CP76 and CS76 Vibratory Compactors Propel System Pump Synchronization - Test and Adjust Caterpillar


Pump Synchronization - Test and Adjust
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------ WARNING! ------

Personal injury can result from rotating and moving parts. Stay clear of all rotating and moving parts.

Never attempt adjustments while the machine is moving or the engine is running unless otherwise specified.

The machine must be parked on a level surface and the engine stopped.

Attach a "Do Not Operate" or similar warning tag to the start switch and controls before servicing, repairing, or making adjustments to the machine.

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------ WARNING! ------

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or near the machine.

To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

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------ WARNING! ------

Personal injury can result from hydraulic oil pressure and hot oil.

Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.

Make sure all of the attachments have been lowered, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

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NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.

Refer to Special Publication, NENG2500, "AVSpare Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in AVSpare machines.

Dispose of all fluids according to local regulations and mandates.


Table 1
Required Tools    
Tool     Part
Number    
Description     Qty    
A     8T-0861     Pressure Gauge

0 to 60000 kPa (0 to 8700 psi)    
4    
171-1879 Fitting Adapter     4    
187-3547 Fitting     4    
B     177-7863     Hose As     4    
187-3546 Quick Disconnect Coupler     8    
C     4C-6500     Digital Thermometer     1    

  1. Drive the machine to a smooth, horizontal surface in a large open area.



    Illustration 1g01407630

  1. Move propulsion lever (1) to the NEUTRAL position.



    Illustration 2g01407609

  1. Move parking brake switch (2) to the ON position.



    Illustration 3g01407610

  1. Move throttle switch (3) to the LOW IDLE position.



    Illustration 4g01407660

  1. Move engine start switch (4) to the OFF position.



    Illustration 5g01408900

  1. Remove bolts (5) and remove right cover plate (6) .



    Illustration 6g01408904

  1. Remove bolts (7) and remove left cover plate (8) .

  1. Connect Tool (A) to Tool (B). Make four sets of Tool (A) and Tool (B) .



    Illustration 7g01410956

    The Drum Pump is Shown From Left Side.




    Illustration 8g01410958

    The Axle Pump is Shown From Left Side.

  1. Connect one Tool (B) to each of the following pressure taps. Mark each gauge for identification:

    • Forward pressure tap (8) (drum pump)

    • Reverse pressure tap (7) (drum pump)

    • Forward pressure tap (9) (axle pump)

    • Reverse pressure tap (10) (axle pump)

  1. Move engine start switch (4) to the START position. Release the switch when the engine starts.

  1. Operate the engine at low idle for few minutes. Move throttle switch (3) to the HIGH IDLE position.

  1. Monitor hydraulic oil temperature with Tool (C). Operate the machine until the oil temperature reaches 43 ± 5.6 °C (110 ± 10 °F).



    Illustration 9g01410960

  1. Move shift switch (11) to the LOW SPEED position. Move parking brake switch (2) to the RELEASE position.

  1. Move propulsion lever (1) in the forward direction. Position the propulsion lever in the FULL FORWARD position. Record the pressure at forward pressure tap (8) for the drum pump and forward pressure tap (9) for the axle pump.

  1. Move propulsion lever (1) in the reverse direction. Position the propulsion lever in the FULL REVERSE position. Record the pressure at reverse pressure tap (7) for the drum pump and at reverse pressure tap (10) for the axle pump.

  1. Move propulsion lever (1) to the NEUTRAL position.

  1. Move shift switch (11) to the HIGH SPEED position.

  1. Move propulsion lever (1) in the forward direction. Position the propulsion lever in the FULL FORWARD position. Record the pressure at forward pressure tap (8) for the drum pump and at forward pressure tap (9) for the axle pump.

  1. Move propulsion lever (1) in the reverse direction. Position the propulsion lever in the FULL REVERSE position. Record the pressure at reverse pressure tap (7) for the drum pump and at reverse pressure tap (10) for the axle pump.

  1. Move propulsion lever (1) to the NEUTRAL position.

    Table 2
    Example of Test Pressures for Pump Synchronization    
    Pressure Tap for Axle Pump     Pressure Tap for Drum Pump     Speed and Direction    
    Low High    
    Forward Reverse     Forward     Reverse    
    (9)     -    
    6900 kPa (1000 psi)    
    Charge Pressure    
    7600 kPa (1100 psi)    
    Charge Pressure    
    -     (8)    
    6200 kPa (900 psi)    
    Charge Pressure    
    7200 kPa (1050 psi)    
    Charge Pressure    
    (10)     -     Charge Pressure    
    5900 kPa (850 psi)    
    Charge Pressure    
    6900 kPa (1000 psi)    
    -     (7)     Charge Pressure    
    6900 kPa (1000 psi)    
    Charge Pressure    
    7600 kPa (1100 psi)    

    Note: The values that are shown above are for example only. The actual pressures will vary depending on the conditions at the work site.

  1. Move throttle switch (3) to the LOW IDLE position.

  1. Move parking brake switch (2) to the ON position.

  1. Move engine start switch (4) to the OFF position.

  1. The differential pressure should be less than 1500 kPa (220 psi) in each test condition. If the pressure is inside the specified range for each test condition, go to Step 31. If the pressure is outside the specified range and the tie rod has not been adjusted during this procedure, go to Step 25. If the tie rod has been adjusted during this procedure but the pressure remains outside the specified range, go to Step 26.



    Illustration 10g01410961

    The Drum Pump is Shown From Left Side.

  1. Raise the cab. Refer to Disassembly and Assembly, KENR6413, "Cab - Tilt". Disconnect tie rod (12) from the displacement control lever on the drum pump. Make sure that the displacement control valve in the drum pump is in the NEUTRAL position. Also, make sure that the displacement control valve in the axle pump is in the NEUTRAL position. If necessary, adjust the length of the tie rod, and connect the tie rod to the displacement control lever on the drum pump. Lower the cab. Refer to Disassembly and Assembly, KENR6413, "Cab - Tilt". Go to Step 10.

  1. If the pressure differential in HIGH SPEED is greater than 1500 kPa (220 psi), go to Step 27. If the pressure differential in HIGH SPEED is within the specified range, go to Step 28.



    Illustration 11g01410963

    Axle Motor




    Illustration 12g01410966

    Drum Motor

  1. Adjust the motor which has the lower system pressure by turning minimum displacement adjustment screw (13) or (15) out one-half turn. This will decrease the motor displacement. At this point, the pressure differential should decrease. Go to Step 28.

  1. If the pressure differential in LOW SPEED is greater than 1500 kPa (220 psi), go to Step 29. If the pressure differential in LOW SPEED is within the specified range, go to Step 31.

  1. Adjust the motor which has the higher system pressure by turning maximum displacement adjustment screw (14) or (16) out one-half turn. This will increase the motor displacement. At this point, the pressure differential should decrease.

  1. Go to Step 10.

  1. Remove two sets of Tool (A) and Tool (B) from the drum pump. Remove two sets of Tool (A) and Tool (B) from the axle pump.

  1. Replace cover plates (6) and (8). Install bolts (5) and (7) .

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