Bench Test Procedure for Hydraulic Piston Pumps {0738, 5070} Caterpillar

Excavator

374F (S/N: AT21-UP; AP41-UP; NFJ1-UP; MFL1-UP; DNM1-UP)

390F (S/N: HJD1-UP; TYE1-UP; MGF1-UP; HSM1-UP; GAY1-UP)

Material Handler

MH3295 (S/N: PA91-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 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 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. To address an urgent need, use the following to relay your request to Caterpillar Repair Process Engineering:

• Cat Dealer Technical Communicator

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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 and the type of control. The test procedure should be used with the test specifications and tooling sections. Both sections are displayed toward the back of this document.

Note: This Bench Test Procedure has been validated for test benches capable of delivering 300 kW (400 hp) of power of greater. Using this Bench Test Procedure with test benches incapable of achieving this power range may be unsuccessful.

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

Connect for the Caterpillar Hydraulic Test Center

Illustration 2	g01581273
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	g01581274
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	g01581278
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 5	g01581279
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	g01581280
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

Pump Illustrations

Illustration 7	g03572237
Port locations (49a) Flow control pressure port for front pump (49b) Flow control pressure port for rear pump (50a) Swashplate position sensor for front pump (50b) Swashplate position sensor for rear pump (51a) Control pressure port for front pump (51b) Control pressure port for rear pump (52a) Adjustment screw for powershift pressure spring for front pump (52b) Adjustment screw for powershift pressure spring for front pump (53a) Powershift pressure port for front pump (53b) Powershift pressure port for rear pump (54a) Cross sensing pressure port for front pump (pilot pressure from rear pump) (54b) Cross sensing pressure port for rear pump (pilot pressure from front pump) (55a) Adjustment screw for cross sensing for front pump (55b) Adjustment screw for cross sensing for rear pump (56) Case drain port (57a) Adjustment screw for minimum displacement for front pump (57b) Adjustment screw for minimum displacement for rear pump (58) Suction port (59a) Case drain port for front pump (59b) Case drain port for rear pump (60a) Adjustment screw for maximum displacement for front pump (60b) Adjustment screw for maximum displacement for rear pump (61a) Gauge port for control pressure for front pump (61b) Gauge port for control pressure for rear pump (62a) Gauge port for discharge pressure for front pump (62b) Gauge port for discharge pressure for rear pump (63a) Discharge port for front pump (63b) Discharge port for rear pump

Illustration 8	g03669846
Pressure port and adjustment locations on controller (49) Flow control pressure port (52) Adjustment screw for powershift pressure spring (53) Powershift pressure port (54) Cross sensing pressure port (55) Adjustment screw for cross sensing (64) Adjustment screw for flow control pressure spring

Illustration 9	g03572238
Hydraulic schematic (49a) Flow control pressure port for front pump (49b) Flow control pressure port for rear pump (51a) Control pressure port for front pump (51b) Control pressure port for rear pump (52a) Adjustment screw for powershift pressure spring for front pump (52b) Adjustment screw for powershift pressure spring for front pump (53a) Powershift pressure port for front pump (53b) Powershift pressure port for rear pump (54a) Cross sensing pressure port for front pump (pilot pressure from rear pump) (54b) Cross sensing pressure port for rear pump (pilot pressure from front pump) (55a) Adjustment screw for cross sensing for front pump (55b) Adjustment screw for cross sensing for rear pump (56) Case drain port (57a) Adjustment screw for minimum displacement for front pump (57b) Adjustment screw for minimum displacement for rear pump (58) Suction port (59a) Case drain port for front pump (59b) Case drain port for rear pump (60a) Adjustment screw for maximum displacement for front pump (60b) Adjustment screw for maximum displacement for rear pump (61a) Gauge port for control pressure for front pump (61b) Gauge port for control pressure for rear pump (62a) Gauge port for discharge pressure for front pump (62b) Gauge port for discharge pressure for rear pump (63a) Discharge port for front pump (63b) Discharge port for rear pump (64a) Adjustment screw for flow control pressure spring for front pump (64b) Adjustment screw for flow control pressure spring for rear pump (65a) Cross sensing line for front pump - not included on pump (65b) Cross sensing line for rear pump - not included on pump

Pump Setup

1. Mount the pump with suction port (58) downward. Connect suction port (58) to the test bench oil supply.

2. Connect 1 inch high pressure "XT6" hoses from the pump discharge ports (63a) and (63b) to separate flow meter inlets on the test bench. Connect 1 inch high pressure "XT6" hoses from the flow meter outlets to tank.

3. Install pressure taps in flow control pressure ports (49a) and (49b).

4. Install pressure taps in powershift pressure ports (53a) and (53b).

5. Install pressure taps in cross sensing pressure ports (54a) and (54b).

6. Install pressure taps in gauge ports for discharge pressure (62a) and (62b).

7. Connect flow control pressure ports (49a) and (49b) with a tee and vent to atmosphere. Reserve a signal pressure supply on the test bench capable of producing at least 3100 kPa (450 psi) to supply these ports later in the test procedure.

8. Connect powershift pressure ports (53a) and (53b) with a tee and vent to atmosphere. Reserve a signal pressure supply on the test bench capable of producing at least 2415 kPa (350 psi) to supply these ports later in the test procedure.

9. Connect gauge port for discharge pressure (62b) to cross sensing pressure port (54a) as shown by cross sensing line (65a) in Illustration 9. Connect gauge port for discharge pressure (62a) to cross sensing pressure port (54b) as shown by cross sensing line (65b) in Illustration 9. Later in the test procedure, these lines will need to be alternately connected to a signal pressure oil supply capable of producing at least 28000 kPa (4060 psi).

10. Fill pump case with oil. Pour oil directly into case drain ports (59a) and (59b) until the case is full.

11. Purge all air from the suction line. Carefully loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction hose.

12. Install flow meter to case drain port (59a). Route the discharge back to tank.

13. Connect a multimeter to the swashplate position sensors (50a) and (50b).

    Note: Refer to the "Swashplate Position Sensor Setup" section of this document.

14. 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.

Swashplate Position Sensor Setup

Illustration 10	g03612379
146-4080 Digital Multimeter Gp (66) Common port (67) Voltage port

Illustration 11	g03612380
276-7273 Sensor Test Box (Position Sensor) (68) Positive voltage banana connector (69) Negative voltage banana connector (70) Four-pin Deutsch connector (71) Battery test momentary switch

Illustration 12	g03669898
Fabricated electrical adapter (72) Four-pin Deutsch connector (73) Three-pin Deutsch connector

Illustration 13	g03612678
Schematic of swash plate position sensing setup (50a) Swashplate position sensor for front pump (50b) Swashplate position sensor for front pump (68) Positive voltage banana connector (69) Negative voltage banana connector (70) Four-pin Deutsch connector (71) Battery test momentary switch (72) Four-pin Deutsch connector (73) Three-pin Deutsch connector

1. Connect 276-7273 Sensor Test Box to 146-4080 Digital Multimeter Gp. Insert positive voltage banana connector (68) into voltage port (67) and negative voltage banana connector (69) into common port (66).

   Note: Use an electrical adapter to connect 276-7273 Sensor Test Box to the swashplate position sensor (50a) or (50b) on the pump. To fabricate this adapter, refer to Illustration 13 for the schematic.

2. Connect four-pin Deutsch connector (70) into four-pin Deutsch connector (72).

3. Connect three-pin Deutsch connector (73) to the swashplate position sensor (50a) or (50b). The swashplate position sensors will need to be tested one at a time.

4. Turn on 146-4080 Digital Multimeter Gp to read DC voltage. The battery power of the 276-7273 Sensor Test Box can be checked by holding in the battery test momentary switch (71) while the multimeter is on.

Test Procedure

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Illustration 14	g03671229

1. Verify that the pump controls are plumbed as shown in Illustration 14. Start rotating the pump according to Step 1 of the Test Specifications. Listen for abnormal noise. Verify that all connections are not leaking. Check for leaks around shaft seals and control valves.

   Run the pump for at least 5 minutes to raise the temperature of the oil and purge the system of air.

2. This step will verify the maximum displacements and the swashplate sensors of the front and rear pump.

   Slowly increase the input speed according to Step 2 of the Test Specifications. If the front or rear pump maximum flow is not within specifications, adjust the adjustment screw for maximum displacement (60a) or (60b). Loosen the locknut and turn the adjustment screw for maximum displacement (60a) or (60b) counterclockwise to increase the discharge flow until it is within specifications. Loosen the locknut and turn the adjustment screw for maximum displacement (60a) or (60b) clockwise to decrease the discharge flow until it is within specifications. Tighten the locknut after the discharge flows have been properly set.

   Verify correct voltage from front and rear swashplate position sensors (50a) and (50b) according to 2 of the Test Specifications.

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   Illustration 15	g03671244

3. This step will verify the minimum displacements and the swashplate sensors of the front and rear pumps. This step will also verify flow control functionality.

   Connect teed flow control pressure ports (49a) and (49b) to a pilot pressure supply as shown in Illustration 15. Apply flow control pressure to the flow control pressure ports (49a) and (49b) according to Step 3 of the Test Specifications. Increase the front and rear pump discharge pressures to the values in Step 3 of the Test Specifications.

   Verify discharge flows according to Step 3 of the Test Specifications to ensure that the flow control is functioning properly. If the front or rear pump discharge flow is not within specifications, adjust the adjustment screw for flow control pressure spring (64a) or (64b). Loosen the locknut and turn the adjustment screw for flow control pressure spring (64a) or (64b) until discharge flow is within specifications. Tighten the locknut after the flow control pressures have been properly set. If specified discharge flow is not reached from adjusting the flow control pressure spring, turn the adjustment screw for minimum displacement (57a) or (57b) counterclockwise to decrease the discharge flow to the specified value.

   Verify correct voltage from front and rear swashplate position sensors (50a) and (50b) according to Step 3 of the Test Specifications.

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   Illustration 16	g03669953
   Cutaway view of pump control (one pump). (A) Length dimension of adjustment screw for cross sensing (52) Adjustment screw for powershift pressure spring (53) Powershift pressure port (54) Cross sensing pressure port (55) Adjustment screw for cross sensing

4. This step is for manually setting the cross sense pressure. This is a coarse adjustment of the cross sense pressure. A finer adjustment of the cross sense pressure will be conducted in Steps 5.b and 6.b.

   Reduce all pressures and the input speed to zero for this step. Loosen the locknut and turn the adjustment screw for cross sensing (55a) and (55b) until it protrudes to the length (A) given in Step 4 of the"Test Specifications". This length is measured from the tip of the adjustment screw to the face of the control boss as show in Illustration 16. Tighten the locknut after the adjustment screw length has been properly set.

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   Illustration 17	g06241811

5. This step will check the torque control and cross sensing functionality of the front pump. This step will also check front pump efficiency.

   For this step, it is necessary to vent flow control pressure port for front pump (49a) to atmosphere. Connect flow control pressure port for rear pump (49b) to a pilot pressure supply. Connect a pilot pressure supply to a tee that connects power shift pressure ports (53a) and (53b). Connect a pilot pressure supply to cross sensing pressure port for front pump (54a). Cross sense pressure port for rear pump (54b) should still be connected to gauge port for discharge pressure for front pump (62a). Refer to Illustration 17 for correct plumbing.

   1. Increase input speed to the value in Step 5.a of the"Test Specifications". Increase pilot pressure to powershift pressure ports (53a) and (53b) according to Step 5.a of the"Test Specifications". Increase the pilot pressure to the cross sensing pressure port for the front pump (54a) according to Step 5.a of the"Test Specifications". Increase discharge pressure on the front pump according to Step 5.a of the"Test Specifications". Verify correct discharge flow from the front pump. If the discharge flow is not correct, turn the adjustment screw for powershift pressure spring for front pump (52a) until the discharge flow from the front pump is within specifications. Verify that the case drain is less than or equal to the value in Step 5.a of the"Test Specifications".

   2. Increase the pilot pressure to the cross sensing pressure port for the front pump (54a) according to Step 5.b of the"Test Specifications". Verify correct discharge flow from the front pump. If the discharge flow is not correct, turn the adjustment screw for cross sensing for front pump (55a) until the discharge flow from the front pump is within specifications. Tighten locknut after discharge flow has been properly set.

      Reduce all pressures and input speed to zero.

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   Illustration 18	g06241813

6. This step will check the torque control and cross sensing functionality of the rear pump. This step will also check rear pump efficiency.

   For this step, it is necessary to vent flow control pressure port for rear pump (49b) to atmosphere. Connect flow control pressure port for front pump (49a) to a pilot pressure supply. Connect a pilot pressure supply to a tee that connects power shift pressure ports (53a) and (53b). Connect a pilot pressure supply to cross sensing pressure port for rear pump (54b). Cross sense pressure port for front pump (54a) should still be connected to gauge port for discharge pressure for rear pump (62b). Refer to Illustration 18 for correct plumbing.

   1. Increase input speed to the value in Step 6.a of the"Test Specifications". Increase pilot pressure to powershift pressure ports (53a) and (53b) according to Step 6.a of the"Test Specifications". Increase the pilot pressure to the cross sensing pressure port for the rear pump (54b) according to Step 6.a of the"Test Specifications". Increase discharge pressure on the rear pump according to Step 6.a of the"Test Specifications". Verify correct discharge flow from the rear pump. If the discharge flow is not correct, turn the adjustment screw for powershift pressure spring for rear pump (52b) until the discharge flow from the rear pump is within specifications. Verify that the case drain is less than or equal to the value in Step 6.a of the "Test Specifications"

   2. Increase the pilot pressure to the cross sensing pressure port for the rear pump (54b) according to Step 6.b of the"Test Specifications". Verify correct discharge flow from the rear pump. If the discharge flow is not correct, turn the adjustment screw for cross sensing for rear pump (55b) until the discharge flow from the rear pump is within specifications. Tighten locknut after discharge flow has been properly set.

      Reduce all pressures and input speed to zero.

Verify that all pressures and input speed are zero. Allow the component to cool. Remove component from the test bench. Drain the oil from the component. Plug and cap all ports.

Test Specifications

Tooling