Bench Test Procedure for Hydraulic Piston Pumps {5070} Caterpillar

Wheel Loader

994K (S/N: MM91-UP; MRK1-UP; SMX1-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 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 web site. 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

• Caterpillar Technical Representative

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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

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. This procedure should be used with the specific test specifications and tooling at the end of this Special Instruction.

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	g03885861
Port locations and adjustments (49) Adjustment screw for minimum displacement for front pump (50) Adjustment screw for margin pressure for front pump (51) Adjustment screw for pressure cutoff for front pump (52) Adjustment screw for pressure cutoff for rear pump (53) Adjustment screw for margin pressure for rear pump (54) Adjustment screw for minimum displacement for rear pump (55) Pressure port for load sensing for rear pump (56) Case drain port (57) Suction port (58) Case drain port (59) Bearing flushing port for rear pump (60) Case drain port (61) Discharge port for rear pump (62) Pressure port for load sensing front pump (63) Discharge port for front pump (64) Case drain port (65) Bearing flushing port for front pump (66) Case drain port (67) Adjustment screw for maximum displacement for front pump (68) Gauge port for control pressure for front pump (69) Gauge port for discharge pressure for front pump (70) Gauge port for stroking pressure for front pump (71) Gauge port for suction pressure (72) Gauge port for stroking pressure for rear pump (73) Gauge port for discharge pressure for rear pump (74) Gauge port for control pressure for rear pump (75) Adjustment screw for maximum displacement for rear pump (76) Case drain port

Illustration 8	g03885862
Hydraulic schematic (49) Adjustment screw for minimum displacement for front pump (50) Adjustment screw for margin pressure for front pump (51) Adjustment screw for pressure cutoff for front pump (52) Adjustment screw for pressure cutoff for rear pump (53) Adjustment screw for margin pressure for rear pump (54) Adjustment screw for minimum displacement for rear pump (55) Pressure port for load sensing for rear pump (56) Case drain port (57) Suction port (58) Case drain port (59) Bearing flushing port for rear pump (60) Case drain port (61) Discharge port for rear pump (62) Pressure port for load sensing front pump (63) Discharge port for front pump (64) Case drain port (65) Bearing flushing port for front pump (66) Case drain port (67) Adjustment screw for maximum displacement for front pump (68) Gauge port for control pressure for front pump (69) Gauge port for discharge pressure for front pump (70) Gauge port for stroking pressure for front pump (71) Gauge port for suction pressure (72) Gauge port for stroking pressure for rear pump (73) Gauge port for discharge pressure for rear pump (74) Gauge port for control pressure for rear pump (75) Adjustment screw for maximum displacement for rear pump (76) Case drain port

4C-3582 Load Sensing Valve

Illustration 9	g03887996
4C-3582 Load Sensing Valve

Illustration 10	g03887997
4C-3582 Load Sensing Valve

Illustration 11	g03887999
Schematic for 4C-3582 Load Sensing Valve (77) Outlet port (78) Adjustment for the discharge flow (79) Inlet port (80) High-pressure port (81) Adjustment for the discharge pressure (82) Low-pressure port (83) Pressure port for load sensing

Illustration 12	g03888028
4C-3582 Load Sensing Valve and 1U-5796 Pressure Differential Gauge Group (77) To the flow meter on the test bench (78) Adjustment knob for discharge flow (79) From the pump discharge port (80) To the high side of the differential gauge (81) Load control for pump discharge pressure (82) To the low side of the differential gauge (83) Pressure port for load sensing (84) Pressure differential gauge group (85) To the low side of the load sensing group (86) To the high side of the load sensing valve

Pump Setup

Note: The component being tested is made up of two pumps: front pump and rear pump. Only one pump will be tested at a time, the other pump will be in stand by. Only connect one pump to the load sensing valve at a time. The other pump will be connected to a flow meter and directed back to tank.

1. Mount the pump with suction port (57) downward. Connect suction port (57) to the test bench oil supply.

2. Connect a 1 inch high pressure XT-6 ES hose from the pump discharge port (61) or (63) to inlet port (80) on the 4C-3582 Load Sensing Valve.

3. Connect a 1 inch high pressure XT-6 ES hose from the outlet port (77) on the 4C-3582 Load Sensing Valve to the flow meter inlet on the test bench.

4. Connect a 6D-7726 Hose Assembly to the pressure port for load sensing (83). Connect the other end of 6D-7726 Hose Assembly to the pressure port for load sensing (55) or (62) on the pump.

   Note: Do not use 1U-5754 Hose Assembly for load sensing signal lines. The flow rate through these hoses will not compensate for possible leakage through the control valve. Erratic readings with result.

5. Connect the 1U-5796 Pressure Differential Gauge Group (84) to the high-pressure port (79) and low-pressure port (82) on the 4C-3582 Load Sensing Valve. The port marked "hi" (66) on the 1U-5796 Pressure Differential Gauge Group should be hooked up to the port marked "hi" (59) on the 4C-3582 Load Sensing Valve. The port marked "low" (65) on the 1U-5796 Pressure Differential Gauge Group should be hooked up to the port marked "low" (62) on the 4C-3582 Load Sensing Valve.

   Note: The ports marked "low" (62) and "sense line" (63) on the 4C-3582 Load Sensing Valve are reading the same pressure.

6. Connect a 1 inch high pressure XT-6 ES hose from the other pump discharge port (61) and (63) to a flow meter inlet on the test bench. Connect a 1 inch high pressure XT-6 ES hose from the flow meter outlet to tank.

7. Purge all air from the suction line. Carefully loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction hose.

8. Fill pump case with oil. Pour oil directly into case drain port (60) until the case is full.

9. Install flow meter to case drain port (60). Route the discharge back to tank.

10. Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pumps. 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

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

The hydraulic oil in the test bench should meet an ISO rating of 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)

Illustration 13	g01141988

1. This step will verify assembly and connections.

   Start rotating the pump according to the input speed in Step 1 of the Test Specifications. Listen for abnormal noise. Verify flow from the pump. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around the control valve.

   Run the pump for at least 5 minutes in order to raise the temperature of the oil and purge the system of air.

2. This step will verify maximum displacement setting of the pump.

   Slowly increase the input speed to the value in Step 2 of the test specifications. If the actual flow is less than the value in Step 2 of the test specifications, adjustment is necessary. To decrease flow, loosen the locknut. Turn the adjustment screw for maximum displacement (67) or (75) clockwise. To increase flow, turn the adjustment screw for maximum displacement (67) or (75) counterclockwise.

3. This step will verify the margin pressure setting of the pump.

   Adjust the discharge flow by using the 4C-3582 Load Sensing Valve. Bench circuitry will be used to limit the flow when using a 1U-9400 Test Center. Adjust the discharge flow according to the values in Step 3 of the Test Specifications using adjustment for discharge flow (78). Adjust the discharge pressure according to the values in Step 3 of the test specifications using adjustment for discharge pressure (81). Adjust the screw for margin pressure (50) or (53) to the value in Step 3 of the test specifications. The margin pressure will be displayed on the 1U-5796 Pressure Differential Gauge (84).

   Note: The margin pressure may change as discharge pressure changes. Adjust margin pressure at Step 3 within operating conditions only.

   Note: Open adjustment for discharge flow (78) and adjustment for discharge pressure (81) on the 4C-3582 Load Sensing Valve before performing next steps of Test Procedure.

4. This step will verify pump efficiency.

   Increase the pump discharge pressure to the value in Step 4 of the test specifications. Compare the actual value of the case drain with the values in Step 4 of the test specifications. This value is an indication of the efficiency. If the case drain is more than the value in Step 4 of the test specifications, the pump may not be mechanically feasible. The pump should be internally inspected.

5. This step will verify pressure cutoff setting and minimum displacement of the pump.

   Increase the pump discharge pressure to the value in Step 5 of the test specifications. Turn the adjustment screw for pressure cutoff (51) or (52) until the actual pressure cutoff value is equal to the value in Step 5 of the test specifications. The discharge flow should be zero when the pressure cutoff is reached. If the discharge flow does not reach zero, turn the adjustment screw for minimum displacement (49) or (54) until discharge flow is within specification.

Repeat Steps 1 through 5 for the other 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 RPM and all pressures to zero. Remove the component from the test bench. Drain the oil from the pump. Plug all the ports.

Test Specifications

Tooling