2002/02/11 Caterpillar

Cold Planer:

PM-565B (S/N: 8GS210-UP)

The new procedure is for purging the air from the elevation leg cylinders after the cylinders have been serviced or after the 209-4734 Hydraulic Cylinders have been replaced. The air must be purged from the rod end and from the head end of the leg cylinder.

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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, 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.

Remove the Air from the Rod End

1. The 209-4734 Hydraulic Cylinder will require you to cycle the legs upward. The 209-4734 Hydraulic Cylinder will require you to cycle the legs downward. You must cycle the legs ten times. The procedure will remove the air that is trapped from the rod end of the cylinder.

Remove the Air from the Head End

1. Raise the front of the machine. Install leg lock supports for the two front legs. Lower the rear of the machine approximately 4 inches from the RAISED position. Lower the front legs on the leg lock supports. Raise the rear of the machine. Install the leg lock supports. Lower the rear of the machine on the leg lock supports. Use a 8S-7641 Tube and use a 4C-6486 Stand to support the main frame.

2. Loosen the filler cap assembly in order to release the pressure from the hydraulic tank.

3. Remove the covers from the front leg cylinders.

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Illustration 1	g00834510

4. Make sure that the machine is supported. Remove plug (1). Install the 148-4415 Test Coupling in the port. Install the 3J-1907 O-Ring Seal in the port.

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Illustration 2	g00835343
(2) 124-2111 Permanent Coupling (3) 4J-5477 O-Ring Seal (4) 8C-6866 Connector (5) 148-1886 High Pressure Coupler

5. Connect the assembly that is shown in illustration 2 to the 148-4415 Test Coupling .

Note: The next step may require two people to perform the operation.

6. Start the machine. Raise the machine. Remove the support stands. Remove the leg lock supports.

7. Actuate both switches downward for the front leg elevation when the engine is at 1100 RPM. When the machine starts to descend hold the knurled coupler and rotate the hose clockwise in order to open the high pressure port. Drain the oil and drain the air mixture in a bucket. Turn the hose counterclockwise in order to close the high pressure purge hose assembly when the machine is at the bottom of the stroke. You should perform the operation while switches for elevation are still actuating the cylinder. Raise the machine. Repeat the step several times until no air is discharged.

8. Disconnect the purge hose assembly and remove the purge hose assembly after step 7 is complete.

9. Install the 6V-0852 Dust Cap in order to protect the high pressure connector.

10. If the procedure is required, repeat step 2 through step 9 for the opposite front leg.

11. Reinstall the covers for the front leg cylinder.