PL83 and PL87 Pipelayers Engine Supplement Caterpillar

Pressure Release Procedure

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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 work tools have been lowered to the ground, 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.

1. Start the engine.

2. Move the machine to a smooth horizontal location that is away from other machines and personnel.

3. Make sure that all hydraulic functions are operating properly.

4. Lower all attachments to the ground.

5. Place the counterweight in the stored position.

6. Permit only one operator on the machine. Keep all other personnel away from the machine.

7. Engage the parking brake.

8. Stop the engine.
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   Illustration 1	g03831661

9. Install counterweight locking bolt (1), as shown.

   Note: Do not start the engine at this time.

10. Turn the ignition key to the ON position.
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    Illustration 2	g03851207

11. Make sure that hydraulic shutoff switch (2) is in the position that allows operation of the implements.

12. Move hydraulic control lever (3) to all positions so that the pressure in the hydraulic system is released.
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    Illustration 3	g03851206

13. Press check valve (4) in order to release the hydraulic tank pressure.

14. The pressure in the system has now been released and lines or components can be removed.