Bleeding the Brake System
BLEEDING
HINT: If any work is done on the brake system or if air is suspected in the brake lines, bleed the system of air.
NOTICE: Do not let brake fluid remain on a painted surface. Wash it off immediately.
Brake System Bleeding:
1. Fill brake reservoir with brake fluid.
Check the fluid level in the reservoir after bleeding each wheel.
Add fluid, if necessary.
2. Bleed master cylinder.
HINT: If the master cylinder was disassembled or if the reservoir becomes empty, bleed the air from the master cylinder.
a. Disconnect the brake lines from the master cylinder.
Bleed Master Cylinder (Part 1 Of 2):
b. Slowly depress the brake pedal and hold it.
Bleed Master Cylinder (Part 2 Of 2):
c. Block off the outlet plug with your finger, and release the brake pedal.
d. Repeat b) and c) 3 or 4 times.
Loosen/Tighten Bleeder Plug:
3. Connect vinyl tube to wheel cylinder bleeder plug.
Insert the other end of the tube in a half-full container of brake fluid.
HINT: Begin air bleeding from the wheel cylinder with the longest hydraulic line.
4. Bleed brake line.
a. Slowly depress the brake pedal several times.
b. While an assistant depresses the pedal, loosen the bleeder plug until fluid starts to run out. Then close the bleeder plug.
Torque (bleeder plug): 11 Nm (8 ft. lbs.)
c. Repeat this procedure until there are no more air bubbles in the fluid.
5. Repeat procedure for each wheel.
6. Bleed Load Sensing Proportioning and Bypass Valve (LSP & BV).
Load SENSING PROPORTIONING AND BYPASS VALVE ON-VEHICLE INSPECTION
1. Set rear axle load.
Rear axle load (includes vehicle weight):
2WD:
1 ton: 850 kg (1,874 lbs.)
0.5 ton standard: 800 kg (1,764 lbs.)
0.5 ton option (soft ride): 850 kg (1,874 lbs.)
4WD: 1,050 kg (2,315 lbs.)
2. Install Load Sensing Proportioning Valve (LSPV) gauge Special Service Tool (SST) 09709-29018 or equivalent, and bleed air.
3. Raise front brake pressure to 7,845 kPa (1,138 psi
Rear brake pressure: 5,325 ± 490 kPa (772 ± 71 psi)
HINT: The brake pedal should not be depressed twice and/or returned while setting to the specified pressure. Read the value of rear brake pressure after holding the specified fluid pressure for 2 seconds. If the brake pressure is incorrect, adjust the fluid pressure.
4. If necessary, adjust fluid pressure.
a. Loosen the lock nut.
b. Adjust the length of the No.2 shackle.
Low pressure: Lengthen A
High pressure: Shorten A
Initial set: 120 mm (4.72 inch)
Adjustment range: 114 - 126 mm (4.49 - 4.96 inch)
HINT: One turn of the nut changes the fluid pressure as shown in the following specification.
7.5 kPa (11 psi)
c. Torque the lock nut.
Torque: 25 Nm (18 ft.lbs.)
d. If the pressure cannot be adjusted by the No.2 shackle, raise or lower the valve body.
Low pressure-Lower body
High pressure-Raise body
e. Torque the nuts.
Torque: 13 Nm (9 ft. lbs.)
f. Adjust the length of the No.2 shackle again.
If it cannot be adjusted, inspect the valve housing.
5. If necessary, check valve body.
a. Assemble the valve body in the uppermost position.
HINT: When the brakes are applied, the piston will move down about 0.8 mm (0.03 inch). Even at this time, the piston should not make contact with or move the load sensing spring.
b. In this position, check the rear brake pressure.
Front brake pressure
1,960 kPa (285 psi)
3,920 kPa (570 psi)
6,860 kPa (997.5 psi)
Rear brake pressure
1,960 kPa (285 psi)
2,352 ± 196 kPa (342 ± 28.5 psi)
2,940 ± 343 kPa (427.5 ± 50 psi)
If the measured value is not within the standard, replace the valve body.