BobCat S70 – MAIN RELIEF VALVE – Testing Without Auxiliaries

NOTE: The following procedure is for checking the main relief valve only. Use this procedure
when it is known that the hydraulic pump is in good working condition. If the hydraulic pump
is not working correctly, refer to checking the output of the hydraulic pump. (See HYDRAULIC PUMP Page 20-60-1.)

The tools listed will be needed to do the following procedure:

MEL 10003 – Hydraulic Tester
MEL 10006 – Hydraulic Test Kit

Lift and block the loader. (See Procedure Page 10-10-1.)

Disconnect the rod end hydraulic hose (Item 1) [Figure 20-30-1] from the tilt cylinder.

Connect the IN port of the hydraulic tester to the rod end hydraulic hose (Item 1) [Figure 20-30-1].

Connect the OUT port of the hydraulic tester to the rod end of the tilt cylinder port. (Where the hydraulic hose was disconnected.)

Check the hose routing, from the tester, for clearance while doing this procedure.

Sit in the operator seat, lower the seat bar and fasten the seat belt.

Start the engine and run at low RPM. Push the bottom (heel) of the right foot pedal to retract the tilt cylinder.

Check for hydraulic leaks. Be sure the tester is showing flow.

Increase the engine speed to full RPM.

Push the bottom (heel) of the right foot pedal until the system relief pressure is reached.

The correct pressure for the main relief valve is 2000 PSI (138 bar).

If the relief valve pressure is not correct, stop the engine. Replace the main relief valve. (See Removal And Installation on Page 20-30-3.)

When the test is complete return the foot pedal to neutral position, reduce the engine RPM to idle.

Stop the engine.


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