| Required Tools | ||
|---|---|---|
| Part Number | Part Description | Qty |
| 177-7861 | Hose As | 1 |
| 6V-4143 | Couplers | 2 |
| 8T-0856 | Pressure Gauge | 1 |
 |
|
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. |
|
|
Personal injury or death can result from machine movement. Place blocks in front of and behind the wheels to make sure the machine does not move while the parking brakes are disengaged. |
| NOTICE |
|---|
|
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, PERJ1017, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
- Move the machine to a hard, level surface.
- Engage the parking brake and stop the engine.
- Put blocks in front and behind the wheels.
Show/hide table
Illustration 1 g00915684 Parking brake control valve
(1) Pressure tap (pilot oil pressure) - Connect a 177-7861 Hose As and an 8T-0856 Pressure Gauge to pressure tap (1).
- Start and run the engine at low idle rpm. Disengage the parking brake. With the oil at normal operating temperature, the pressure should read
3515 ± 70 kPa (510 ± 10 psi) . - If the pressure is not correct, engage the parking brake and stop the engine.
- Depress the service brake pedal at least 25 times to release any pressure in the brake accumulators.
- Move the joystick control lever several times through the full range of travel to release any pressure in the implement pilot circuits.
- Move the STIC steering control lever several times in both directions to release any pressure in the steering system.
- Press and hold the breaker relief valve to release any pressure in the hydraulic tank.
Show/hide table
Illustration 2 g00915685 (2) Pilot oil pressure reducing valve Show/hide table
Illustration 3 g00915686 (2) Pilot oil pressure reducing valve
(3) Locknut
(4) Adjusting screw - Loosen locknut (3) and turn adjusting screw (4) on pilot oil pressure reducing valve (2). Turn adjusting screw (4) clockwise to increase pressure and counterclockwise to decrease pressure. The correct pressure is
3515 ± 70 kPa (510 ± 10 psi) - Repeat Step 5.
- If the pressure reading is correct, engage the parking brake and stop the engine. Remove the test equipment from pressure tap (1). Place the protective cover over the pressure tap.
- If the pressure reading is not correct, engage the parking brake and stop the engine. Repeat Steps 7 through 12.
