AP500F Asphalt Paver Propel System Caterpillar

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Diesel engine exhaust contains products of combustion which may cause personal injury. Always start and operate the engine in a well ventilated area, and, if in an enclosed area, vent the exhaust to the outside.

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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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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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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.

Specifications

Illustration 1	g03865587

Illustration 2	g03865594

Illustration 3	g03865615

Introduction

Charge pump pressure is controlled by charge relief valves. The charge relief valves protect the charge circuit by limiting the hydraulic pressure. This procedure provides the method to test and adjust the charge relief valves. The flushing valve should be tested and adjusted after checking the charge relief valves. The process to test and adjust the flushing valve is included in this procedure.

Required Tools

Illustration 4	g02571852

1. Connect one Tool (A2) to Tool (A3).

2. Connect each Tool (A3) to Tool (A1).

Illustration 5	g03850826

1. Connect Tool (C) to Tool (B).

Test Preparation

1. Drive the machine to a smooth, horizontal surface.
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   Illustration 6	g03862885

2. Move propel lever (4) to the NEUTRAL position.

3. Press parking brake switch (3) to change the status of the parking brake to "engaged". When the parking brake status is "engaged", an LED next to the parking brake switch will be illuminated.

4. Use travel mode switch (2) to select the PAVE mode. When the travel mode switch is set to PAVE mode, an LED next to pave symbol (1) will be illuminated.

   Note: The machine must be in PAVE mode to operate the screed lift system, hopper system, apron system, and auger lift system.

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   Illustration 7	g03862892

5. Press the screed raise switch (5) to lift the screed. Completely raise the screed.
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   Illustration 8	g03862916

6. Engage screed service lock mechanism (6) on both sides of the machine.
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   Illustration 9	g03862922

7. Use screed float switch (8) to place the screed in the FLOAT position. When the screed is in the FLOAT position, an LED next to the screed float switch will illuminate. Allow the tow arms to rest on screed service locks (6).

8. Press rpm decrease switch (9) for the throttle control once to operate the engine in low idle.
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   Illustration 10	g03862928

9. Shut off the engine. Either place machine power switch (10) in the OFF position or press and hold push to start switch (7) for 3 seconds. An LED next to the push to start switch will flash when the engine is in shutdown mode.

10. If the engine was shut down using push to start switch (7), move machine power switch (10) to the OFF position.
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    Illustration 11	g03863996

11. Remove four bolts (11) and washers. Open hopper doors (12).
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    Illustration 12	g03865587

12. Remove the cap from case drain tap (13) on the left propel pump. Connect one Tool (A2) to the drain tap.
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    Illustration 13	g03865594

13. Remove the cap from charge pressure tap (14) on the Left propel pump. Connect second Tool (A2) to the pressure tap.

Test Procedure

Charge Relief Test Procedure

1. Move machine power switch (10) to the ON position.

2. Press push to start switch (7) for 2 seconds to start the engine. An LED next to the push to start switch will flash when the engine is in start mode. When the engine has started, the LED will remain illuminated.

   Note: Only one attempt to start the engine is allowed per key cycle. A new key cycle is necessary to restart the process.

3. Operate the engine at low idle for a few minutes.
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   Illustration 14	g03863324

4. Press rpm increase switch (16) on the throttle control to place the engine in high idle. The engine speed should increase to 2200 rpm.

5. Monitor the hydraulic oil temperature on operator display (15). Operate the machine until the oil temperature reaches 43 ± 5.6 °C (110 ± 10 °F).

6. Record the pressure at charge pressure tap (14). The charge pressure should be 2300 ± 175 kPa (334 ± 25 psi).

7. Record the pressure at case drain tap (13). The case drain pressure should be 138 kPa (20 psi) to 410 kPa (59 psi) 410 kPa (59 psi).

8. Subtract the pressure that was recorded in Step 7 from the pressure that was recorded in Step 6. The differential pressure should be 1950 kPa (283 psi) to 2500 kPa (363 psi).

9. If the pressure is within the specified range, go to "Flushing Valve Test Procedure". If the pressure is not within the specified range, go to "Adjustment Procedure" "Charge Relief Adjustment Procedure".

Flushing Valve Test Procedure

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Illustration 15	g03864072

1. Rotate speed dial (17) to one quarter of maximum.

2. Press parking brake switch (3) to change the status of the parking brake to "disengaged".
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   Illustration 16	g03865127

3. Squeeze trigger (18), and move propel lever (4) slowly to the FULL FORWARD position. Observe the pressure at charge pressure tap (14). The pressure should momentarily decrease.

4. Move propel lever (4) to the NEUTRAL position. Then, squeeze trigger (18), and move propel lever slowly to the FULL REVERSE position. Observe the pressure at charge pressure tap (14). The pressure should momentarily decrease.

5. Move propel lever (4) to the NEUTRAL position. Move speed dial (17) to the MINIMUM position. Press parking brake switch (3) to place the parking brake in the ON position. When the parking brake is in the ON position, an LED next to the parking brake switch will illuminate.

6. Press rpm decrease switch (9) for the throttle control once to operate the engine in low idle.

7. Shut off the engine. Either place machine power switch (10) in the OFF position or press and hold push to start switch (7) for 3 seconds. An LED next to the push to start switch will flash when the engine is in shutdown mode.

8. If the engine was shut down using push to start switch (7), move machine power switch (10) to the OFF position.

9. If the flushing system operates as described in both directions, go to Step 10. If the flushing system does not operate as described in both directions, go to "Adjustment Procedure".

10. Remove the tooling.

11. Close hopper doors (12). Secure with four bolts (11) and washers.

Adjustment Procedure

Charge Relief Adjustment Procedure

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Illustration 17	g03865615

1. Loosen locknut (19) on the charge relief valve on the left propel pump. To increase pressure, rotate adjustment screw (20) clockwise. To decrease pressure, rotate the adjustment screw counterclockwise.

   Note: One turn of adjustment screw (20) changes the pressure by approximately 390 kPa (57 psi).

2. Hold adjustment screw (20) in place, and tighten locknut (19) to a torque of 52 N·m (38 lb ft). Go to "Test Procedure" "Charge Relief Test Procedure" Step 6.

Flushing Valve Adjustment Procedure

1. If the flushing pressure does not drop in either direction, replace the flushing relief valve. If flushing pressure drops more than 344 kPa (50 psi) or if flushing pressure drops below 1000 kPa (145 psi) in either direction, replace the flushing relief valve. Go to "Test Procedure", "Flushing Valve Test Procedure" and retest the flushing valve.

2. If the flushing system does not operate properly after the flushing relief valve is replaced, the propel motor may have internal leakage. If the flushing system performs as described in one direction but not the other, check the flushing spool. Go to "Test Procedure", "Flushing Valve Test Procedure" and retest the flushing valve.