Bench Test Procedure for Hydraulic Piston Pumps{5070} Caterpillar

Excavator:

307D (S/N: DSG1-UP)

308D (S/N: FYC1-UP; GBT1-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 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 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	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 2	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 3	g01063314
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 4	g01093468
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 5	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

Port Locations

Illustration 6	g01445472
Typical port locations and adjustments (49) Stage two adjustment screw for the torque control (50) Stage one adjustment sleeve for the torque control (51) Negative flow control pressure port (52) Adjustment screw for maximum displacement (53) Pilot pump discharge port (54) Negative flow control gauge port (55) Suction port (56) Case drain port (57) Air purge port (58) Discharge port (59) Discharge gauge port

Illustration 7	g01445464
Hydraulic Schematic (51) Negative flow control pressure port (53) Pilot pump discharge port (54) Negative flow control gauge port (55) Suction port (56) Case drain port (58) Discharge port (59) Discharge gauge port

Pump Setup

Illustration 8	g01453067
Hydraulic schematic

1. Install quick disconnect fittings in the following ports:
   • (51) Negative flow control pressure port

   • (54) Negative flow control gauge port

   • (57) Air purge port

   • (59) Discharge gauge port

2. Connect the discharge port (58) to the flow meter inlet on the test bench. Direct flow meter outlet to the sump.

3. Connect the pilot pump discharge port (53) to a 8T-0454 Flow meter . Direct a line from the 8T-0454 Flow meter to the sump.

4. Vent the negative flow control pressure port (51) to the atmosphere. Vent the air purge port (57) to the atmosphere.

5. Connect a 8T-0855 Pressure Gauge to negative flow control gauge port (54). Connect a 8T-0860 Pressure Gauge to discharge gauge port (59) .

6. Connect the suction port (55) to the test bench oil supply. Purge all air from the suction line. Loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction hose.

7. Fill the pump case with oil. Pour oil directly into case drain port (56) until the case is full. Direct a line from case drain port (56) to the sump. Plug the air purge port (57) .

8. 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.

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)

Illustration 9	g01449352
Torque control characteristics (Q) Discharge flow (P) Discharge pressure

Illustration 10	g01502251
Negative flow characteristics for steps 3.a through 3.c (Q) Discharge flow (R) Negative flow control pressure

1. Start rotating the pump according to Step 1 of the test specifications. Listen for abnormal noise. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around the control valve. Verify flow from the pump. Run the pump for at least 5 minutes in order to raise the temperature of the oil and purge the system of air.

2. Step 2 will verify maximum displacement and torque characteristics. Compare the flow rates at each step to the values in Step 2.a through 2.d in the test specifications. Refer to the illustration 9 for an example of the torque curve. refer to illustration 11 for proper connections.
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   Illustration 11	g01453271
   Hydraulic schematic for Step 2.a through 2.d in the test specifications

   1. Slowly increase the input rpm. Compare the flow rate with Step 2.a of the test specifications. Turn the adjustment screw for maximum displacement (52) counterclockwise in order to increase flow. Turn the adjustment screw for maximum displacement (52) clockwise in order to decrease flow.
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   Illustration 12	g01449597
   Adjustments of torque control (49) Stage two adjustment screw for the torque control (50) Stage one adjustment sleeve for the torque control

   2. Slowly increase the discharge pressure to the value in Step 2.b of the test specifications. Compare the flow rate with Step 2.b of the test specifications. Adjust the stage one adjustment sleeve for the torque control (50) if the flow rate is not within specifications. Loosen the locknut and turn the stage one adjustment sleeve for the torque control (50) counterclockwise in order to increase flow. Turn the stage one adjustment sleeve for the torque control (50) clockwise in order to decrease flow. Tighten the locknut.

   3. Slowly increase the discharge pressure to the value in Step 2.c of the test specifications. Compare the flow rate with Step 2.c of the test specifications. Adjust the stage one adjustment sleeve for the torque control (50) if the flow rate is not within specifications. Loosen the locknut and turn the stage one adjustment sleeve for the torque control (50) counterclockwise in order to increase flow. Turn the stage one adjustment sleeve for the torque control (50) clockwise in order to decrease flow. Tighten the locknut.

   4. Slowly increase the discharge pressure to the value in Step 2.d of the test specifications. Compare the flow rate with Step 2.d of the test specifications. Adjust the stage two adjustment screw for the torque control (49) if the flow rate is not within specifications. Loosen the small locknut and turn the stage two adjustment screw for the torque control (49) counterclockwise in order to increase flow. Turn the stage two adjustment screw for the torque control (49) clockwise in order to decrease flow. Tighten the locknut.

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Illustration 13	g01450368
Negative flow characteristics for steps 3.a through 3.c (Q) Discharge flow (R) Negative flow control pressure

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Illustration 14	g01453338
Hydraulic schematic for Step 3 through 3.c in the test specifications

3. The following steps will verify the negative flow control. Refer to Illustration 14 for proper connections. Compare the flow rates at each step to the values in Step 3 through 3.c in the test specifications. Refer to the Illustration 13 for an example of the negative flow control curve.

   1. Increase the discharge pressure to the value in Step 3.a of the test specifications. Load the pilot pump discharge port (53) according to Step 3.a of the test specifications. The pilot pump discharge pressure will be used for the negative flow control pressure. The shims for the negative flow control will need to be adjusted if the flow is not within specifications. Adjust the shims until the flow is correct.

   2. Increase the negative flow control pressure to the value in Step 3.b of the test specifications. The shims for the negative flow control will need to be adjusted if the flow is not within specifications. Adjust the shims until the flow is correct.

   3. Increase the negative flow control pressure to the value in Step 3.c of the test specifications. The shims for the negative flow control will need to be adjusted if the flow is not within specifications. Adjust the shims until the flow is correct.

4. Step 4 measures the amount of internal leakage. Vent negative flow control pressure port (51) to atmosphere. Start rotating the pump according to Step 4 of the testing specifications. Increase the discharge pressure to the value listed in Step 4 of the test specifications. Compare the actual value from the case drain with the value in Step 4 of the testing specifications. This value is an indication of the pump efficiency. If the case drain is more than the value given in Step 4 of the test specifications, the pump may not be mechanically feasible. Internally inspect the pump.

Test Specifications

Test Bench Tooling