a pressure gauge on Gauge port for charge pressure (54).
Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump. The correct direction of rotation will also be in the Test Specifications. The direction of rotation is viewed from the input shaft end. Visually check the pump for proper rotation.

Test Procedure for the Rear Pump

The ISO contamination rating of the hydraulic oil in the test bench should be at least 16/13. The oil in the test bench should be one of the following.

SAE 10W at 50 °C (122 °F) or
Mobil DTE-11 at 46 °C (115 °F)

Adjustment for Mechanical Zero Position for the Rear Pump

Turn the load control on the test bench completely clockwise to control the pump discharge pressure. Start rotating the pump at the value in Step 2 of the Test Specifications. Be sure to sustain charge pump flow to Inlet for charge oil (79). Connect a hose between the rear Gauge ports for stroking pressure X1 (52) and X2 (70). If the mechanical zero adjustment is incorrect, a discharge pressure higher than the charge pressure may occur.
Note: Increase signal current to Sequence valve solenoid (80) until braking valve is activated. This will allow the charge pressure to be read at Gauge port for charge pressure (54). This will also allow the pump to produce flow when proportional solenoids A and B receive current later in this document.
Note: If the mechanical zero is unable to be set correctly, the hydraulic zero may be too far out of adjustment. In this case it will be necessary to set the hydraulic zero within 300 kPa (43.5 psi) using the procedure "Adjustment for Hydraulic Zero Position for the Rear Pump". Try to set the mechanical zero again. This may need to repeated several times to correctly achieve the mechanical zero adjustment. After the mechanical zero is set, proceed to "Adjustment for Hydraulic Zero Position for the Rear Pump". For the final hydraulic zero adjustment, set the hydraulic zero within 21 kPa (3 psi).
Turn Adjustment screw for mechanical zero (rear pump) (76) clockwise. Continue to turn until pressure increases on the Gauge port for discharge pressure B (77) or the Gauge port for discharge pressure A (81). This pressure may be seen on Gauge port for discharge pressure B (77) or Gauge port for discharge pressure A (81). Mark the position of Adjustment screw for mechanical zero (rear pump) (76).
Turn Adjustment screw for mechanical zero (rear pump) (76) counterclockwise until pressure increases on Gauge ports for discharge pressure B (77) or A (81). Mark the position of Adjustment screw for mechanical zero (rear pump) (76).
A mark should be placed halfway between position one and position two. Turn Adjustment screw for mechanical zero (rear pump) (76) to the midpoint of both marks. There should be less than a 34.5 kPa (5 psi) pressure differential between pump Gauge ports for discharge pressure B (77) and A (81).
Stop rotating the pump. Turn the load control on the test bench for pump discharge pressure counterclockwise. Allow the discharge pressure of the pump to decrease. Disconnect red transducers or pressure gauges from rear Gauge ports for discharge pressure B (77) and A (81).

Adjustment for Hydraulic Zero Position for the Rear Pump

Connect two blue transducers 3450 (500 psi) (96) or connect two 6000 kPa (870 psi) 8T-0856 Pressure Gauges into rear Gauge ports for stroking pressure X1 (52) and X2 (70).
Start rotating the pump to the value listed in Step 1 of the Test Specifications. Be sure to sustain charge pump pressure to Inlet for charge oil (79). Turn the load control for the pump discharge pressure completely clockwise. This will allow pump discharge pressure to increase in the following steps.
Note: Increase signal current to Sequence valve solenoid (80) until braking valve is activated. This will allow the charge pressure to be read at Gauge port for charge pressure (54). This will also allow the pump to produce flow when proportional solenoids A and B receive current later in this document.
Loosen Clamping screw for hydraulic zero adjustment (rear pump) (49). Adjust Adjustment screw for hydraulic zero adjustment (rear pump) (51) until the pressure at the rear Gauge ports for stroking pressure X1 (52) and X2 (70) differ by less than 21 kPa (3 psi). Tighten the Clamping screw for hydraulic zero adjustment (rear pump) (49). Recheck hydraulic zero pressures. Repeat Step 3 if necessary.
Note: Do not turn Adjustment screw for hydraulic zero adjustment (rear pump) (51) more than 90 degrees in either direction.
Turn the load control for the pump discharge pressure counterclockwise. This will allow pump discharge pressure to decrease. Stop rotating the pump and allow pump pressure to dissipate. Disconnect the pressure gauges that are connected to the rear Gauge ports for stroking pressure X1 (52) and X2 (70).

Testing the Rear Pump Control

Note: The steps in the procedure correlate with the steps under the Test Specifications according to your specific part number.

The contamination level of the hydraulic oil in the test bench should be ISO 16/13 or better. The oil in the test bench should be one of the following.

SAE 10W at 50 °C (122 °F) or
Mobil DTE-11 at 46 °C (115 °F)

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Illustration 15	g01143449

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Illustration 16	g01143458

Start rotating the pump according to the RPM in Step 1 of the Test Specifications. Pumps without a charge pump will require auxiliary charge flow according to the value in Step 1 of the Test Specifications. Verify the flow rates and listen for abnormal noise. Verify that all connections are secure. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around control valves. Check Gauge port for charge pressure (54). Compare the actual charge pressure with the value in Step 1 of the Test Specifications. If the charge pressure is not within the Test Specifications, replace the charge relief valve. Run the pump for at least 5 minutes to raise the temperature of the oil and purge the system of air.
Note: Increase signal current to Sequence valve solenoid (80) until braking valve is activated. This will allow charge pressure to be read at Gauge port for charge pressure (54). This will also allow the pump to produce flow when proportional solenoids A and B receive current later in this document.
Note: The rear pump has two separate proportional solenoids. Test one solenoid at a time, then repeat Steps 2 through 4 of the Test Procedure to test the other solenoid.
Slowly increase the pump RPM to the value in Step 2 of the Test Specifications. Increase the signal current to rear Proportional solenoid B (50) or A (71) according to the value in Step 2 of the Test Specifications. This is the point of upstroke of the pump. The pump operation or the control of the signal pressure may not be operating properly if the actual discharge flow is not correct.
Note: Some flow meters may not be able to read discharge flows at this level. Slowly increase signal current to a value that is higher than the value in Step 2 of the Test Specifications if the flow meter does not register the flow. Continue until the flow begins to register.
Increase the signal current to rear Proportional solenoid B (50) or A (71) to the value in Step 3 of the Test Specifications. The pump should be fully upstroked (maximum displacement). Record actual pump flow. The pump or the control for the proportional solenoid valve may not be mechanically feasible if the actual flow is not equal to the value in Step 3 of the Test Specifications.
Increase pump discharge pressure to the value in Step 4 of the Test Specifications. Measure pump leakage at this point. Calculate the total loss. The pump may not be mechanically feasible if the total loss is higher than the allowable value in Step 4 of the Test Specifications.
Subtract the discharge flow that was recorded in Step 4 of the Test Procedure from the discharge flow that was recorded in Step 3 of the Test Procedure to find the total loss.
Example: Step 3 flow 162 L/min (42.8 US gpm) - "Step 4 flow" 158 L/min (41.7 US gpm) = "total loss" 4 L/min (1.1 US gpm). The "max. allowable loss" is 7.2 L/min (1.9 US gpm).
The pump in the example is acceptable because the actual total loss is less than the maximum allowable loss.

Repeat Steps 2 through 4 of the Test Procedure by connecting the power supply to the opposite rear Proportional solenoid B (50) or A (71).

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Reduce RPM, all pressures, and all currents to zero. Proceed to "Set Up for Adjusting the POR".

Set Up for Adjusting the POR

Note: Two 9U-5893 Heat Exchangers are required for this step.

Note: There is only one Pressure Override Valve (POR). The POR is shared by the front and rear pump.

Note: A power supply is required to operate the solenoid. The power supply should be capable of delivering 0 A to 1.5 A with an infinite setting in that range.

Install pressure taps in the following test ports:
(54) Gauge port for charge pressure
(62) Gauge port for stroking pressure (X1, front pump).
Connect power supply to front Proportional solenoid B (61) and rear Proportional solenoid A (71).
Connect power supply to Sequence valve solenoid (80) if pump is equipped with breaking valve.
Note: Be sure to use XT-6ES rated hydraulic hose.
Connect front pump Discharge port A (66) to the flow meter inlet on the test bench.
Connect flow meter outlet on the test bench to the 9U-5893 Heat Exchanger inlet (90).
Connect the 9U-5893 Heat Exchanger outlet (91) to front Discharge port B (65)
Connect rear pump Discharge ports B (67) and A (68) to the 9U-5902 Rectifier Block high-pressure ports (86) and (89).
Connect the 9U-5902 Rectifier Block high-pressure outlet (87) to the flow meter inlet on the test bench.
Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (90) .
Connect the 9U-5893 Heat Exchanger outlet (91) to the low-pressure return (88) on the 9U-5902 Rectifier Block.
Connect a hose from Inlet for charge oil (79) to the auxiliary oil outlet on the test bench.
Fill the pump case with oil. Pour oil directly into Case drain port (78) until the case is full. Direct flow from Case drain port (78) to test bench reservoir.
Install a pressure gauge on the Gauge port for charge pressure (54).
Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump. The correct direction of rotation will also be in the Test Specifications. The direction of rotation is viewed from the input shaft end. Visually check the pump for proper rotation.

Procedure to Adjust the POR

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Pump test pressures in this guideline may exceed the normal operating range of the hydraulic test hoses utilized when connecting the tested pump to the test bench. However, the order of magnitude of these pressures is significantly below the burst strength of the Caterpillar XT6 product.
High pressure oil can escape through improperly assembled hoses and fittings. High pressure oil can also escape through poorly maintained hoses and fittings. High pressure oil may also leak through hose that has become damaged over the life of the hose due to the pressure levels that occur during test bench operation.
Personal injury or death can result during adjustment of the high pressure relief valve if recommended hose maintenance practices are not followed. Escaping fluid under pressure can penetrate body tissue causing serious injury, and possible death.

Adjustment of the high pressure cut or pressure override valve shall only be performed when the pump is operating at a zero discharge pressure condition. Continuation of the pump test procedure can be resumed when this high pressure adjustment is completed.

Note: Two 9U-5893 Heat Exchangers are required for this step.

Note: Be sure to sustain charge pump flow to Inlet for charge oil (79).

Run the pump at 500 RPM briefly to warm oil and check for leaks and unusual noises. Increase speed to 1500 RPM.
Energize front Proportional solenoid B (61) and rear Proportional solenoid A (71) to 1500 mA.
Adjust the load control on the test bench until the rear pump output pressure is between 4000 kPa (580 psi) and 8000 kPa (1160 psi).
The POR should be set at 45000 kPa (6525 psi).
1. To check the POR set point, turn the load control on the test bench for the front pump completely clockwise being sure not to exceed 45500 kPa (6525 psi)
2. If the discharge pressure for the front pump exceeds the 45000 kPa (6525 psi) POR set point, reduce RPM, all pressures, and all currents to zero before making adjustments in Step 4.c of the Test Procedure.
3. Turn Adjustment screw for pressure override valve (POR, High-Pressure Cut) (55) counter-clockwise 3 turns. Repeat Steps 4.a and 4.b until the POR is set at 45000 kPa (6525 psi) when the load control on the test bench for the front pump is turned completelyclockwise. Record the stroking pressure at Gauge port for stroking pressure (X1, front pump) (62). This value will be used for reference in Step 6 of "Procedure to Adjust the Port Plate Timing"

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Reduce RPM, all pressures, and all currents to zero. Proceed to "Set Up for Adjusting the POR".

Set Up for Adjusting the Port Plate Timing

Note: Two 9U-5893 Heat Exchangers are required for this step.

Note: A power supply is required to operate the solenoid. The power supply should be capable of delivering 0 A to 1.5 A with an infinite setting in that range.

Install pressure taps in the following test ports:
(54) Gauge port for charge pressure
(70) Gauge port for stroking pressure (X2, rear pump).
Connect power supply to front Proportional solenoid B (61) and rear Proportional solenoid A (71).
Connect power supply to Sequence valve solenoid (80) if pump is equipped with breaking valve.
Note: Be sure to use XT-6ES rated hydraulic hose.
Connect rear pump Discharge port A (68) to the flow meter inlet on the test bench.
Connect flow meter outlet on the test bench to the 9U-5893 Heat Exchanger inlet (90).
Connect the 9U-5893 Heat Exchanger outlet (91) to rear Discharge port B (67)
Connect front pump Discharge ports B (65) and A (66) to the 9U-5902 Rectifier Block high-pressure ports (86) and (89).
Connect the 9U-5902 Rectifier Block high-pressure outlet (87) to the flow meter inlet on the test bench.
Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (90) .
Connect the 9U-5893 Heat Exchanger outlet (91) to the low-pressure return (88) on the 9U-5902 Rectifier Block.
Connect a hose from Inlet for charge oil (79) to the auxiliary oil outlet on the test bench.
Fill the pump case with oil. Pour oil directly into Case drain port (78) until the case is full. Direct flow from Case drain port (78) to test bench reservoir.
Install a pressure gauge on Gauge port for charge pressure (54).
Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump. The correct direction of rotation will also be in the Test Specifications. The direction of rotation is viewed from the input shaft end. Visually check the pump for proper rotation.

Procedure to Adjust the Port Plate Timing

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Pump test pressures in this guideline may exceed the normal operating range of the hydraulic test hoses utilized when connecting the tested pump to the test bench. However, the order of magnitude of these pressures is significantly below the burst strength of the Caterpillar XT6 product.
High pressure oil can escape through improperly assembled hoses and fittings. High pressure oil can also escape through poorly maintained hoses and fittings. High pressure oil may also leak through hose that has become damaged over the life of the hose due to the pressure levels that occur during test bench operation.
Personal injury or death can result during adjustment of the high pressure relief valve if recommended hose maintenance practices are not followed. Escaping fluid under pressure can penetrate body tissue causing serious injury, and possible death.

Note: Two 9U-5893 Heat Exchangers are required for this step.

Note: Perform following steps only after setting POR correctly for the front pump.

Note: Be sure to sustain charge pump flow to Inlet for charge oil (79).

Run the pump at 500 RPM briefly to warm oil and check for leaks and unusual noises. Increase speed to 1500 RPM.
Energize front Proportional solenoid B (61) and rear Proportional solenoid A (71) to 1500 mA.
Adjust the load control on the test bench until the front pump output pressure is between 4000 kPa (580 psi) and 8000 kPa (1160 psi).
Turn the load control on the test bench for the rear pump completely clockwise to block flow.
Check the port plate timing by comparing Gauge port for stroking pressure (X2, rear pump) (70) to the recorded value of the stroking pressure at Gauge port for stroking pressure (X1, front pump) (62) in Step 4.c of "Procedure to Adjust the POR".
Note: Reduce RPM, all pressures, and all currents to zero before making adjustments in Step 6 of the Test Procedure
Adjust Adjustment screw for port plate timing (83) until stroking pressure at Gauge port for stroking pressure (X2, rear pump) (70) equals the recorded value of the stroking pressure at Gauge port for stroking pressure (X1, front pump) (62) in Step 4.c of "Procedure to Adjust the POR".

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Reduce RPM, all pressures, and all currents to zero. Drain the oil from the pump and remove the pump from the test bench. Cap or plug all ports.

Test Specifications

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Table 3
Part Number	351-8597⁽¹⁾
Rotation	Clockwise
Step	1	2	3	4
RPM	800	1500	1500	1500
Signal Current mA	0	500	1500	1500
Discharge Pressure kPa (psi)	2500 (363)⁽²⁾	2500 (363)⁽²⁾	2500 (363)⁽²⁾	23000 (3336)
Discharge Flow liter per minute (gpm)	0	1 (0.26)	97 (25.6)	97 (25.6)
Pump Loss Efficiency liter per minute (gpm)	Subtract the actual Step 4 Discharge Flow from the actual Step 3 Discharge Flow. This is the Total Loss.			7 (1.8) Max
Charge Pressure kPa (psi)	2500 (363)	2500 (363)	2500 (363)	2500 (363)
Charge Flow liter per minute (gpm)	40 (10.5) (External)	75 (20) (External)	75 (20) (External)	75(20) (External)

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⁽¹⁾	Canceled replaced by 458-7912
⁽²⁾	Discharge pressure equals charge pressure

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Table 4
Part Number	458-7912
Rotation	Clockwise
Step	1	2	3	4
RPM	800	1500	1500	1500
Signal Current mA	0	500	1500	1500
Discharge Pressure kPa (psi)	2500 (363)⁽¹⁾	2500 (363)⁽¹⁾	2500 (363)⁽¹⁾	23000 (3336)
Discharge Flow liter per minute (gpm)	0	1 (0.26)	97 (25.6)	97 (25.6)
Pump Loss Efficiency liter per minute (gpm)	Subtract the actual Step 4 Discharge Flow from the actual Step 3 Discharge Flow. This is the Total Loss.			7 (1.8) Max
Charge Pressure kPa (psi)	2500 (363)	2500 (363)	2500 (363)	2500 (363)
Charge Flow liter per minute (gpm)	40 (10.5) (External)	75 (20) (External)	75 (20) (External)	75(20) (External)

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⁽¹⁾	Discharge pressure equals charge pressure

Test Bench Tooling

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Table 5
Part Number	Mounting Flange	Drive Adapter	Split Flange	Flange Adapter	Case Drain	Stroking Pressure Ports	Charge Pressure Supply Port	Charge Pressure Gauge Port
351-8597	1U-9127	1U-9394	8T-9403	9U-7438	1-1/16-12 STOR	9/16-18 STOR	7/8-14 STOR	3/4-16 STOR
458-7912	1U-9127	1U-9394	8T-9403	9U-7438	1-1/16-12 STOR	9/16-18 STOR	7/8-14 STOR	3/4-16 STOR