Bench Test Procedure for Hydraulic Piston Pumps {5070} Caterpillar

Pipelayer

PL72 (S/N: P721-UP; P731-UP)

PL83 (S/N: CB21-UP; DLW1-UP)

PL87 (S/N: TEC1-UP; ZAC1-UP)

Introduction

© 2017 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 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, use the following to relay your request to Caterpillar Repair Process Engineering:

• Cat dealer Technical Communicator

• Dealer Solution Network

• Caterpillar Technical Representative

• Knowledge Network (online)

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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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) 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" outlet for the flow meter with flow limiter (6) Oil supply (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 pump pressure (37) Signal pressure (38) Control for signal pressure (39) "Flow meter 1" discharge pressure (40) Control for auxiliary pump pressure (41) "Flow meter 2" discharge pressure (42) Auxiliary pump flow 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	g03862865
Port locations and adjustments (49) Gauge port for stroking pressure (50) Air purge port (51) Gauge port for stroking pressure (52) Electrical connector for pressure control solenoid (53) Charge filter port (to filter) (54) Charge filter port (from filter) (55) Adjustment screw for crossover relief valve (56) Electrical connector for switching solenoid (57) Gauge port for discharge pressure (58) Gauge port for charge pressure (59) Adjustment screw for charge relief valve (60) Adjustment screw for crossover relief valve (61) Gauge port for discharge pressure (62) Case drain port (63) Gauge port for control pressure (64) Adjustment screw for mechanical zero (65) Discharge port (66) Adjustment screw for pressure cutoff (67) Case drain port (68) Gauge port for high pressure (69) Discharge port (70) Suction port

Illustration 8	g03862866
Hydraulic schematic (49) Gauge port for stroking pressure (50) Air purge port (51) Gauge port for stroking pressure (52) Electrical connector for pressure control solenoid (53) Charge filter port (to filter) (54) Charge filter port (from filter) (55) Adjustment screw for crossover relief valve (56) Electrical connector for switching solenoid (57) Gauge port for discharge pressure (58) Gauge port for charge pressure (59) Adjustment screw for charge relief valve (60) Adjustment screw for crossover relief valve (61) Gauge port for discharge pressure (62) Case drain port (63) Gauge port for control pressure (64) Adjustment screw for mechanical zero (65) Discharge port (66) Adjustment screw for pressure cutoff (67) Case drain port (68) Gauge port for high pressure (69) Discharge port (70) Suction port

9U-5902 Rectifier Block

Illustration 9	g01359475
9U-5902 Rectifier Block Connections

Illustration 10	g01359478
9U-5902 Rectifier Block Schematic (71) high-pressure port (72) Outlet (73) low-pressure return (74) high-pressure port

9U-5893 Heat Exchanger

Illustration 11	g01360709
9U-5893 Heat Exchanger Connections (75) Inlet (76) Outlet (77) Water inlet (78) Water outlet

Pump Setup

Note: A power supply is required to operate the solenoids on this style of pump. The power supply should be capable of delivering 2 separate signals with an infinite range of 0 to 1300 mA and up to 24 V.

1. Install a pressure tap in the gauge port for charge pressure (58). Connect a properly rated pressure gauge to this port.

2. Connect a 1 inch high-pressure XT-6 hose from an auxiliary oil supply on the test bench to suction port (70).

3. Connect a 1 inch high-pressure XT-6 hose from filter port (53) to filter port (54).

4. Connect 1 inch high-pressure XT-6 hoses from the pump discharge ports (65) and (69) to the high-pressure ports (71) and (73) on the 9U-5902 Rectifier Block.

5. Connect a 1 inch high-pressure XT-6 hose from the outlet (72) of the 9U-5902 Rectifier Block to a flow meter inlet on the test bench.

6. Connect a hose from the flow meter outlet on the test bench to the heat exchanger inlet (75).

7. Connect a hose from the heat exchanger outlet (76) to the low-pressure return (74) on the 9U-5902 Rectifier Block.

8. Connect a water supply line to the coolant input (77) of the 9U-5398 Heat Exchanger. Connect a water drain line to the coolant output (78) of the 9U-5398 Heat Exchanger.

9. Vent air purge port (50) to atmosphere. Fill the pump case with oil. Pour oil directly into case drain port (67). Plug air purge port (50) when pump case is full. Direct flow from case drain port (67) back to the test bench reservoir.

10. Connect a power supply to the electrical connector for pressure control solenoid (52).

11. Connect a power supply to the electrical connector for switching solenoid (56).

12. 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.

Adjustment for Mechanical Zero Position

1. Install pressure taps in gauge ports for stroking pressure (49) and (51). Connect gauge ports for stroking pressure (49) and (51) together with a high-pressure hose. This will equalize the pressure on the servo spool. Install pressure gauges on gauge ports for discharge pressure (57) and (61). This unit is not equipped with a charge pump. Be sure to sustain auxiliary oil flow to suction port (70) in Steps 1 through step 5 of the Adjustment for Mechanical Zero Position according to the values given in Step 1 of the Test Specifications. Start rotating the pump according to the input speed in Step 1 of the Test Specifications. Turn the load control on the test bench completely clockwise in order to control the pump discharge pressure. If the mechanical zero adjustment is incorrect, a discharge pressure higher than the charge pressure may occur.

2. Turn the adjustment screw for the mechanical zero (64) clockwise. Continue to turn the adjustment screw until a pressure of 200 psi above charge pressure is achieved. This pressure may be seen on the gauge port for discharge pressure (57) or gauge port for discharge pressure (61). Mark the position of the adjustment screw for the mechanical zero (64).

3. Turn adjustment screw for the mechanical zero (64) counterclockwise until pressure increases to 200 psi about charge pressure on gauge port for discharge pressure (57) or (61). Mark the position of the adjustment screw for the mechanical zero (64).

4. A mark should be placed halfway between position one and position two. Turn the adjustment screw for the mechanical zero (64) to the midpoint of both marks. There should be less than a 34.5 kPa (5 psi) pressure differential between gauge ports for discharge pressure (57) and (61).

5. Stop rotating the pump. Turn the load control on the test bench for pump discharge pressure counterclockwise. Decrease auxiliary oil flow to suction port (70). Allow the discharge pressure of the pump to decrease. Disconnect pressure gauges from gauge ports for discharge pressure (57) and (61). Plug gauge ports for stroking pressure (49) and (51).

Test Procedure

Note: The steps in the Test Procedure correlate with the steps in 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)

• Mobil DTE-11 at 46° C (115° F)

1. This step will verify pump connections and proper flow.

   Increase auxiliary charge flow and auxiliary charge pressure to the values in Step 1 of the Test Specifications. Start rotating the pump according to the input speed in Step 1 of the Test Specifications.

   Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around control valves. Run the pump for at least five minutes in order to raise the temperature of the oil and purge the system of air. Verify flow rates.

2. This step will verify maximum displacement of the pump

   Slowly increase the pump input speed to the value in Step 2 of the Test Specifications. Increase discharge pressure to the value in Step 2 of the Test Specifications. Verify the discharge flow with the value in Step 2 of the Test Specifications. If the flow is not within specification, the pump may not be mechanically feasible. The pump should be internally inspected.

3. This step will verify pump volumetric efficiency. Increase pump discharge pressure to the value in Step 3 of the Test Specification. Measure pump discharge flow. Calculate the total pump loss.

   Subtract the discharge flow that was recorded in Step 3 from the discharge flow that was recorded in Step 2 of the Test Procedure to find the total loss.

   Example: "Step 2 flow" 162 lpm (42.8 gpm) - "Step 3 flow" 158 lpm (41.7 gpm) = "total loss" 4 lpm (1.1 gpm). The "max. allowable loss" is 7.2 lpm (1.9 gpm).

   The pump in the example is acceptable because the actual total loss is less than the maximum allowable loss.

4. This step will verify the setting of the crossover relief valves.

   Note: This step should only be performed if the fittings, hoses, and test bench are rated for the pressures given in Step 4 of the Test Specifications. Skip to Step 5 if your fittings, hoses, or test bench are not rated for the pressures in Step 4 of the Test Specifications.

   Turn the adjustment screw for pressure cutoff (66) completely clockwise. Slowly increase discharge pressure to the value in Step 4 of the Test Specifications. Verify that the pump cannot build pressure greater than the value in Step 4 of the Test Specifications. If the discharge pressure is not within specification, adjust the adjustment screw for crossover relief valve (55) or (60) depending on which side of the pump is being tested. If the crossover relief valve is not adjustable, it may need to be replaced.

5. This step will verify the setting of the pressure cutoff valve.

   Decrease the discharge pressure to the value given in Step 5 of the Test Specifications. The pump should destroke and the flow should decrease to the value in Step 5 of the Test Specifications. If the pump does not destroke, turn the adjustment screw for pressure cutoff (66) until the pump destrokes at the pressure in Step 5 of the Test Specifications.

6. This step will verify the proper function of the pressure control solenoid.

   Decrease discharge pressure to the value in Step 6 of the Test Specifications. Increase current to the electrical connector for pressure control solenoid (52) to the value given in Step 6 of the Test Specifications. Verify that pump discharge flow decreases to the value given in Step 6 of the Test Specifications. It is acceptable for pump discharge pressure to decrease during this step.

Reduce all currents, pressures, flows, and input speed to zero. Increase current to electrical connector for switching solenoid (56) to 700 mA and repeat Steps 1 through 6 to test the other side of the pump.

Reduce all pressures, flows, and input speed to zero. Remove component from the test bench. Drain the oil from the pump. Securely cap or plug all ports.

Test Specifications

Bench Test Tooling