AP-655C and BG-2255C Asphalt Pavers Drag Conveyor and Auger Conveyor Systems Caterpillar

Testing and Adjusting the Piston Pumps in the Upper and Lower Pump Stacks

Introduction

The swashplate angle for the piston pumps in the upper and lower pump stacks is controlled by the electrical displacement control valve (EDC valve). This control valve is designed so that the angular position of the swashplate is proportional to the DC input current to the solenoids on the EDC valve. The following procedure will verify whether the swashplate is at a zero angle position when there is no DC current input to the solenoids.

There are two piston pumps in each pump stack. As a result, you will be checking a total of four neutral adjustments. There are two neutral adjustments for the upper pump stack and there are two neutral adjustments for the lower pump stack.

Required Tools

Hydraulic test procedures may be performed using either one of the following test equipment:

• Caterpillar DataView

• Standard Pressure Gauges

Caterpillar DataView

Illustration 1	g00920192
Caterpillar DataView Caterpillar DataView is a PC based diagnostic tool. The Caterpillar DataView accepts a maximum of nine standard Caterpillar sensors for measurements on the machine. The signal is transmitted to a personal computer and the information is displayed.

ReferenceRefer to Tool Operating Manual, NEHS0662, "Caterpillar DataView" for additional information about using Caterpillar DataView.

Standard Tooling

Illustration 2	g00934707

Use the tools in Table 3 to complete the following test procedure.

Test Procedures

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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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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

1. Perform the following procedure before you follow the test procedure:
   • Park the machine on a level area that is clear from equipment and material.

   • Verify that the service brake system and the parking brake system are in good working condition.

   • Block the drive wheels in both directions.

   • Move the propel lever to the neutral position.

   • Apply the parking brake.

   • Make sure that the hydraulic oil is at the correct operating temperature.

2. Start the engine. The engine should be at high idle with engine coolant at 37.8 °C (100 °F). Warm the hydraulic oil to a minimum temperature of 37.8 °C (100 °F).

   ReferenceSee Specifications, Systems Operation/Testing and Adjusting, "General Testing and Adjusting Information" for information on warming the oil.

3. Stop the engine.

Test Procedure for the Piston Pumps in the Upper Pump Stack

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Illustration 3	g00930635

1. The upper pump stack is located in the pump compartment on the left side of the machine. Remove the access cover.

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Illustration 4	g00931456
(1) Upper pump stack (2) Lower pump stack (3) Propel pumps (4) Pump drive

2. Locate upper pump stack (1) .

   Perform Step 3 through Step 10 for left drag conveyor piston pump.

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Illustration 5	g01526603
Upper Pump Stack (5) Port "M4" (6) Port "M5" (7) Solenoid

3. Remove the plugs at port "M4" (5) and port "M5" (6) . Retain the plugs for reassembly.

4. Install Tooling (B) at port "M4" (5) and port "M5" (6) .

5. Install Tooling (A) on Tooling (B) .

6. Disconnect the control wires on solenoid (7) for the EDC valve.

   Note: Mark the wiring for reconnecting.

7. As the EDC valve is disconnected, a fault will appear on the Caterpillar Monitoring System. Reset the system after the test and adjust procedures.

8. Start the engine. Run the engine at high idle.

9. The pressures at Tooling (A) should be equal. If the pressure gauges do not show the same pressure on both sides of the servo piston, an adjustment needs to be made. Perform the procedure in "Adjustment Procedure for the Piston Pumps in the Upper and Lower Pump Stacks".

10. If the pressure is equal, the test is completed.

Note: Perform Step 11 through Step 18 for the right auger conveyor piston pump.

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Illustration 6	g01526607
Upper Pump Stack (8) Solenoid (9) Port "M5" (10) Port "M4"

11. Remove the plugs at port "M5" (9) and port "M4" (10) . Retain the plugs for reassembly.

12. Install Tooling (B) in port "M5" (9) and port "M4" (10) .

13. Install Tooling (A) on Tooling (B) .

14. Disconnect the control wires from solenoid (8) on the EDC valve.

    Note: Mark the wiring for reconnecting.

15. As the EDC valve is disconnected, a fault will appear on the Caterpillar Monitoring System. Reset the system after the test and adjust procedures.

16. Start the engine. Run the engine at high idle.

17. The pressures at Tooling (A) should be equal. If the pressure gauges do not show the same pressure on both sides of the servo piston, an adjustment needs to be made. Perform the procedure in "Adjustment Procedure for the Piston Pumps in the Upper and Lower Pump Stacks".

18. If the pressure is equal, the test is completed.

Test Procedure for the Piston Pumps in the Lower Pump Stack

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Illustration 7	g00930635

1. The lower pump stacks are located in the pump compartment on the left side of the machine. Remove the access cover.

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Illustration 8	g00931456
(1) Upper pump stack (2) Lower pump stack (3) Propel pumps (4) Pump drive

2. Locate lower pump stack (2) .

   Perform Step 3 through Step 10 for the right drag conveyor piston pump.

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Illustration 9	g01526617
Lower Pump Stack (11) Port "M4" (12) Port "M5" (13) Solenoid

3. Remove the plugs at port "M4" (11) and port "M5" (12) . Retain the plugs for reassembly.

4. Install Tooling (B) to port "M4" (11) and port "M5" (12) .

5. Install Tooling (A) on Tooling (B) .

6. Disconnect the control wiring from solenoid (13) for the EDC valve.

   Note: Mark the wiring for reconnecting.

7. As the EDC is disconnected, a fault will appear on the Caterpillar Monitoring System. Reset the system after the test and adjust procedures.

8. Start the engine. Run the engine at high idle.

9. The pressures at Tooling (A) should be equal. If the pressure gauges do not show the same pressure on both sides of the servo piston, an adjustment needs to be made. Perform the procedure in "Adjustment Procedure for the Piston Pumps in the Upper and Lower Pump Stacks".

10. If the pressure is equal, the test is completed.

Note: Perform Step 11 through Step 18 for the left auger conveyor piston pump.

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Illustration 10	g01526624
Lower Pump Stack (14) Solenoid (15) Port "M5" (16) Port "M4"

11. Remove the plugs at port "M5" (15) and port "M4" (16) . Retain the plugs for reassembly.

12. Install Tooling (B) in port "M5" (15) and port "M4" (16) .

13. Install Tooling (A) on Tooling (B) .

14. Disconnect the control wiring on solenoid (14) for the EDC valve.

    Note: Mark the wiring for reconnecting.

15. As the EDC valve is disconnected, a fault will appear on the Caterpillar Monitoring System. Reset the system after the test and adjust procedures.

16. Start the engine. Run the engine at high idle.

17. The pressures at Tooling (A) should be equal. If the pressure gauges do not show the same pressure on both sides of the servo piston, an adjustment needs to be made. Perform the procedure in "Adjustment Procedure for the Piston Pumps in the Upper and Lower Pump Stacks". Stop the engine.

18. If the pressure is equal, the test is completed.

Adjustment Procedure for the Piston Pumps in the Upper and Lower Pump Stacks

Illustration 11	g00932332
(17) Neutral adjustment screw (18) Neutral adjustment screw

There are two neutral adjustment screws for each piston pump. The following adjustment procedure will explain the procedure for adjusting one of the neutral adjustment screws. Use the following procedure to adjust the other three neutral adjusting screws.

Note: Leave Tooling (B) and Tooling (A) in place for the following adjustment procedure.

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Illustration 12	g00931640
(18) Neutral adjustment screw (19) Locknut

1. Start the engine. Make sure that the hydraulic oil is at the correct operating temperature.

2. Loosen locknut (19) on neutral adjustment screw (18) .

3. Check the pressure at Tooling (A) at port "M5" and port "M4".

4. Observe the gauge with the highest pressure reading. Turn neutral adjustment screw (18) in the clockwise or counterclockwise direction until the other gauge has increased to the same reading. Take note of the amount the screw has been turned. Once the other gauge reading has increased to the pressure that was observed on the first gauge, turn the adjustment screw back 1/2 the distance.

   Note: Ensure that the angular position of the wrench is noted during this adjustment. This may be done by making a mark on the pump for orientation.

5. Hold neutral adjustment screw (18) stationary. Tighten locknut (19) to a torque of 13.6 to 24 N·m (10 to 18 lb ft).

6. Repeat Step 2 through Step 5 if neutral adjustment screw (18) turns during Step 5.

7. Shut off the engine.

8. Reconnect the control wiring to the solenoids for the EDC valve. Clear any faults that may appear on the Caterpillar Monitoring System.

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

9. Observe the machine and the operating temperature. A minimum of fifteen minutes should pass before you attempt to proceed to the next steps. This will allow the machine and the components to cool.

10. Remove Tooling (A) from Tooling (B) .

11. Remove Tooling (B) from ports "M4" and "M5".

12. Insert the plugs back into ports "M4" and "M5".