725 and 730 Articulated Trucks Steering, Suspension, and Body Hoist Hydraulic Systems Caterpillar

Park the machine on a level surface. There must be sufficient overhead clearance so that the dump body can be fully raised. Move the parking brake control to the ENGAGED position and shut off the engine. Install the steering frame lock. Refer to Operation and Maintenance Manual, SEBU7347, "Steering Frame Lock".

Testing the Relief Pressure (Lower)

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Illustration 1	g01037761

1. Install a pressure gauge on the test fitting. The pressure gauge must be capable of measuring 21000 kPa (3000 psi).

2. Start the engine and run the engine at low idle.

3. Move the hoist control to the LOWER position. When the body is in contact with the rear frame, hold the hoist control in the LOWER position and record the pressure that is displayed on the pressure gauge. This is the relief pressure (lower).

   The relief pressure (lower) should be 7584 ± 690 kPa (1100 ± 100 psi).

   If the relief pressure (Lower) is setting 7584 ± 690 kPa (1100 ± 100 psi), proceed to step 4.

   If the relief pressure (lower) is not 7584 ± 690 kPa (1100 ± 100 psi), the relief pressure (lower) must be adjusted. Move the hoist control to the FLOAT position and shut off the engine.

4. Use the following procedure to adjust the pressure relief valve (lower) (3d) :
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   Illustration 2	g01037760
   The relief valve (lower) is located in hoist control valve (3) toward the front of the machine.

   1. loosen the locknut (3gg) .

   2. Rotate the adjustment screw (3hh) clockwise in order to increase the relief valve pressure setting.

      Rotate the adjustment screw (3hh) counterclockwise in order to decrease the relief valve pressure setting.

   3. Tighten locknut (3gg) .

   4. Repeat the procedure from step 2.

5. Move the hoist control to the FLOAT position.

6. Shut off the engine and remove the pressure gauge from the machine.