Vacuum Brake Booster: Service and Repair

Brake Booster

REMOVAL

CAUTION:
Do not allow brake fluid to come in contact with vehicle body. If it does, wash off with water and wipe away completely.

1) Disconnect the ground cable from battery.
2) Drain brake fluid from the reservoir tank completely.
3) Remove the master cylinder assembly.

CAUTION:
In order to prevent the contact of the bracket and check valve, be sure to loosen the master cylinder mounting nut while holding the bracket with hand. Otherwise it may deform the bracket.





(1) Disconnect the fluid level gauge connector (a).
(2) Disconnect the brake pipe (b).
(3) Remove the nut (c), and slowly remove the master cylinder from the brake booster.





4) Remove the brake booster.

CAUTION:
^ Do not disassemble the brake booster.
^ If external force (1) is applied from above when brake booster is placed in this position, the resin portion as indicated by "P" may become damaged.





(1) Remove the clamp and remove the vacuum hose.





(2) Remove the clips and data link connector, and remove the instrument panel lower cover under.





(3) Remove the snap pin (a) and clevis pin (b), and remove the operating rod from the brake pedal.

NOTE:
^ Use special care when handling the operating rod. If excessive force is applied to the operating rod, the angle may change by ±3°, and it may result in damage to power piston cylinder.
^ Do not change the push rod length.





(4) Remove the nut and remove the brake booster.

NOTE:
^ Make sure that the booster shell and vacuum pipe are not subject to strong impacts.
^ Be careful not to drop the brake booster. If the brake booster is dropped accidentally, replace it.
^ Be careful when placing the brake booster on floor.





INSTALLATION

1) Check and adjust the operating rod of the brake booster.
(1) Measure the length between the brake booster mounting surface and clevis pin hole.
(2) If it is not within specification, loosen the lock nut, rotate the brake booster operating rod to adjust the rod length.

Specification L:
136.5 mm (5.37 in)





2) Install each part in the reverse order of removal.

CAUTION:
^ Apply grease to the snap pin to prevent the operating rod from wear.
^ Replace the clevis pin with new parts, and apply thin coat of NIGTIGHT LYW No. 2 grease to the clevis pin.
^ When installing the master cylinder assembly, replace the seal sub assembly with a new part, and install it to the brake booster.





^ Install the bracket at the position with sufficient clearance that it does not contact with the check valve.
^ Be sure to loosen the master cylinder mounting nut while holding the bracket with hand. Otherwise the bracket may deform.





Tightening torque:
Brake booster: 18 Nm (1.84 kgf-m, 13.3 ft-lb)
Master cylinder: 13 Nm (1.33 kgf-m, 9.6 ft-lb)
Brake pipe flare nut: 19 Nm (1.94 kgf-m, 14.0 ft-lb)
Operating lock nut: 22 Nm (2.24 kgf-m, 16.2 ft-lb)

3) Bleed air from the brake system.
4) Perform a road test to make sure the brakes do not drag.