Bench Test Procedure for Hydraulic Piston Pumps{5070} Caterpillar

Wheel Loader:

994F (S/N: 4421-UP)

Introduction

© 2014 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 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. In order 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

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, type of control, and internal components of the pump. 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 2	g01178572
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	g01178573
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	g01178574
Connections for the test bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil supply

Illustration 5	g01178575
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	g01178576
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) Control for the auxiliary oil supply (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

Illustration 7	g03419215
Port locations (49) Adjustment screw for minimum displacement on front pump (50) Adjustment screw for high-pressure cut (51) Adjustment screw for minimum displacement on rear pump (52) Pressure port for load sensing (53) Case drain port on rear pump (54) Suction port (55) Adjustment screw for margin pressure (56) Case drain port on front pump (57) Gauge port for charge pressure on rear pump (58) Case drain port on rear pump (59) Discharge port on rear pump (60) Discharge port on front pump (61) Case drain port on front pump (62) Gauge port for charge pressure on front pump (63) Case drain port on front pump (64) Adjustment screw for maximum displacement on front pump (65) Gauge port for discharge pressure on front pump (66) Gauge port for actuator pressure on front pump (67) Gauge port for actuator pressure on rear pump (68) Gauge port for discharge pressure on rear pump (69) Adjustment screw for maximum displacement on rear pump (70) Case drain port on rear pump

Illustration 8	g03419255
Hydraulic schematic (50) Adjustment screw for high-pressure cut (52) Pressure port for load sensing (53) Case drain port on rear pump (54) Suction port (55) Adjustment screw for margin pressure (56) Case drain port on front pump (57) Gauge port for charge pressure on rear pump (58) Case drain port on rear pump (59) Discharge port on rear pump (60) Discharge port on front pump (61) Case drain port on front pump (62) Gauge port for charge pressure on front pump (63) Case drain port on front pump (65) Gauge port for discharge pressure on front pump (66) Gauge port for actuator pressure on front pump (67) Gauge port for actuator pressure on rear pump (68) Gauge port for discharge pressure on rear pump (70) Case drain port on rear pump

Remote Control Pressure Relief Valve

Illustration 9	g03419257
(71) 8T-0859 Pressure Gauge (72) 8F-0024 Hose Assembly (73) 5P-3501 Adapter (74) 5P-6944 Straight Thread Adapter (75) 120-9181 Valve Body (76) 231-1286 Pressure Relief Valve (77) 2D-7325 Pipe Tee

Pump Setup

1. Mount the pump with case drain ports (58) and (61) facing upward.

2. Connect suction port (54) to the oil supply on the test bench using the adapter described in the Fabricated Tooling section of this document.

3. Connect a 1 inch high-pressure "XT6" hose from pump discharge port on rear pump (59) to a flow meter inlet on the test bench.

4. Connect a 1 inch high-pressure "XT6" hose from the flow meter outlet on the test bench back to the tank.

5. Connect a 1 inch high-pressure "XT6" hose from pump discharge port on front pump (60) to a flow meter inlet on the test bench.

6. Connect a 1 inch high-pressure "XT6" hose from the flow meter outlet on the test bench back to the tank.

7. Connect the pressure relief valve (76) to the valve body (75). Connect the valve body (75) to the straight thread adapter (74). Connect the straight thread adapter (74) to the adapter (73). Connect the adapter (73) to the pipe tee (77). Connect a pressure gauge (71) to the pipe tee (77). Connect a hose assembly (72) to the pipe tee (77). Do not connect the pressure relief valve assembly to the pump until specified.

8. Purge all air from the suction line. Loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction hose.

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

10. Connect a hose from the case drain port on rear pump (58) to an in-line flow meter. Direct oil from the in-line flow meter back to tank.

11. Connect a hose from the case drain port on front pump (61) to an in-line flow meter. Direct oil from the in-line flow meter back to tank.

12. Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump or 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 this procedure correlate with the steps in the test specification tables according to your specific part number.

The hydraulic oil in the test bench should meet and 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 ate 46° C (115° F)

In this procedure the front pump will be tested first in Steps 1 through 3 and the rear pump will be tested second in Steps 4 through 7.

1. Start rotating the pump according to the RPM 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 to raise the temperature of the oil and purge the system of air.

2. Slowly adjust the input RPM to the value in Step 2 of the Test Specifications. If the discharge flow from the front pump is different from the value in Step 2 of the Test Specifications, turn adjustment screw for minimum displacement on front pump (49) and adjustment screw for maximum displacement on front pump (64) accordingly until the flow is within specification.

3. Increase front pump discharge pressure to the value in Step 3 of the Test Specifications. Compare the actual values from the front pump case drain with the values in Step 3 of the Test Specifications. This value is an indication of the efficiency. If the case drain from the front pump is more than the value given in Step 3 of the Test Specifications, the pump may not be mechanically feasible. The pump should be internally inspected.

   Reduce RPM and all pressure to zero after the front pump has been tested.

4. Slowly adjust the input RPM to the value in Step 4 of the Test Specifications. If the discharge flow from the rear pump is different from the value in Step 4 of the Test Specifications, turn adjustment screw for maximum displacement on rear pump (69) accordingly until the flow is within specification.

5. Connect the Hose Assembly (72) to the pressure port for load sensing (52) on the pump. Connect the pressure relief valve (76) back to the tank.

   Rotate the pump according to the value in Step 5 of the Test Specifications. Turn the pressure relief valve (76) set screw clockwise until it is all the way in. Load the pump to the value in Step 5 of the Test Specifications. Turn the Pressure Relief Valve set screw counterclockwise until the discharge flow from the rear pump begins to drop. Read the pressure gauge (71). Adjust the adjustment screw for margin pressure (55) until the pressure gauge (71) reads the value of the "Pressure Relief Valve Pressure" in Step 5 of the Test Specifications.

   Disconnect the hose assembly (72) from the pump and plug pressure port for load sensing (52)

6. Rotate the pump according to the value in Step 6 of the Test Specifications. Increase the rear pump discharge pressure to the value in Step 6 of the Test Specifications. Compare the actual values from the rear pump case drain with the values in Step 6 of the Test Specifications. This value is an indication of the efficiency. If the rear pump case drain is more than the value given in Step 6 of the Test Specifications, the pump may not be mechanically feasible. The pump should be internally inspected.

7. Increase the rear pump discharge pressure to the value in Step 7 of the Test Specifications. Turn the adjustment screw for the high-pressure cut (50) until the actual high-pressure cut value is equal to the value in Step 7 of the Test Specifications. The discharge flow of the rear pump should be near zero when the high-pressure cut is reached.

   Reduce RPM and all pressure to zero after the rear pump has been tested.

Test Specifications

Test Bench Tooling