Bench Test Procedure for Hydraulic Piston Pumps {5070} Caterpillar

Wheel Loader

980H (S/N: PF81-UP)

988H (S/N: A7A1-UP; BXY1-UP)

988K (S/N: T8E1-UP; L8X1-UP; LWX1-UP; TWX1-UP)

988K XE (S/N: E8X1-UP; EWX1-UP)

990K (S/N: DJK1-UP; A9P1-UP; M9P1-UP; K9X1-UP)

992K (S/N: 8801-UP; KK21-UP; RM21-UP; KK41-UP; RM51-UP; H4C1-UP; ZMX1-UP)

993K (S/N: LWA1-UP; Z4D1-UP; Z8D1-UP; Z9K1-UP; Z4Z1-UP; Z8Z1-UP)

994H (S/N: DWC1-UP)

994K (S/N: MM91-UP; MRK1-UP; SMX1-UP)

Introduction

© 2018 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 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 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 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	g01037439
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 2	g01037451
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	g01037458
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 4	g01037457
(28) "Flow meter 2" loop (29) "Flow meter 1" loop (30) "Flow meter 2" outlet (31) Signal pressure line (32) "Flow meter 2" inlet (33) Auxiliary pump oil supply (34) "Flow meter 1" inlet (35) "Flow meter 1" inlet

Illustration 5	g01046207
(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

Port Locations

Illustration 6	g03037538
Typical port locations and adjustments (49) Discharge port (50) Suction port (51) Pilot supply port (52) Case drain port (53) Electro-hydraulic valve (54) Pilot pressure

Illustration 7	g01301750
Hydraulic Schematic (49) Discharge port (50) Suction port (51) Pilot supply port (52) Case drain port (53) Electro-hydraulic valve (54) Pilot pressure (55) Electro-hydraulic pressure (56) Discharge pressure

1U-6392 Pressure Reducing Valve

Illustration 8	g01303822
1U-6392 Pressure Reducing Valve

Illustration 9	g01303823
1U-6392 Pressure Reducing Valve

Illustration 10	g01303826
1U-6392 Pressure Reducing Valve Schematic (57) Adjustment screw for the outlet pressure (58) Outlet port to tank (59) Gauge port for the inlet pressure (60) Port for the outlet pressure (61) Gauge port for the outlet pressure (62) Port for the inlet pressure

Pump Setup

Note: A power supply is required to operate the solenoid. The power supply should be capable of delivering 0 A to 1.7 A with an infinite setting in that range.

1. Mount the pump with the suction downward.

2. Connect the pump discharge port (49) to "Flowmeter 2" inlet on the test bench.

3. Open the oil supply valve in order to fill the pump. Purge all air from the suction line. Loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction hose.

4. Pour oil directly into a case drain port (52) until the case iscompletely full. Connect a hose to the upper case drain port (52).

5. Connect the case drain port (52) to an in-line flow meter.

6. Connect one end of a 6D-7727 hose assembly to pump discharge port (56). Connect the other end of the hose assembly to the port for inlet pressure (62) on the 1U-6392 pressure reducing valve. Connect a 8T-0860 Pressure Gauge to gauge port for inlet pressure (59). Connect one end of a 6D-7727 hose assembly to the pilot supply port (51). Connect the other end of the hose assembly to the port for outlet pressure (60) on the 1U-6392 pressure reducing valve. Connect a 8T-0856 Pressure Gauge to gauge port for outlet pressure (59). Vent outlet port (58) to atmosphere.

7. Connect the DC power supply to the electro-hydraulic valve (53).

8. 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 for proper rotation of the test bench.

Test Procedure

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	g01037413

1. Rotate the pump according to Step 1.a of the Test Specifications. Listen for abnormal noise. Verify that all connections are secure. Verify that all connections are not leaking. Check for leaks around shaft seals and control valves.

   1. Adjust the speed, discharge pressure, and signal current to the value in Step 1.a of the Test Specifications.

   2. This step will verify the operation of the control. This step will help purge the pump of air. Slowly cycle the current to the electro-hydraulic valve (53) to the value in Step 1.b of the Test Specifications 10 times in order to purge air from the pump. Run pump for an additional three minutes at the maximum current value in Step 1.b of the Test Specifications. Cycle the current to the electro-hydraulic valve (53) to the value in Step 1.b of the Test Specifications one more time to verify the flow is within the value in Step 1.b of the Test Specifications. Do not exceed the values for signal current in Step 1.b of the Test Specifications.
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   Illustration 12	g01301809
   Exploded view of control (63) Feedback spring (64) Control spool (65) Mounting plate and O-ring (66) Spring (67) Coil assembly (68) Spring washer (69) Cartridge assembly

2. Slowly change the pump operation to the values in Step 2 of the Test Specifications. If the pump's discharge flow is less than the value listed in step 2 of the Test Specifications replace the feedback spring. For 216-8978, 317-4294 and 385-0022 replace the feedback spring with 227-0201 Spring (Orange Stripe). For all other pumps replace the feedback spring with 338-0992 Spring (Red Stripe). If the actual flow exceeds the value listed in step 2 of the Test Specifications replace the feedback spring. For 216-8978, 317-4294, and 385-0022 replace the feedback spring with 227-0202 Spring (Light Blue Stripe). For all other pumps replace the feedback spring with 338-0991 Spring (Green Stripe). Refer to Illustration 12 for an exploded view of the control.

   Note: The torque for cartridge assembly (69) is 35 ± 3 N·m (26 ± 2 lb ft).

   Note: Springs 338-0991 and 338-0992 cannot be ordered separately. They must be ordered in 338-1105 Spring Kit. 338-1105 Spring Kit includes 270-7898 Spring, 338-0991 Spring, and 338-0992 Spring.

3. Follow the steps below in order to determine pump efficiency.

   1. Adjust the discharge pressure, speed, and signal current to the values in Step 3.a of the Test Specifications. Record the pump's discharge flow.

   2. Adjust the pump discharge pressure to the value in Step 3.b of the Test Specifications. Record the pump's discharge flow.

      For pumps 247-0666 and 313-7239, there should not be more than an 11 L/min (2.89 US gpm) decrease in the discharge flow between Step 3.a and Step 3.b. For all other pumps, the maximum difference should not be more than 15 L/min (3.96 US gpm). If the discharge flow decreases more than these values, the pump may not be functioning properly.

   Note: Lower speed and discharge pressure to zero.

   Note: Step 4, as written below, is for 216-8978, 317-4294, and 385-0022 only. For all other pumps, see Step 4 of the Test Specifications tables.

4. This step will verify the minimum flow. Disconnect the DC power supply from the electro-hydraulic valve (53). Adjust the discharge pressure to the value in Step 4 of the Test Specifications. Record the discharge flow. This is the minimum flow rate.

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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. Cap all ports. Plug all ports.

Test Specifications

Test Bench Tooling