Komatsu D31EX-21, Operation & Maintenance Manual, Page: 170 / 256

TROUBLESHOOTING
OPERATION
3-118
8. Set the brake release pump in front of the operator.
RELEASING BRAKE
CAUTION
When a machine is towed, the brakes must be fully released. If the brakes are partially applied, this may
lead to overheating and damage to the brakes.
To release the brakes, set the pump pressure to 2.7 to 3.1 MPa (28 to 32 kg/cm²).
If the pump pressure exceeds 3.1 MPa (32 kg/cm²), the components of the brake may be damaged.
When towing, leakage from the oil pressure circuit will cause the pump pressure to go down with time.
Always keep the pump pressure above 1.5 MPa (15 kg/cm²) when towing. If the pressure goes below 1.5
MPa (15 kg/cm²) during the towing
operation, stop the operation, pump the handle of the brake release pump, and raise the pump pressure to
2.7 to 3.1 MPa (28 to 32 kg/cm²).
When towing, do not use the brakes to control the travel speed of the machine. This will further damage
the brakes and there may be defective operation of the brake system.
1. Check that lever (1) of the bypass valve is at the FULLY
CLOSED position (B). If it is not at the FULLY CLOSED
position (B), turn it in a downward direction until it stops.
2. Operate handle (2) of the brake release pump and send
pressure oil to the brake circuit until it reaches the specified
pressure.
Specified pump pressure: 2.75 to 3.14 MPa (28.0 to 32.0
kg/cm²)
REMARK
If it is necessary to move the brake release pump during the
operation, hold lever (3) under handle (2) and move the pump.
3. It is now possible to tow the machine.
Remove the blocks, and tow the machine at a speed of
less than 2 km/h.