Bench Test Procedure for Hydraulic Piston Pumps{5070} Caterpillar

Bench Test Procedure for Hydraulic Piston Pumps{5070} [REHS3454]

HYDRAULIC SYSTEM

PUMP GP

Bench Test Procedure for Hydraulic Piston Pumps{5070}

1.1. Introduction

2.1. Canceled Part Numbers and Replaced Part Numbers

3.1. Safety

4.1. Summary

5.1. References

6.1. Connections for the Caterpillar Hydraulic Test Center

7.1. Connections for the Caterpillar Hydraulic Test Bench

8.1. Port Locations

9.1. 9U-5902 Rectifier Block

10.1. 9U-5893 Heat Exchanger

11.1. 198-4240 Electric Pressure Gauge Group

12.1. Pump Setup

13.1. Adjustment for Mechanical Zero Position

14.1. Adjustment for Hydraulic Zero Position

15.1. Test Procedure

16.1. Test Specifications

17.1. Test Bench Tooling

Excavator:
325B (S/N: 5LW1-UP)
Pneumatic Compactor:
CW14 (S/N: LTJ1-UP)
Paving Compactor:
CP-533D (S/N: AFC1-UP; 6AZ1-UP)
CP-563D (S/N: 9ZW1-UP; 5LZ1-UP)
CP-663E (S/N: ASF1-UP; DAF1-UP; AFL1-UP)
CS-533D (S/N: AET1-UP; 5CZ1-UP)
CS-563D (S/N: 9MW1-UP; 1SZ1-UP; 2RZ1-UP)
CS-573D (S/N: CMK1-UP; 2YZ1-UP)
CS-583D (S/N: 2CZ1-UP; 3GZ1-UP)
CS-663E (S/N: ASB1-UP; AEF1-UP; DAG1-UP)
CS-683E (S/N: DAD1-UP; ASG1-UP; AGR1-UP)
Vibratory Soil Compactor:
CP-563E (S/N: BWE1-UP; CNT1-UP)
CP-573E (S/N: ASY1-UP; ASZ1-UP)
CP56 (S/N: C5P1-UP; FCP1-UP)
CP64 (S/N: P7F1-UP; C6P1-UP)
CP74 (S/N: P8F1-UP; C8P1-UP)
CP76 (S/N: C7L1-UP; JCP1-UP)
CS-563E (S/N: ASA1-UP; CNG1-UP; MCP1-UP)
CS-573E (S/N: CEB1-UP; CNN1-UP)
CS-583E (S/N: DAJ1-UP; CNX1-UP)
CS54 (S/N: C5R1-UP)
CS56 (S/N: C5S1-UP; FCS1-UP)
CS64 (S/N: C7F1-UP; C6S1-UP)
CS74 (S/N: C8F1-UP; C8S1-UP)
CS76 (S/N: JCS1-UP; CYX1-UP)

Introduction

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Table 1
Revision	Summary of Changes in REHS3626
04	Added new Paving Equipment serial number prefix LTJ to document.
	Added 374-5346 Piston Pump Gp to document.
	Added ""Canceled Part Numbers and Replaced Part Numbers" " section to document.
	Added REHS1761 "Required Tooling for Bench Testing Hydraulic Components" to ""References" " section of document.

© 2012 AVSpare All Rights Reserved. This guideline is for the use of AVSpare 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 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 website. In order to address an urgent need, please 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

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Table 2
References
Media Number	Title
REHS1761	Required Tooling for Bench Testing Hydraulic Components
SEBF8810	Hydraulic Pump, Motor, and Cylinder Bench Test Procedure Reference Manual
SEHS8892	Operating Instructions for AVSpare 1U-9400 Series Hydraulic Test Center
NEHS0563	Tool Operating Manual for 9U-5000 Series Hydraulic Test Bench

Connections for the AVSpare Hydraulic Test Center

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Illustration 1	g01390282
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

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Illustration 2	g01390284
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

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Illustration 3	g01390288
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 (33) "Flow meter 1" inlet (34) Auxiliary pump oil supply (35) "Flow meter 1" inlet

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Illustration 4	g01390289
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

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Illustration 5	g01413842
Typical port locations and adjustments (49) Gauge ports for stroking pressure (50) Adjustment screw for hydraulic zero (51) Mechanical displacement lever (52) Adjustment screw for high-pressure cut (53) Inlet for charge oil (54) Discharge ports (55) Adjustment screw for crossover relief valve (56) Gauge port for charge pressure (57) Electrical connector for solenoid (58) Adjustment for charge relief valve (59) Gauge port for braking release pressure (60) Gauge ports for discharge pressure (61) Case drain ports (62) Adjustment screw for mechanical zero (63) Air purge ports

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Illustration 6	g01413873
Hydraulic schematic (49) Gauge ports for stroking pressure (53) Inlet for charge oil (54) Discharge ports (56) Gauge port for charge pressure (59) Gauge port for braking release pressure (60) Gauge ports for discharge pressure (61) Case drain ports

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Illustration 7	g03080556
Port Locations for 374-5346 (49) Gauge ports for stroking pressure (50) Adjustment screw for hydraulic zero (51) Mechanical displacement lever (52) Adjustment screw for high-pressure cut (54) Discharge ports (55) Adjustment screw for crossover relief valve (56) Gauge port for charge pressure (58) Adjustment for charge relief valve (60) Gauge ports for discharge pressure (61) Case drain ports (62) Adjustment screw for mechanical zero (63) Air purge port (75) Charge oil outlet (from internal charge pump) (76) Charge oil inlet from internal charge pump) (77) Suction (78) Pilot pressure

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Illustration 8	g03080716
Schematic for 374-5346 (49) Gauge ports for stroking pressure (51) Mechanical displacement lever (52) Adjustment screw for high-pressure cut (54) Discharge ports (55) Adjustment screw for crossover relief valve (56) Gauge port for charge pressure (58) Adjustment for charge relief valve (60) Gauge ports for discharge pressure (61) Case drain ports (63) Air purge port (75) Charge oil outlet (from internal charge pump) (76) Charge oil inlet (from internal charge pump) (77) Suction (78) Pilot pressure

9U-5902 Rectifier Block

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Illustration 9	g01413884
9U-5902 Rectifier Block Connections

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Illustration 10	g01413886
9U-5902 Rectifier Block Schematic (64) High-pressure port (65) High-pressure outlet (66) High-pressure port (67) Low-pressure inlet

9U-5893 Heat Exchanger

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Illustration 11	g01413888
9U-5893 Heat Exchanger Connections (68) Inlet "from flow meter loop" (69) Outlet "to rectifier block" (70) Water inlet (71) Water outlet

198-4240 Electric Pressure Gauge Group

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Illustration 12	g01413931
198-4240 Electric Pressure Gauge Group Connections (72) Pressure gauge (73) Red transducer 34500 kPa (5000 psi) (74) Blue transducer 3450 kPa (500 psi)

Pump Setup

Note: A power supply is required to operate the solenoid. The power supply should be capable of delivering 0 mA to 1.2 A with an infinite setting in that range. A power supply is not necessary for 314-5346. 314-5346 does not have a brake release valve as part of the pump.

Install pressure taps in the following test ports:
(49) Gauge ports for stroking pressure
(56) Gauge port for charge pressure
(59) Gauge port for brake release pressure (except for 374-5346 )
(60) Gauge ports for discharge pressure

Install a 8T-0856 Pressure Gauge into the gauge port for charge pressure (56). Install a 8T-0856 Pressure Gauge into the gauge port for brake release pressure (59) (except for 374-5346 ).

Connect a power supply to the connector for electric solenoid (57) (except for 374-5346 ).

Connect pump discharge ports (54a) and (54b) using "XT6" hoses to the 9U-5902 Rectifier Block high-pressure ports (64) and (66) .

Connect the 9U-5902 Rectifier Block outlet (65) to the flow meter inlet on the test bench.

Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (68).

Connect the 9U-5398 Heat Exchanger outlet (69) to the low-pressure return (67) on the 9U-5902 Rectifier Block .

Connect a water line to the water inlet (70) on the 9U-5398 Heat Exchanger . Connect a water line to the water outlet (71) on the 9U-5398 Heat Exchanger .

Connect the red transducer 34500 kPa (5000 psi) (73) or 8T-0860 Pressure Gauge to the pump's gauge ports for discharge pressure (60a) and (60b).

Connect auxiliary pump oil supply to the charge oil supply port (53). Be sure that the test bench can supply enough charge oil for steps 1 through 5.
Note: For 374-5346 connect oil supply (gravity oil supply, not auxiliary pump oil supply) to Suction port (77). Also, For 374-5346 connect a 1 inch "XT6" hose between Charge oil outlet (75) (from the internal charge pump) to Charge oil inlet (76) .

Vent the air purge port (63) to the atmosphere.

Fill the pump case with oil. Pour oil directly into case drain port (61a) until the case is completely full. Plug the air purge port (63) once case is full. Connect an in-line flow meter to the case drain port (61a). Direct flow from case drain port (61a) to test bench reservoir.

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

Turn the load control on the test bench completely clockwise in order to control the pump discharge pressure. Start rotating the pump at the value in Step 1. All units, except 374-5346, are not equipped with a charge pump. Be sure to sustain charge pump flow to Inlet for charge oil (53) (Suction port (77) for 374-5346 ) in Steps 1 through 5 of the Test Specifications. Vent the ports for the stroking pressure (49a) and (49b) to the atmosphere. This will equalize the pressure on the servo spool. If the mechanical zero adjustment is incorrect, a discharge pressure higher than the charge pressure may occur.
Note: Increase signal current to solenoid (57) until the braking valve is activated (except for 374-5346 ).

Turn the adjustment screw for the mechanical centering (62) clockwise. Continue to turn until a pressure of 200 psi above charge pressure is achieved. This pressure may be seen on the gauge port for the system pressure B (60a) or gauge port for the system pressure A (60b). Mark the position of the adjustment screw for the mechanical centering (62) .

Turn adjustment screw for the mechanical centering (62) counterclockwise until pressure increases on gauge ports (60b) or (60a). Mark the position of the adjustment screw for the mechanical centering (62) .

A mark should be placed halfway between position one and position two. Turn the adjustment screw for the mechanical centering (62) to the midpoint of both marks. There should be less than a 34.5 kPa (5 psi) pressure differential between pump gauge ports (60b) and (60a) .

Stop rotating the pump. Turn the load control on the test bench for pump discharge pressure counterclockwise. Allow the discharge pressure of the pump to decrease. Disconnect pressure gauges from ports (60b) and (60a) .

Adjustment for Hydraulic Zero Position

Connect two blue transducers 3450 (500 psi) or connect two 6000 kPa (870 psi) 8T-0856 Pressure Gauges into both gauge ports for stroking pressure (49a) and (49b) .
Note: Increase signal current to solenoid (57) until the braking valve is activated (except for 374-5346) .

Start rotating the pump to the value listed in step 1 of the test specifications. Turn the load control for the pump discharge pressure clockwise. This will allow pump discharge pressure to increase in the following steps.

Adjust the adjustment screw for hydraulic zero (50) until the pressure at the gauge ports for the stroking pressure (49a) and (49b) differ by less than 21 kPa (3 psi).
Note: Do not turn the adjustment screw for the hydraulic zero (50) more than 90 degrees in either direction.

Turn the load control for the pump discharge pressure counterclockwise. This will allow pump discharge pressure to decrease. Stop rotating the pump and allow pump pressure to dissipate. Disconnect the pressure gauges that are connected to the gauge ports for stroking pressure (49a) and (49b) .

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)

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Illustration 13	g01392457

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Illustration 14	g01392461

Start rotating the pump according to the RPM in Step 1 of the Test Specifications. Pumps without a charge pump will require auxiliary charge flow according to the value in Step 1 of the Test Specifications. Check the gauge port for charge pressure (56). Compare the charge pressure with the value in Step 1 of the Test Specifications. If the charge pressure is not within the test specifications, adjust accordingly. In order to adjust the charge pressure, shims must be added or removed to the charge relief valve (58). For 374-5346 an adjustment screw is present (no shims required for adjusting the charge relief valve). Verify the flow rates and listen for abnormal noise. Verify that all connections are secure. 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.

Slowly apply current to the electrical connector for solenoid (57) (except for 374-5346 ). Check the gauge port for braking release pressure (59) (except for 374-5346 ). Compare the brake release pressure with the value in step 2 of the Test Specifications (except for 374-5346 ). Increase the input RPM according to Step 2 of the Test Specifications. Shift the mechanical displacement lever (51) fully in either direction in order to acquire pump flow.

Slowly adjust the input RPM and discharge pressure to the values in Step 3 of the test specifications. Shift the mechanical displacement lever (51) fully in either direction. Verify that the discharge flow is within specifications. The pump may not be mechanically feasible if the actual flow is not equal to the value in step 3 of the Test Specifications.
Shift the mechanical displacement lever (51) in the opposite direction. Verify that the discharge flow is equal to the value in 3 of the Test Specifications.

Increase pump discharge pressure to the value in step 4 of the Test Specifications. Measure pump leakage at this point. Calculate the total loss. The pump may not be mechanically feasibly if the total loss is higher than the allowable value in step 4 of the Test Specifications.
Subtract the discharge flow that was recorded in Step 4 of the Test Procedure from the discharge flow that was recorded in Step 3 of the Test Procedure in order to find the total loss.
Example: Step 4 flow 162 L/min (42.8 US gpm) - "Step 3 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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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 during adjustment of the high pressure relief valve if recommended hose maintenance practices are not followed. Escaping fluid under pressure can penetrate body tissue causing serious injury, and possible death.

Adjustment of the high pressure cut or pressure override valve shall only be performed when the pump is operating at a zero discharge pressure condition. Continuation of the pump test procedure can be resumed when this high pressure adjustment is completed.

Increase the discharge pressure to the value in Step 5 of the Test Specifications. Turn the adjustment screw for the high pressure cut (52) until the actual high pressure cut out value is equal to the value in Step 5 of the Test Specifications. The discharge flow should be zero when the high-pressure cut is reached.

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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 or plug all ports.

Test Specifications

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Table 3
Part Number	159-9458
Rotation	Clockwise
Step	1	2	3	4	5
Input Speed	600	1000	2000	2000	2000
Discharge Pressure kPa (psi)	2900 (420) ⁽¹⁾	2900 (420) ⁽¹⁾	6890 (1000)	20000 (2900)	46000 (6670)
Discharge Flow lpm (gpm)	0	56 (14.8)	112 (29.6)	112 (29.6)	0
Auxiliary Charge Flow lpm (gpm)	9 (2.4)	9 (2.4)	9 (2.4)	9 (2.4)	9 (2.4)
Charge Pressure kPa (psi)	2900 (420)	2900 (420)	2900 (420)	2900 (420)	2900 (420)
Solenoid Current Amps	-	1.2	1.2	1.2	1.2
Brake Release Pressure	-	2900 (420)	-	-	-
Pump Loss Efficiency liter per minute (gpm)	Subtract the actual step 3 Discharge Flow from the actual step 4 Discharge Flow. This is the Total Loss.			4.5 (1.18)	-

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