Bench Test Procedure for Hydraulic Piston Pumps{5070} Caterpillar

Vibratory Soil Compactor:

CP44 (S/N: MPC1-UP; M4P1-UP)

CS44 (S/N: M4C1-UP; M4S1-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 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 of 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 (on-line)

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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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.

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

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	g02028652
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	g02028653
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	g02028654
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 4	g02028656
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 outlet (34) Auxiliary oil inlet (35) "Flow meter 1" inlet

Illustration 5	g02028657
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

Port Locations

Illustration 6	g02044274
Typical pump port locations and pump adjustments. (49) Gauge port for system pressure (50) Case drain ports (51) Discharge ports (52) Adjustment for pump neutral (53) Gauge ports for the servo (54) Adjustment for control neutral (55) Gauge relief valve (56) Outlet to the filter (57) Inlet from the filter (58) Charge pressure gauge port

9U-5902 Rectifier Block

Illustration 7	g02028665
9U-5902 Rectifier Block Connections

Illustration 8	g02028668
9U-5902 Rectifier Block Schematic (59) High-pressure port (60) High-pressure outlet (61) High-pressure port (62) Low-pressure inlet

9U-5893 Heat Exchanger

Illustration 9	g02028670
9U-5893 Heat Exchanger Connections (63) Inlet "from flow meter loop" (64) Outlet "to rectifier block" (65) Water inlet (66) Water outlet

Connections for the Solenoid

Illustration 10	g02028672
Connectors that are used on type 1 pumps. (67) Ms connector (68) four pin Deutsch connectors (69) four pin Packard connectors (70) two pin Deutsch connectors

There are several different connectors that are used for supplying current to the solenoids. Four different types of connectors are used for the electronic displacement control. Refer to Illustration 10 for your specific type of connector. The Packard (69), low current deutsch connector (68), and ms connectors (67) all use a dual coil solenoid with four pin connectors. The high current deutsch connectors (70) use two single coil solenoids with two pin connectors for each solenoid.

Test the pumps with four pin connectors by first applying current from the power supply to terminals A and C. This will verify the operation in one direction of the pump. This also verifies the operation of the electronic displacement control. After the testing of A and C terminals is complete, feed current to B and D terminals to test the pump in the opposite direction.

Test the pumps with high current deutsch connectors by applying current from the power supply to one solenoid at a time. This will verify the operation in one direction of the pump. This also verifies the operation of the electronic displacement control. After the testing is completed on the first solenoid, apply current to the other solenoid in order to test the pump operation in the other direction.

Pump Setup

1. Mount the pump with a case drain port (50) facing upward.

2. Connect pump discharge port (51a) to the 9U-5902 Rectifier Block high-pressure port (59). Connect pump discharge port (51b) to the 9U-5902 Rectifier Block high-pressure port (61).

3. Connect the 9U-5902 Rectifier Block outlet (60) to the flow meter inlet of the test bench.

4. Connect the "flow meter outlet" to the 9U-5398 Heat Exchanger inlet (63) .

5. Connect the 9U-5398 Heat Exchanger outlet (64) to the low-pressure return (62) on the 9U-5902 Rectifier Block .

6. Connect the auxiliary oil outlet from the test bench to the inlet for the charge pump (57). The auxiliary oil supply should be able to produce 3000 kPa (435 psi) and 24.5 L (6.5 US gal).

7. Plug port (56) with a steel plug.

8. Connect an in-line flow meter to the case drain port (50) .

9. Purge all air from the suction line. Loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction hose.

10. Fill the pump case with oil before rotating. Pour oil directly into a case drain port (50) until the case is full.

11. Connect a power supply to the solenoid in order to operate the solenoid valve. Refer to Illustration 10 for the proper way to connect the power supply to the solenoid. The power supply should be able to deliver 0 mA to 1.5 A with an infinite setting in that range.

12. 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 the rotation of the test bench for proper direction.

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 11	g02028676
EDC Current Vrs Pump Flow

1. The following steps verify the operation of the charge pump and the operation of the charge relief valve.

   1. Supply auxiliary flow to port for auxiliary oil (57) according to the value in Step 1. Start rotating the pump according to Step 1a of the test specifications for several minutes in order to bring the oil to operating temperature. Listen for abnormal noise. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around the control valves.

   2. Increase the pump input RPM to the value in Step 1.b of the test specifications. Check the gauge port for the charge pressure (58). Compare the actual charge pressure with the value in Step 1.b of the test specifications. If the charge pressure is not within the test specifications, adjust the charge relief valve. Remove the plug for the charge relief valve (55) in order to adjust the shims. Add shims to the charge relief valve (55) in order to increase the charge pressure. Remove shims from the charge relief valve (55) in order to decrease the charge pressure.

2. The following steps verify the operation of the electronic displacement control and the initial point of pump stroke.

   1. Connect a hose between the gauge ports for the servo (53) in order to equalize servo pressure on each side of the stroking servo. Connect 8T-0860 Pressure gauge into the gauge ports for system pressure (49). Loosen the locknut for the adjustment screw for pump neutral (52) in order to adjust the pump neutral. Increase the load valve value to allow an increase in discharge pressure. Turn the set screw (52) until the gauge readings are equal. Turn the set screw (52) clockwise until there is a pressure increase in one of the pressure gauges. Record the position of the wrench. Turn the set screw (52) counterclockwise until there is a pressure increase on the other pressure gauge. Record the position of the wrench. Turn the set screw (52) clockwise to the halfway point between the two previous points.

   2. Connect 8T-0855 Pressure gauges into the gauge ports (53) of the servo. Loosen the locknut on the adjustment screw for the control neutral (54) in order to adjust the control neutral. Turn the set screw (54) until the gauges are equal. Turn the set screw (54) clockwise until there is a pressure increase in one of the pressure gauges. Record the position of the wrench. Turn the set screw (54) counterclockwise until there is a pressure increase on the other pressure gauge. Record the position of the wrench. Turn the set screw (54) clockwise to the halfway point between the two previous points.

   3. Slowly increase the input RPM and the current to the solenoid to the values in Step 2.c of the test specifications. This is the beginning of the pump's stroke. Both directions of operation for the pump must be tested. Some flow meters may not be able to read discharge flows at the initial or low flow rates. Slowly increase the solenoid current until the flow meter can read the discharge flow. Increase the discharge pressure to 3450 kPa (500 psi). Remove the solenoid current to the solenoid in order to ensure that the pump is not flowing. Slowly increase the solenoid current at a steady rate. Visually check discharge pressure until the pressure starts to rise above the charge pressure. This is the initial point of pump stroke.

3. Slowly increase the input RPM according to Step 3 of the test specifications. Slowly increase the current to the solenoid to the value in Step 3 in the test specifications. The pump must be operated in both directions in order to verify operation in either direction. Internally inspect the pump if the discharge flow does not match the value in Step 3 of the test specifications.

4. Slowly increase the pump discharge pressure to the value in Step 4 of the test specifications. Measure pump leakage. Calculate the total loss. If the total loss is higher than the allowable value in Step 4 of the test specifications, The pump may not be mechanically feasible.

   Subtract the discharge flow in Step 4 from Step 3. The result is your total loss.

   Example "Step 3 flow"162 L/min (42.8 US gpm) - "Step 4 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.

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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 of the ports.

Test Specifications

Test Bench Tooling