Bench Test Procedure for Hydraulic Piston Pumps {5070} Caterpillar

Off-Highway Truck/Tractor

793F (S/N: SND1-UP; SSP1-UP; D3T1-UP; RBT1-UP)

793F AC (S/N: EMD1-UP)

Introduction

© 2017 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 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 technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.

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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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.

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

Connections for the Caterpillar Hydraulic Test Center

Illustration 2	g00946786
Connections for the Test Center (11) Flow control for discharge (12) "F3" flow meter inlet (13) "F3" flow meter outlet (14) Return to tank (15) Connections for case drain (16) "F4" flow meter inlet (17) "F4" flow meter outlet (18) Return to tank (19) Oil supply

Illustration 3	g00946789
Control and Gauges for the Test Center (20) "F3" discharge pressure gauge (21) "F3" discharge flow (22) "F4" discharge pressure gauge (23) "F4" discharge flow (24) "F3" Load control for discharge pressure (25) "F4" Load control for discharge pressure

Connections for the Caterpillar Hydraulic Test Bench

Illustration 4	g00946790
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 5	g00946791
Connections for the Test Bench (28) "Flow meter 2" loop (29) "Flow meter 1" loop (30) "Flow meter 2" outlet (31) "Flow meter 2" inlet (32) "Flow meter 1" outlet (33) "Flow meter 1" inlet

Illustration 6	g00946792
Control and Gauges for the Test Bench (34) "Flow meter 1" discharge pressure (35) "Flow meter 1" discharge flow (36) "Flow meter 1" load control (37) Speed and direction control (38) "Flow meter 2" discharge pressure (39) "Flow meter 2" discharge flow (40) "Flow meter 2" load control

Port Locations

Illustration 7	g02035082
Typical port locations, adjustments, and hydraulic schematic. (41) Minimum angle stop screw "front pump" (42) "T1" Air purge (43) Displacement solenoid "rear pump" (44) High-pressure cutoff adjustment "rear pump" (45) Current Adjustment Screw "rear pump" (46) Minimum angle stop screw "rear pump" (47) Maximum angle stop screw "rear pump" (48) "T2A" Air purge (49) "S" Suction port (50) Maximum angle stop screw "front pump" (51) "L1" Seal cavity vent (52) Steering pump discharge pressure adjustment "front pump" (53) "U" Bearing flushing (54) "T2" Air purge (55) "B" Discharge port "front pump" (56) "G1" Control pressure "front pump" (57) "G2" Control pressure "rear pump" (58) "A" Discharge port "rear pump" (59) "T1A" Air purge (60) "U" Bearing flushing (61) "MB" Gauge port for system pressure "front pump" (62) "M1A" Gauge port for destroking pressure "rear pump" (63) "SL" Suction pressure after charge pump "front pump" (64) "M1B" Gauge port destroking pressure "front pump" (65) "MA" Gauge port for system pressure "rear pump" (66) "R2" Case drain (67) Gauge port for system pressure "rear pump" (68) Gauge port for system pressure "front pump" (69) "R1" Case drain (70) "L1" Seal cavity vent

Schematic

Illustration 8	g02035353

Set up for the Front Pump

Note: A power supply will be required to operate the solenoid on the rear pump. The power supply can deliver 0 mA to 600 mA.

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Illustration 9	g02046458

1. Remove tube (71) that connects "MB" (61) to "G2" (57). Plug "MB" (61) and "G2" (57).

2. Connect one end of a high-pressure "XT6" hose to the discharge port "front pump" (55). Connect the other end of the high-pressure "XT6" hose to the flow meter inlet on the test bench.

3. Connect one end of a high-pressure "XT6" hose to the flow meter outlet on the test bench. Connect the other end of the high-pressure "XT6" hose to the tank.

4. Connect the oil supply suction hose to pump inlet port (49).

5. Connect one end of a high-pressure "XT6" hose to the discharge port "rear pump" (58). Connect the other end of the high-pressure "XT6" hose to the tank.

6. 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 hose.

7. Fill the pump case with oil before rotating. Pour oil directly into a case drain port (66) or (69) until the case is full.

8. Connect an in-line flow meter to a case drain port (66) or (69). Direct the oil from the in-line flow meter back to the tank.

9. 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 the rotation of the pump being tested for proper direction of rotation.

   Note: Each pump will be tested independently.

Test Procedure for the Front Pump

Note: The steps in the 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 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 10	g01378800

Note: Always remove all pump discharge pressure before decreasing the solenoid current to zero. If not discharged, the discharge pressure will increase rapidly.

1. Start rotating the pump according to the input speed in Step 1 of the Test Specifications. Apply 600 mA of current to control the solenoid on the rear pump that will not be tested at this time. Slowly increase discharge pressure of the rear pump until flow is at zero. Listen for abnormal noise. Verify the flow from the pump that is being tested. 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 increase the input RPM 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, adjust the screw for the maximum angle (50). Turn the adjustment screw for maximum angle (50) clockwise to decrease flow. Turn the adjustment screw for maximum angle (50) counterclockwise to increase flow.

3. Increase the pump discharge pressure to the value in Step 3 of the Test Specifications. Compare the actual case drain value with the case drain value in Step 3 of the Test Specifications. This value is an indication of the pump efficiency. The pump may not be mechanically feasible if the case drain is more than the value in Step 3 of the Test Specifications. The pump should be disassembled and inspected.

4. Increase the pump discharge pressure to the value in Step 4 of the Test Specifications. Turn the adjustment screw for the high-pressure cut (52) until the actual high-pressure cut value is equal to the value in Step 4 of the Test Specifications. Turn the adjustment screw for the high-pressure cut (52) clockwise to increase the high-pressure cut. Turn the adjustment for the high-pressure cut (52) counterclockwise to decrease the high-pressure cut. Pump discharge flow should be zero when the high-pressure cut is reached.

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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, amperage, and RPM to zero.

Set up for the Rear Pump

Note: A power supply will be required to operate the solenoid on the rear pump. The power supply can deliver 0 mA to 600 mA. The testing points will be 0 mA, 200 mA, 400 mA, and 600 mA.

1. Connect one end of a high-pressure "XT6" hose to the discharge port "rear pump" (58). Connect the other end of the high-pressure "XT6" hose to the flow meter inlet on the test bench.

2. Connect one end of a high-pressure "XT6" hose to the flow meter outlet on the test bench. Connect the other end of the high-pressure "XT6" to the tank.

3. Connect one end of a high-pressure "XT6" hose to the discharge port "front pump" (55). Connect the other end of the high-pressure "XT6" to the tank.

4. Vent "G2" (57) to atmosphere. Direct hose to tank to prevent oil spill.

5. Plug "MB" (61). "MB" (61) should still be plugged from testing the front pump.

6. Connect signal pressure line to "M1B" (64) to destroke front pump which is not being tested.

7. 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 hose.

8. Fill the pump case with oil before rotating. Pour oil directly into a case drain port (66) or (69) until the case is full.

9. Connect a hose from the case drain port (66) or (69) to an in-line flow meter. Direct the oil from the in-line flow meter to the tank.

10. 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 the rotation of the test bench for proper direction.

Test Procedure for the Rear Pump

Note: The steps in the 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 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 11	g00946725

Note: Always remove all pump discharge pressure before decreasing the solenoid current to zero. If not discharged, the discharge pressure will increase rapidly.

1. Start rotating the pump according to the input speed in Step 1 of the Test Specifications. Apply 21 bar (305 psi) to "M1B" (64) to destroke front pump which is not being tested at this time. Slowly increase discharge pressure until flow is at zero. Listen for abnormal noise. Verify the flow from the pump that is being tested. 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 increase the input RPM 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, adjust the screw for the maximum angle (47). Turn the adjustment screw for maximum angle (47) clockwise to decrease flow. Turn the adjustment screw for maximum angle (47) counterclockwise to increase flow.

3. Slowly increase the pump discharge pressure to the value in Step 3 of the Test Specifications. Note the discharge flow.

4. Apply the current value in Step 4 of the Test Specifications to the rear pump. If necessary, adjust the discharge pressure to the value in Step 4 of the Test Specifications. The discharge flow should equal the value in Step 4 of the Test Specifications. If the discharge flow is too low, turn the adjustment screw for solenoid (45) clockwise. If the discharge flow is too high, turn the adjustment screw for solenoid (45) counterclockwise. No further adjustment of the adjustment screw for solenoid (45) is necessary.

5. Increase the current to the value in Step 5 of the Test Specifications. Discharge flow should go down to the value in Step 5 of the Test Specifications.

6. Increase the current value to the value in Step 6 of the Test Specifications. Discharge flow should go down to the value in Step 6 of the Test Specifications. If the discharge flow does not equal the value in Step 6 of the Test Specifications, turn the adjustment screw for minimum swashplate angle (46) for the pump that is being tested. Turn adjustment screw for minimum swashplate angle (46) clockwise to increase the flow. Turn adjustment screw for the minimum swashplate angle counterclockwise to decrease flow.

7. Remove all discharge pressure from the pump that is being tested. Then, lower the current to zero. Do not lower the current first. The pump discharge pressure will immediately go to the high-pressure cut value. Increase the pump discharge pressure to the values in Step 7 of the Test Specifications. Compare the actual values for the case drain with the values in Step 7 of the Test Specifications. This value is an indication of the efficiency. If the case drain is more than the value given in Step 7 of the Test Specifications, the pump may not be mechanically feasible. The pump is to be internally inspected.

8. Slowly adjust the input RPM to the value in Step Test Specifications. Increase the pump discharge pressure to the value in Step 8 of the Test Specifications. Turn the adjustment screw for the high-pressure cut (44) until the actual high-pressure cut value is equal to the value in Step 8 of the Test Specifications. Turn the adjustment screw for the high-pressure cut (44) clockwise to increase the high-pressure cut. Turn the adjustment for the high-pressure cut (44) counterclockwise to decrease the high-pressure cut. The discharge flow should be zero when the high-pressure cut is reached.

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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 of the ports and reinstall tube (71) shown in Illustration 9.

Test Specifications

Test Bench Tooling