Bench Test Procedure for Hydraulic Piston Pumps{1387, 4306, 5070, 5084} Caterpillar

Introduction

© 2012 AVSpare 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.

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 AVSpare 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. In order to address an urgent need, use the following to relay your request to AVSpare 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 AVSpare "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 AVSpare Hydraulic Test Center

Illustration 1	g01127890
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	g01127891
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 AVSpare Hydraulic Test Bench

Illustration 3	g01127892
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 4	g01127894
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) Outlet for the auxiliary oil supply (34) Inlet for the auxiliary oil supply (35) "Flow meter 1" inlet

Illustration 5	g01127895
Control and Gauges for the Test Bench (36) Pressure for the auxiliary oil supply (37) Signal pressure (38) Control for signal pressure (39) "Flow meter 1" discharge pressure (40) Control for the pressure of the auxiliary oil supply (41) "Flow meter 2" discharge pressure (42) Control for the auxiliary oil supply (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

Illustration 6	g01127897
Typical port locations and adjustments (49) Suction port (50) Pilot assist port (51) Pump discharge port (52) Pilot supply port (53) Adjustment screw for maximum flow (54) Adjuster for flow control (55) Electro-hydraulic valve (56) Case drain port

Pump Pretest Set Up

Note: A power supply is required to operate the solenoid. The power supply should be able to deliver 0 mA to 1.5 A with an infinite setting in that range.

1. Mount the pump so that the control is facing downward and the suction flange is facing upward. Use a suction adapter in order to connect the pump to the test bench oil supply .

2. Connect the pump discharge port (51) to the test bench flow meter loop.

3. Open the oil supply valve in order to fill the pump. 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.

4. Fill the pump case with oil before rotating. Pour oil directly into a case drain port until the case is full.

5. Connect the case drain port (56) to an in-line flow meter.

6. Connect pilot supply oil from the test bench to the pilot supply port (52) and the pilot assist port (50) of the pump. Set the test signal pressure of the bench to the value in Step 1.a of the test specifications.

7. Connect the DC power supply to the electro-hydraulic valve (55) on the pump.

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

Note: The steps in the procedure correlate with the steps under the test specifications according to the 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 7	g00990423
Pump Discharge Flow Versus Solenoid Current

1. Start rotating the pump according to the RPM in Step 1 of the test specifications. Listen for abnormal noise. Verify flow from the pump. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around the control valve.

   1. Increase the pump discharge pressure to the value in Step 1.a of the test specifications. Adjust the maximum flow adjustment screw (53) if the actual flow is not within the specifications in Step 1 of the test specifications. Turn the adjustment screw for maximum flow (53) counterclockwise in order to increase the discharge flow. Do not turn the adjustment screw for maximum flow (53) more than three turns.

   2. Vary the current to the electro-hydraulic valve (55) in order to cycle the flow. Do not exceed the signal current values in Step 1.b of the test specifications. This will verify the operation of the control. This will also purge the pump of air. Cycle the pump at least ten times.

2. Slowly change the pump input RPM to the values in Step 2 of the test specifications. Slowly change the signal current to the electro-hydraulic valve (55) to the values in Step 2 of the test specifications. Adjust the adjustment screw for maximum flow (53) if the actual flow is not within the specifications in Step 2 of the test specifications. Turn the adjustment screw for maximum flow (53) counterclockwise in order to increase the discharge flow. Do not turn the adjustment screw for maximum flow (53) more than one turn. Do not exceed the set dimension of 32.5 mm (1.2795 inch). This is the maximum distance from the base of the adjustment screw to the end of the adjustment screw for maximum flow (53) .

3. Decrease the pump input RPM to the value in Step 3 of the test specifications. Slowly increase the signal current to the electro-hydraulic valve (55) to the value in Step 3 of the test specifications. Slowly increase the pump discharge pressure to the value in Step 3 of the test specifications. Adjust the adjuster for flow control (54) if the flow rate is not within the specifications in Step 3 of the test specifications. Turn the adjuster for flow control (54) clockwise in order to increase flow. Turn the adjuster for flow control (54) counterclockwise in order to decrease flow.

   Note: By turning the adjuster for flow control (54) by 1/6 of a turn, the flow rate will change approximately 30 L (8 US gal).

4. Follow the steps below in order to calculate the total loss. If the total loss is higher than the allowable value in Step 4.b of the test specifications, The pump may not be mechanically feasible. Internally inspect the pump.

   1. Change the discharge pressure and signal current to the electro-hydraulic valve (55) to the values in Step 4.a of the test specifications. Record the discharge flow of the pump.

   2. Increase the pump discharge pressure to the value in Step 4.b of the test specifications. Record the discharge flow of the pump.

      Subtract the discharge flow in Step 4.a from Step 4.b. The result is your total loss.

      Example "Step 4.a flow"162 L/min (42.8 US gpm) − "Step 4.b flow"158 L/min (41.7 US gpm) ="total loss" 4 L/min (1.1 US gpm). The "max. allowable loss" is 7.2 L/min (1.9 US gpm).

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

5. Change the discharge pressure and signal current to the electro-hydraulic valve (55) to the values in Step 5 of the test specifications. Record the discharge flow of the pump. This is the minimum flow rate.

6. Follow the steps below in order to verify the proper operation of the control.

   1. Change the discharge pressure and signal current to the electro-hydraulic valve (55) to the values in Step 6.a of the test specifications. Record the discharge flow of the pump.

   2. Change the signal current to the electro-hydraulic valve (55) to the values in Step 6.b of the test specifications. Record the discharge flow of the pump.

   3. Change the signal current to the electro-hydraulic valve (55) to the values in Step 6.c of the test specifications. Record the discharge flow of the pump.

   4. Change the signal current to the electro-hydraulic valve (55) to the values in Step 6.d of the test specifications. Record the discharge flow of the pump. Verify that the flow rate returned to the recorded value in Step 6.a.

      The pump or the pump control may not be mechanically feasible if the value of the pump's discharge flow are not within specifications. The pump or the pump control may not be feasible if the pump's discharge flow does not return to the value that was recorded in Step 6.a.

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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 ports.

Test Specifications

Test Bench Tooling