Bench Test Procedure for Hydraulic Piston Pumps{5070} Caterpillar

Excavator:

375 (S/N: 8WJ1-UP; 6NK1-UP)

375L (S/N: 9WL1-UP; 1JM1-UP)

5080 (S/N: 6XK1-UP; 8SL1-UP)

5130 (S/N: 5ZL73-105,106-UP)

5130B (S/N: 4CS1-UP)

5230 (S/N: 7LL1-43,44-65,66-UP)

Off-Highway Truck/Tractor:

773E (S/N: ASK1-UP)

Introduction

© 2012 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.

This Special Instruction provides pump test procedures and specifications for testing a hydraulic pump on a test bench. The technician should have a good understanding of hydraulic piston pumps. The technician should fully understand how to correctly and safely operate the specific test bench used. The test benches shown and utilized in this procedure are offered by the Caterpillar Service Tool Division. The test benches shown may not hook up the same as the bench available at the dealership. Required tooling to connect the pump should be gathered before the pump is tested. 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 for in the Service Information System website. In order to address an urgent need, 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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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 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) in order to view the latest version.

References

Connections for the Caterpillar Hydraulic Test Center

Illustration 1	g01039044
Connections for the Test Center (1) Discharge flow control (2) F3 flow meter inlet (3) F3 flow meter outlet (4) Return to tank (5) Case drain connections (6) Load sense pressure port (7) Oil supply

Illustration 2	g01039045
Controls and Gauges for the Test Center (8) F3 discharge pressure gauge (9) F3 flow meter readout (10) Margin pressure gauge (11) F3 pump discharge pressure load control

Connections for the Caterpillar Hydraulic Test Bench

Illustration 3	g01039046
Connections for the Test Bench (12) Flow meter loop connections (13) Oil Supply

Illustration 4	g01039047
Connections for the Test Bench (14) Flow meter loop 2 (15) Flow meter loop 2 outlet (16) Flow meter loop 2 inlet

Illustration 5	g01039048
Test Bench Controls and Gauges (17) Speed control (18) Pump discharge pressure gauge 2 (19) Flow meter 2 (20) Pump discharge pressure load control 2

4C-3582 Load Sensing Valve

Illustration 6	g01040454
4C-3582 Load Sensing Valve

Illustration 7	g01040456
Schematic for 4C-3582 Load Sensing Valve (21) Outlet port (22) Adjustment knob for discharge flow (23) High-pressure port (24) Inlet port (25) Adjustment knob for discharge pressure (26) Low-pressure port (27) Pressure port for load sensing

Illustration 8	g01039049
4C-3582 Load Sensing Valve and 1U-5796 Pressure Differential Gauge (21) To the flow meter on the test bench (22) Adjustment knob for discharge flow (23) To the high side of the differential gauge (24) From the pump discharge port (25) Load control for pump discharge pressure (26) To the low side of the differential gauge (27) Pressure port for load sensing (28) To the low side of the load sensing valve (29) Pressure differential gauge group (30) To high side of the load sensing valve

Port Locations

Illustration 9	g00993563
Typical port locations and adjustments (31) Case drain port (32) Adjustment screw for power shift (33) Pressure port for load sensing (34) Suction port (35) Adjustment screw for margin pressure (36) Pressure port for power shift (37) Adjustment screw for minimum angle (38) Case drain port (39) Adjustment screw for maximum angle (40) Discharge port

Pump Pre-Test Set Up

1. Connect a hose from the test bench oil supply to suction port (34) on the pump.

2. Connect a hose from pressure port (40) to the flowmeter inlet on the test bench.

3. Connect a 177-7860 Hose Assembly from port (33) to a discharge pressure port.

4. Connect a 177-7860 Hose Assembly from an auxiliary pressure source to port (36) .

5. Purge all air from the suction line before rotating the pump. Loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction fitting.

6. Fill the pump case with oil before rotating. Pour oil directly into a case drain port until the case is full.

7. Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump. The direction of rotation is viewed from the input shaft end. Visually check for proper test bench rotation.

Test Procedure

Note: The steps in this procedure will coordinate with the steps in Table 3 according to your specific part number.

Note: The oil used to test the pump should be either:

• SAE 10W at 60° C (140° F) or

• Mobil DTE-11 at 46° C (115° F)

Illustration 10	g01046362

1. Apply power shift pressure to port (36) according to the value given in Step 1. Start rotating the pump according to Step 1 of the test specifications. Listen for abnormal noise. Verify that all the connections are not leaking. Check for leaks around shaft seals and control valves.

2. Increase the input RPM according to Step 2 of the test specifications. Check flow. If the pump discharge flow rates are not within specifications, adjustment is necessary. To decrease flow, loosen the locknut. Turn the adjustment screw for maximum angle (39) clockwise. To increase flow, turn the adjustment screw for maximum angle (39) counterclockwise.

3. Use the following steps to set the margin pressure of both pumps.

   Note: The 4C-3582 Load Sensing Valve will be installed for Step 3 only. The load sensing valve will not flow enough to conduct the remainder of the test.

   1. Stop rotating the pump. Turn off the test bench.

   2. Install the 4C-3582 Load Sensing Valve in the test circuit. Refer to Illustration 6 through Illustration 8 for proper installation of the load sensing valve.

   3. The pump discharge flow is adjusted by using the 4C-3582 Load Sensing Valve . Bench circuitry will be used for adjusting pump discharge flow when testing with a Caterpillar Test Center. Adjust the discharge flow and discharge pressure according to the values given in Step 3 of the test specs. Adjust the margin pressure set screw (35) to the value given in Step 3 of the test specs. The margin pressure will be displayed on the 1U-5796 Pressure Differential Gauge .

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

   4. After the margin pressure is set, turn out the control for discharge flow all the way. Turn out the load control for pump discharge pressure all the way. Stop rotating the pump. Turn off the test bench. Remove the 4C-3582 Load Sensing Valve from the circuit. Connect a 177-7860 Hose Assembly from port (33) to a discharge pressure port.

4. Apply power shift pressure to port (36) according to the value given in Step 4. Start rotating the pump according to Step 4 of the test specifications. Load the pump discharge pressure to the value in Step 4 of the test specifications. Observe case drain flow. Case drain should not be more than the value given in 4 of the test specifications. The pump flow rate may drop off due to the horsepower control, which is not a concern in this step.

5. Reduce pump discharge pressure to zero. Apply power shift pressure to port (36) according to the value given in Step 5. Rotate the pump according to Step 5 of the test specifications. Increase the discharge pressure to the value given in Step 5. As discharge pressure increases, the pump should destroke and flow will drop. The discharge flow should be at the value given in Step 5 of the test specifications. If the flow rate is too low or too high, the adjustment screw for power shift (32) must be adjusted. If the pump will not reach the flow value given, turn the adjustment screw for power shift clockwise. If the pump reaches a flow rate higher than the value given, turn the adjustment screw for power shift counterclockwise.

6. Reduce pump discharge pressure to zero. Apply power shift pressure to port (36) according to the value given in Step 6. Rotate the pump according to Step 6 of the test specifications. Increase the discharge pressure to the value given in Step 6 of the test specifications. As discharge pressure increases, the pump should destroke and flow will drop. The discharge flow should be at the value given in Step 6 of the test specifications. If the flow rate is too low or too high, the adjustment screw for power shift (32) must be adjusted. If the pump will not reach the flow value given, turn the adjustment screw for power shift clockwise. If the pump reaches a flow rate higher than the value given, turn the adjustment screw for power shift clockwise.