 |
|
Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin. |
| 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. |
Note: Before you perform this procedure, release the pressure from the steering system and from the braking system. Also, make sure that the steering frame lock is installed.
| Piston Pump (Brake) Pressure | |
|---|---|
| Test | Specification |
| Brake oil pressure | |
| One rotation of adjustment screw (5) | |
| Torque for compensator nut (4) | |
This test outlines the procedure to test and adjust the brake oil pressure for the front brakes and the rear brakes.
| |
| Illustration 1 | g02726620 |
| Required Tools | ||||
|---|---|---|---|---|
| Tool | Item | Qty | Part No | Description |
| B2 | B1 | 1 | 8T-0860 | Pressure Gauge
(0 TO 40,000 kPa (0 TO 5,800 psi)) |
| B2 | 1 | 6V-3989 | Fitting | |
| B3 | 2 | 6V-4143 | Quick Connect Coupler | |
| B4 | 1 | 177-7862 | Hose As
|
|
Reference: For the correct procedure for machine preparation, refer to Testing and Adjusting, "System Pressure - Release".
| |
| Illustration 2 | g03886411 |
|
Diagnostic Plate (2) Pressure test port for front brakes (3) Pressure test port for rear brakes (5) Service brake control valve (6) Pressure test port for rear brake accumulator (7) Pressure test port for front brake accumulator | |
The diagnostic pressure ports for the brake system are located under and behind the cab.
- Remove the dust cap on pressure port (2) and install tooling (B).
- Start the engine and allow the pump to reach the high-pressure cutoff. Do not apply the service brakes. The pressure of the oil should be
15000 ± 345 kPa (2175 ± 50 psi) . - Stop the engine. Release the pressure from the steering system and from the braking system.
- Remove the dust cap on pressure port (3) and install a
0 to 28000 kPa (0 to 4000 psi) pressure gauge. - Start the engine and allow the pump to reach the high-pressure cutoff. Do not apply the service brakes. The pressure of the oil should be
15000 ± 345 kPa (2175 ± 50 psi) .Note: The oil pressure at pressure port (2) and at pressure port (3) should be similar. If the pressures at both locations are not similar, there may be a malfunctioning check valve, a loose fitting or a damaged hydraulic line.
- If the pressure is within the specification, stop the engine. Release the pressure from the steering system and from the braking system and remove the pressure gauge.
If the pressure is not within the specification, leave the pressure gauge connected and adjust the pressure compensator valve on the brake pump.
|
|
The drive shaft rotates between the torque converter and the transmission whenever the engine is running. Contact with the rotating shaft can result in personal injury or death. The rotating shaft is located under the implement and steering pumps. Do not allow personnel into the pump bay area behind the cab when the engine is running. |
- Open the access doors behind the cab. The brake pump is located on the engine side of the torque converter housing.
Show/hide table
Illustration 3 g03886432 Brake Pump
(1) Brake pump
(8) Pressure compensator valveShow/hide table
Illustration 4 g03886435 Pressure Compensator Valve for the Brake Pump
(1) Brake pump
(8) Pressure compensator valve
(4) Nut
(9) Adjustment screw - Loosen nut (4) and rotate adjustment screw (9) by a small amount.
Note: One rotation of adjustment screw (9) changes the pressure by approximately
2755 kPa (400 psi) . Turning the adjustment screw clockwise increases the pressure. Turning the adjustment screw counterclockwise decreases the pressure. - Start the engine and allow the pump to reach the high-pressure cutoff. Do not apply the service brakes. The pressure of the oil should be
15000 ± 345 kPa (2175 ± 50 psi) . - If the pressure of the oil is within the specification, proceed to Step 7.
If the pressure of the oil is not within the specification, stop the engine, release the pressure from the steering system and the braking system.
Reference: For the correct procedure for releasing the system pressure, refer to Testing and Adjusting, "System Pressure - Release".
- Repeat Steps 2 through 4 until the pressure is correct.
- Stop the engine. Hold adjustment screw (9) and tighten nut (4) to a torque of
9 ± 1 N·m (80 ± 9 lb in) . - Stop the engine. Release the pressure from the steering system and from the braking system and remove the pressure gauge.
