Bench Test Procedure for Hydraulic Piston Pumps{3203, 5070} Caterpillar

Multi Terrain Loader:

267 (S/N: CMP700-UP)

267B (S/N: CYC1-399)

277 (S/N: CNC1200-UP)

277B (S/N: MDH1-1599)

287 (S/N: CNY1-UP)

287B (S/N: ZSA1-999)

Introduction

© 2015 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 CaterpillarDealer 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. In order 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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• 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 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	g01063311
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	g01063312
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	g01063314
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 4	g01093468
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 5	g01063316
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

Port Locations

Illustration 6	g01206228
Typical port locations and adjustments (49) Adjustment screw for the mechanical centering (front pump) (50) Port for the stroking pressure (front pump) (51) Gauge port for the charge pressure (front pump) (52) Gauge port for the system pressure B (front pump) (53) Gauge port for the control pressure (speed sensing) (54) Discharge port B (rear pump) (55) Gauge port for the system pressure B (rear pump) (56) Adjustment screw for the speed sensing valve (57) Adjustment for the charge pressure (58) Gauge port for the system pressure A (rear pump) (59) Adjustment screw for the port plate (rear pump) (60) Adjustment screw for the mechanical centering (rear pump) (61) Gauge port for the charge pressure (62) Adjustment screw for the port plate (front pump) (63) Port for the stroking pressure (rear pump) (64) Discharge port A (rear pump) (65) Port for the charge pressure (66) Case drain (67) Adjustment screw for the maximum displacement (rear pump) (68) Port for the stroking pressure (rear pump) (69) Discharge port B (front pump) (70) Discharge port A (front pump) (71) Case drain (72) Port for the stroking pressure (front pump) (73) Adjustment screw the maximum displacement (front pump) (74) Gauge port for the system pressure A (front pump)

Illustration 7	g01206229
Hydraulic Schematic (49) Adjustment screw for the mechanical centering (front pump) (50) Port for the stroking pressure (front pump) (51) Gauge port for the charge pressure (front pump) (52) Gauge port for the system pressure B (front pump) (53) Gauge port for the control pressure (speed sensing) (54) Discharge port B (rear pump) (55) Gauge port for the system pressure B (rear pump) (56) Adjustment screw for the speed sensing valve (57) Adjustment for the charge pressure (58) Gauge port for the system pressure A (rear pump) (59) Adjustment screw for the port plate (rear pump) (60) Adjustment screw for the mechanical centering (rear pump) (61) Gauge port for the charge pressure (62) Adjustment screw for the port plate (front pump) (63) Port for the stroking pressure (rear pump) (64) Discharge port A (rear pump) (65) Port for the charge pressure (66) Case drain (67) Adjustment screw for the maximum displacement (rear pump) (68) Port for the stroking pressure (rear pump) (69) Discharge port B (front pump) (70) Discharge port A (front pump) (71) Case drain (72) Port for the stroking pressure (front pump) (73) Adjustment screw the maximum displacement (front pump) (74) Gauge port for the system pressure A (front pump)

9U-5902 Rectifier Block

Illustration 8	g01205587
9U-5902 Rectifier Block Connections

Illustration 9	g01205590
9U-5902 Rectifier Block Schematic (75) High-pressure port (76) High-pressure outlet (77) Low-pressure inlet (78) High-pressure port

9U-5893 Heat Exchanger

Illustration 10	g01205596
9U-5893 Heat Exchanger Connections (79) Inlet (80) Outlet (81) Water inlet (82) Water outlet

Set up for the Front Pump

1. Install pressure taps on ports (50), (51), (52), (53), (55), (58), (61), (63), (68), (72), (74)

2. Install a pressure gauge on the gauge port for the charge pressure (61). Install a pressure gauge on the gauge port for the control pressure (speed sensing) (53) .

Note: Be sure to use XT-6ES rated hydraulic hose.

3. Connect pump discharge ports (69) and (70) to the 9U-5902 Rectifier Block high-pressure ports (75) and (78) .

4. Connect the 9U-5902 Rectifier Block outlet (76) to the flow meter inlet on the test bench.

5. Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (79) .

6. Connect the 9U-5398 Heat Exchanger outlet (80) to the low-pressure return (77) on the 9U-5902 Rectifier Block .

7. Connect a hose from discharge port B (54) to discharge port A (64). Connect the discharge ports in order to isolate the rear pump. The rear pump will not be tested.

8. Connect a hose from the port for the charge pressure (65) to the auxiliary oil outlet on the test bench. The auxiliary oil supply should be able to produce 3000 kPa (435 psi) and 56 L/min (14.8 US gpm).

9. Fill the pump case with oil. Pour oil directly into a case drain port (66) or (71) until the case is full.

10. Vent the case to the atmosphere. Make sure that the case drain flow is directed into the sump.

11. 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.

Mechanical Zero Position for the Front Pump

1. Start rotating the pump at the value in Step 2. This unit is not equipped with a charge pump. Be sure to sustain charge pump flow to port (65) in Steps 1 through 6 of the test specifications. Vent the ports for the stroking pressure (50) and (72) to the atmosphere. This will equalize the pressure on the servo spool. Install pressure gauges on ports (52) and (74). Turn the load control on the test bench for the pump discharge pressure "clockwise". Make sure that the load control is fully restricting discharge flow. A discharge pressure higher than charge pressure may occur if the mechanical zero adjustment is incorrect.

2. Turn the adjustment screw for the mechanical centering on the front pump (49) clockwise until pressure increases on the gauge port for the system pressure B (52) or gauge port for the system pressure A (74). Mark the position of the adjustment screw for the mechanical centering (front pump) (49) .

3. Turn adjustment screw for the mechanical centering (front pump) (49) counterclockwise until pressure increases on gauge ports (52) or (74). Mark the position of the adjustment screw for the mechanical centering (front pump) (49) .

4. A mark should be placed midway between position one and position two. Turn the adjustment screw for the mechanical centering (front pump) (49) to the midpoint of both marks. There should be less than a 34.5 kPa (5 psi) pressure differential between pump gauge ports (52) and (74) .

5. Turn the load control on the test bench for pump discharge pressure counterclockwise. Allow the discharge pressure of the pump to decrease. Stop rotating the pump and allow pump pressure to dissipate. Disconnect pressure gauges from ports (52) and (74) .

Testing the Front Pump Control

Note: The steps in the procedure correlate with the steps under the test specifications according to your specific part number.

Illustration 11	g01215772
Pump Flow Characteristics. (Q) Pump flow (R) Control pressure (2) Beginning of the stroke (3) End of full stroke

1. This step will verify correct charge pressure. This step will also ensure correct operation of the speed sensing valve. This can be accomplished without pump rotation. Be sure to sustain the auxiliary oil supply to port (65) in Steps 1 through 6 of the test specifications. Slowly increase the auxiliary oil supply to the value in the Step 1 of the test specifications. Be sure that the pressure on the gauge port for the charge pressure is equal to the value in Step 1 of the test specifications. Adjust accordingly with shims if the charge pressure does not agree with the value in Step 1 of the test specifications. Charge pressure must be set correctly before proceeding. Adjust the adjustment screw for the speed sensing valve (56) accordingly if the gauge port for the control pressure (speed sensing) (53) does not agree with the value in Step 1 of the test specifications.

2. Start rotating the pump according to the RPM in Step 2 of the test specifications. Connect the control pressure on the test bench to port (50) on the front pump. Vent the opposite stroking port (72) to the atmosphere. Slowly increase the control pressure to the value in Step 2 of the test specifications. This is the beginning of stroke on the pump. If the actual discharge flow is not correct, then the pump may not be mechanically feasible. Listen for abnormal noise. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around the control valve. Refer to Illustration 11.

   Note: Some flow meters may not be able to read initial discharge flows or low flow rates. Slowly increase the control pressure above the value in Step 2 of the test specifications. Continue increasing until flow begins to register.

3. Slowly increase the control pressure to the value in Step 3 of the test specifications. Increase the pump RPM to the value in Step 3 of the test specifications. The control pressure in Step 3 should initiate maximum pump displacement. The flow should agree with the value in Step 3 of the test specifications. Adjust the adjustment screw for maximum displacement (front pump) (73) accordingly. Refer to Illustration 11.

4. Increase pump discharge pressure to the value in Step 4 of the test specifications. Measure pump efficiency. 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.

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

Show/hide table

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 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.

5. The crossover relief valves will now be tested. Slowly increase the pump discharge pressure to the value in Step 5 of the test specifications. The discharge pressure should not exceed the value in Step 5 of the test specifications. If the discharge pressure exceeds the value in Step 5 of the test specifications, adjust accordingly. The pump may not be mechanically feasible if the discharge pressure cannot meet the value in Step 5 of the test specifications.

   Reduce RPM and all pressures to zero.

   Connect the control pressure to the port for the stroking pressure (72). Vent the opposite stroking port (50) to the atmosphere. Repeat Steps 2, 3, and 5 to test in reverse.

6. Proceed to ""Set up for the Rear Pump" ".

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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.

Set up for the Rear Pump

Note: Be sure to use XT-6ES rated hydraulic hose.

1. Connect pump discharge ports (54) and (64) to the 9U-5902 Rectifier Block high-pressure ports (75) and (78) .

2. Connect the 9U-5902 Rectifier Block outlet (76) to the flow meter inlet on the test bench.

3. Connect the flow meter outlet to the 9U-5398 Heat Exchanger inlet (79) .

4. Connect the 9U-5398 Heat Exchanger outlet (80) to the low-pressure return (77) on the 9U-5902 Rectifier Block .

5. Connect a hose from discharge port B (69) to discharge port A (70). Connect the discharge ports in order to isolate the front pump.

6. Connect a hose from the port for the charge pressure (65) to the auxiliary oil outlet on the test bench. The auxiliary oil supply should be able to produce 3000 kPa (435 psi) and 56 L/min (14.8 US gpm).

7. Fill the pump case with oil. Pour oil directly into a case drain port (66) or (71) until the case is full.

8. Vent the case to the atmosphere. Make sure that the case drain flow is directed into the sump.

9. 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.

Test Procedure for the Rear Pump

The ISO contamination rating of the hydraulic oil in the test bench should be at least 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)

Mechanical Zero Position for the Rear Pump

1. Start rotating the pump at the value in Step 2. This unit is not equipped with a charge pump. Be sure to sustain charge pump flow to port (65) in Steps 1 through 6 of the test specifications. Vent the ports for the stroking pressure (68) and (63) to the atmosphere. This will equalize the pressure on the servo spool. Install pressure gauges on ports (55) and (58). Turn the load control on the test bench for the pump discharge pressure "clockwise". Make sure that the load control is fully restricting discharge flow. A discharge pressure higher than charge pressure may occur if the mechanical zero adjustment is incorrect.

2. Turn the adjustment screw for the mechanical centering (rear pump) (60) clockwise until pressure increases on the gauge port for the system pressure B (55) or gauge port for the system pressure A (58). Mark the position of the adjustment screw for the mechanical centering (rear pump) (60) .

3. Turn adjustment screw for the mechanical centering (rear pump) (60) counterclockwise until pressure increases on gauge ports (55) or (58). Mark the position of the adjustment screw for the mechanical centering (rear pump) (60) .

4. A mark should be placed midway between position one and position two. Turn the adjustment screw for the mechanical centering (rear pump) (60) to the midpoint of both marks. There should be less than a 34.5 kPa (5 psi) pressure differential between pump gauge ports (55) and (58) .

5. Turn the load control on the test bench for pump discharge pressure counterclockwise. Allow the discharge pressure of the pump to decrease. Stop rotating the pump and allow pump pressure to dissipate. Disconnect pressure gauges from ports (55) and (58) .

Testing the Rear Pump Control

Note: The steps in the procedure correlate with the steps under the test specifications according to your specific part number.

Illustration 12	g01215772
Pump Flow Characteristics. (Q) Pump flow (R) Control pressure (2) Beginning of the stroke (3) End of full stroke

1. Step 1 has already been verified. Proceed to Step 2.

2. Start rotating the pump according to the RPM in Step 2 of the test specifications. Connect the control pressure on the test bench to port (68) on the front pump. Vent the opposite stroking port (63) to the atmosphere. Slowly increase the control pressure to the value in Step 2 of the test specifications. This is the beginning of stroke on the pump. If the actual discharge flow is not correct, then the pump may not be mechanically feasible. Listen for abnormal noise. Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around the control valve. Refer to Illustration 12.

   Note: Some flow meters may not be able to read initial discharge flows or low flow rates. Slowly increase the control pressure above the value in Step 2 of the test specifications. Continue increasing until flow begins to register.

3. Slowly increase the control pressure to the value in Step 3 of the test specifications. Increase the pump RPM to the value in Step 3 of the test specifications. The control pressure in Step 3 should initiate maximum pump displacement. The flow should agree with the value in Step 3 of the test specifications. Adjust the adjustment screw for maximum displacement (rear pump) (67) accordingly. Refer to Illustration 12.

4. Increase pump discharge pressure to the value in Step 4 of the test specifications. Measure pump efficiency. 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.

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

Show/hide table

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 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.

5. The crossover relief valves will now be tested. Slowly increase the pump discharge pressure to the value in Step 5 of the test specifications. The discharge pressure should not exceed the value in Step 5 of the test specifications. If the discharge pressure exceeds the value in Step 5 of the test specifications, adjust accordingly. The pump may not be mechanically feasible if the discharge pressure cannot meet the value in Step 5 of the test specifications.

   Reduce RPM and all pressures to zero.

   Connect the control pressure to the port for the stroking pressure (63). Vent the opposite stroking port (68) to the atmosphere. Repeat Steps 2, 3, and 5 to test in reverse.

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NOTICE
Both Pumps will be tested at the same time

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Illustration 13	g01274883
Set up for the block port timing test. (50) Port for the stroking pressure front pump (53) Gauge port for the control pressure speed sensing (57) Gauge port for the charge pressure (58) Gauge port for the system pressure A rear pump (63) Port for the stroking pressure rear pump (65) Port for the charge pressure (74) Gauge port for the system pressure A front pump (83) Control Pressure

6. Port plating timing will now be set. The front and rear pumps will be set at the same time. Block discharge ports (69), (70), (54) and (64) with steel plugs. Install pressure gauges on ports (52) (55) (58) and (74). Connect the control pressure on the test bench to the ports for stroking pressure (50) and (63) on the front and rear pump using a Tee. Vent the opposite stroking ports (72) and (68) to the atmosphere.

   Increase the RPM to the value in Step 6 of the test specifications. Increase the control pressure to the value in Step 6 of the test specifications. Turn the adjustment screw for the port timing (62) in order to adjust the discharge pressure on the front pump. The discharge pressure should equal the value in Step 6 of the test specifications. Record the actual pressure shown on the front pump pressure gauge.

   Note: The port timing screws are a sensitive adjustment. Do not turn the adjustment screws greater than the full adjustment range. The full adjustment range is 180 degrees. Turning beyond the full adjustment range will cause internal pump damage.

   Turn the adjustment screw for the port timing (59) in order to adjust the discharge pressure on the rear pump. The discharge pressure can be seen on the rear pump pressure gauge. The discharge pressure should equal the actual discharge pressure recorded from the front pump.

   Repeat Step 6 to verify port timing in the reverse direction. Connect the control pressure to the ports for the stroking pressure (68) and (72). Vent the opposite stroking ports (50) and (63) to the atmosphere. It may be necessary to split the difference if the pressure differential is greater than 3000 kPa (435 psi). Be sure to adjust the high pressure down to the value in Step 6. Adjust the lower pressure up to the value in Step 6 of the test specifications.

   Note: Be sure to double check the forward direction once more if an adjustment was made in the reverse direction.

Show/hide table

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.

Test Specifications

Test Bench Tooling