Bench Test Procedure for Hydraulic Piston Pumps {5070} Caterpillar

Pipelayer

PL83 (S/N: CB21-UP; DLW1-UP)

PL87 (S/N: TEC1-UP; ZAC1-UP)

Rotary Drill

MD6310 (S/N: DLK1-UP; DLZ1-UP)

Track-Type Tractor

D6N (S/N: MG51-UP; GB61-UP)

D6R2 (S/N: PPP1-UP; SSS1-UP; TTT1-UP)

Introduction

© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission bay 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 Dealer Service Tools. 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 web site. To address an urgent need, use the following to relay your request to Caterpillar Repair Process Engineering:

• Cat dealer Technical Communicator

• Dealer Solution Network

• Caterpillar Technical Representative

• Knowledge Network (online)

Canceled Part Numbers and Replaced Part Numbers

This document does not include 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

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

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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.

Summary

This procedure is specific to the type of pump and the type of control. Refer to the Test Specifications and the Tooling sections 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

Connections for the Caterpillar Hydraulic Test Center

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" inlet for the flow meter with flow limiter (6) "F3"outlet for the flow meter with pressure control (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

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

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

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

Illustration 6	g01063316
Control and Gauges for the Test Bench (36) Auxiliary oil supply pressure (37) Signal pressure (38) Control for signal pressure (39) "Flow meter 1" discharge pressure (40) Control for auxiliary oil supply pressure (41) "Flow meter 2" discharge pressure (42) Auxiliary oil supply 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

Pump Illustrations

Illustration 7	g03821365
Port locations (49) Adjustment screw for mechanical zero (50) Electrical connector for displacement control (51) Adjustment screw for pressure cutoff valve (52) Adjustment screw for crossover relief valve (53) Pilot pressure inlet (54) Hydrostatic bypass adjustment (55) Charge pressure inlet (from filter) (56) Gauge port for charge pressure (57) Charge pressure inlet (58) Adjustment screw for crossover relief valve (59) Suction port (60) Adjustment screw for charge relief valve (61) Case drain port (62) Gauge port for stroking pressure (63) Adjustment screw for hydraulic zero (64) Air bleed port (65) Gauge port for stroking pressure (66) Electrical connector for displacement control (67) Discharge port (68) Gauge port for discharge pressure (69) Case drain port (70) Gauge port for discharge pressure (71) Charge pressure outlet (to filter) (72) Discharge port (73) Gauge port for high pressure

Illustration 8	g03821366
Hydraulic Schematic (49) Adjustment screw for mechanical zero (50) Electrical connector for displacement control (51) Adjustment screw for pressure cutoff valve (52) Adjustment screw for crossover relief valve (53) Pilot pressure inlet (54) Hydrostatic bypass adjustment (55) Charge pressure inlet (from filter) (56) Gauge port for charge pressure (57) Charge pressure inlet (58) Adjustment screw for crossover relief valve (59) Suction port (60) Adjustment screw for charge relief valve (61) Case drain port (62) Gauge port for stroking pressure (64) Air bleed port (65) Gauge port for stroking pressure (66) Electrical connector for displacement control (67) Discharge port (68) Gauge port for discharge pressure (69) Case drain port (70) Gauge port for discharge pressure (71) Charge pressure outlet (to filter) (72) Discharge port (73) Gauge port for high pressure

9U-5902 Rectifier Block

Illustration 9	g03791901
9U-5902 Rectifier Block Connections (74) High-pressure port (75) High-pressure outlet (76) High-pressure port (77) Low-pressure inlet

Illustration 10	g03791921
9U-5902 Rectifier Block Schematic (83) High-pressure port (84) High-pressure outlet (85) High-pressure port (86) Low-pressure inlet

9U-5893 Heat Exchanger

Illustration 11	g03791933
9U-5893 Heat Exchanger Connections (87) Inlet (88) Outlet (89) Water inlet (90) Water outlet

Pump Setup

An electrical power supply is required to operate the solenoids on this pump. The power supply must deliver 0 mA to 1600 mA with an infinite setting in that range.

1. Connect suction port (59) to the auxiliary oil supply on the test bench using 1" XT-6ES hose.

2. Connect charge pressure outlet (71) to charge pressure inlet (55) using 1" XT-6ES hose.

3. Connect pump discharge ports (67) and (71) to the 9U-5902 Rectifier Block high-pressure ports (74) and (76) using 1" XT-6ES hose.

4. Connect the 9U-5902 Rectifier Block outlet (75) to the flow meter inlet on the test bench using 1" XT-6ES hose.

5. Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (78) using 1" XT-6ES hose.

6. Connect the 9U-5398 Heat Exchanger outlet (79) to the 9U-5902 Rectifier Block low-pressure return (77) using 1" XT-6ES hose.

7. Connect an electrical power supply to electrical connector for displacement control (50) or (66) to operate the displacement control.

8. Install appropriately sized pressure gauges on the gauge port for charge pressure (56).

9. Install appropriately sized pressure gauges on the gauge ports for discharge pressure (68) and (70).

10. Fill the pump case with oil. Pour oil directly into case drain port (61) until the case is full.

11. Vent the case drain port (61) to the atmosphere. Make sure that the case drain flow is directed into the sump.

12. 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.

Adjustment for Mechanical Zero Position

1. 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 1 of the Test Specifications. Be sure to sustain charge pump flow to suction port (59) in Steps 1 through 5 of the Adjustment for Mechanical Zero Position. Vent the ports for the stroking pressure (62) and (65) to the atmosphere. This will equalize the pressure on the servo spool. Install pressure gauges on ports for discharge pressure (68) and (70). Turn the load control on the test bench completely clockwise to control the pump discharge pressure. If the mechanical zero adjustment is incorrect, a discharge pressure higher than the charge pressure may occur.

   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". Try to set the mechanical zero again. This may need to repeated several times to achieve the mechanical zero adjustment. After the mechanical zero is set, proceed to "Adjustment for Hydraulic Zero Position". For the final hydraulic zero adjustment, set the hydraulic zero within 21 kPa (3 psi)

2. Turn the adjustment screw for the mechanical zero (49) clockwise. Continue to turn until a pressure of 200 psi above charge pressure is achieved. This pressure may be seen on the gauge port for discharge pressure (68) or gauge port for discharge pressure (70). Mark the position of the adjustment screw for the mechanical centering (49).

3. Turn adjustment screw for the mechanical centering (49) counterclockwise until pressure increases on gauge ports for discharge pressure (68) or (70). Mark the position of the adjustment screw for the mechanical centering (49).

4. A mark should be placed halfway between position one and position two. Turn the adjustment screw for the mechanical centering (49) 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 (68) and (70).

5. 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 pressure gauges from ports (68) and (70).

Adjustment for Hydraulic Zero Position

1. Connect two blue transducers 3450 (500 psi) or connect two 6000 kPa (870 psi) 8T-0856 Pressure Gauges into both gauge ports for stroking pressure (62) and (65).

2. Start rotating the pump to the value listed in Step 1 of the Test Specifications. Turn the load control for the pump discharge pressure clockwise. This will allow pump discharge pressure to increase in the following steps.

3. Adjust the adjustment screw for hydraulic zero (63) until the pressure at the gauge ports for the stroking pressure (62) and (65) differ by less than 21 kPa (3 psi).

   Note: Do not turn the adjustment screw for the hydraulic zero (63) more than 90 degrees in either direction.

4. 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 gauge ports for stroking pressure (62) and (65).

Test Procedure

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)

1. 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 the charge pressure (56). 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 adjust the charge relief valve. Adjust the charge relief valve by turning the adjustment screw (60) clockwise or counterclockwise accordingly. Run the pump for at least 5 minutes to raise the temperature of the oil and purge the system of air.

2. This step will verify beginning of pump stroke.

   Slowly increase the pump input speed to the value in Step 2 of the Test Specifications. Increase the signal current to solenoid (50) or (66) according to the value in Step 2 of the Test Specifications. This is the initial 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.

3. This step will verify end of pump stroke.

   Increase the signal current to displacement control (50) or (66) to the value in Step 3 of the Test Specifications. The pump should be fully upstroked. 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.

4. This step will verify volumetric efficiency of the pump.

   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 4 flow 162 L/min (42.8 US gpm) - "Step 3 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.

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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.

5. This step will verify the setting of the crossover relief valves.

   Note: This step should only be performed if the fittings, hoses, and test bench are rated for the pressures given in Step 5 of the"Test Specifications". Skip to Step 6 if your fittings, hoses, or test bench are not rated for the pressures in Step 5 of the"Test Specifications". Crossover relief valves can be test while the pump is installed on the machine.

   Turn the adjustment screw for pressure cutoff (51) completely clockwise. Slowly increase discharge pressure to the value in Step 5 of the"Test Specifications". Verify that the pump cannot build pressure greater that the value in Step 5 of the"Test Specifications". If the discharge pressure is not within specification, adjust the adjustment screw for crossover relief valve (52) or (57) depending on which side of the pump is being tested. If the crossover relief valve is not adjustable, it may need to be replaced.

6. This step will verify the setting of the pressure cutoff valve.

   Decrease the discharge pressure to the value in Step 6 of the"Test Specifications". The pump should destroke and flow should decrease to the value in Step 6 of the"Test Specifications". If the pump does not destroke, turn the adjustment screw for pressure cutoff (51) until the pump destrokes at the pressure in Step 6 of the"Test Specifications".

7. This step will verify function of the hydrostatic drive bypass valve.

   Reduce discharge pressure and input speed to zero. Turn the hydrostatic bypass adjustment (54) counterclockwise until it reaches the adjacent adjustment stop. Increase input speed and discharge pressure to the values in Step 7 of the"Test Specifications". Flow should be zero even when the pump is stroked. If flow has not decreased significantly, the hydrostatic drive bypass valve may not be functioning properly. Reduce input speed and discharge pressure to zero. Turn the hydrostatic bypass adjustment (54) completely clockwise when finished with this step.

Repeat Steps 2 through 7 and apply displacement control current to the opposite displacement control solenoid (66) or (50) to test the opposite side of the pump.

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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 all pressures, electrical currents, and input speeds to zero. Remove the component from the test bench. Drain oil from the pump. Cap or plug all ports.

Test Specifications

Tooling