Brake Master Cylinder: Adjustments

NOTE: Master cylinder pushrod-to-piston clearance must be checked and adjustments made, if necessary, before installing master cylinder.

Using The Master Cylinder Pushrod Adjusting Gauge:

1. Set the special tool on the master cylinder body; push in the center shaft until the top of it contacts with the end of the secondary piston by turning the adjusting nut.
2. Without disturbing the center shaft's position, install the special tool upside down on the booster.
3. Install the master cylinder nuts and tighten to the specified torque.
4. Connect the booster in-line with a vacuum gauge 0-30 in Hg (0-760 mm Hg) to the booster's engine vacuum supply, and maintain a engine speed that will deliver 20 in Hg (500 mm Hg) vacuum.

Gauge Body And Adjusting Nut Clearance:

5. With a feeler gauge, measure the clearance between the gauge body and the adjusting nut as shown.
Clearance: 0-0.02 in (0-0.4 mm)

NOTE: If the clearance between the gauge body and adjusting nut is 0.02 in (0.4 mm), the pushrod-to-piston clearance is 0. However, if the clearance between the gauge body and adjusting nut is 0, the pushrod-to-piston clearance is 0.02 in (0.4 mm) or MORE. Therefore, it must be adjusted and rechecked.

Adjusting Master Cylinder Pushrod:

6. If clearance is incorrect, loosen the star locknut and turn the adjuster in or out to adjust.

NOTE:
^ Adjust the clearance while the specified vacuum is applied to the booster.
^ Hold the clevis while adjusting.

7. Tighten the star locknut securely.
8. Remove the special tool and install a new master cylinder rod seal in the booster.

Master Cylinder Pushrod Adjustment (Booster Removed From Vehicle):

9. Adjust the pushrod length as shown if the booster is removed.
10. Install the master cylinder, refer to Brakes and Traction Control/Brakes/Hydraulic System/Master Cylinder, Brakes/Service and Repair.
11. After installation, perform the following inspections and adjust if necessary.
^ Brake pedal height, refer to Pedal Height.
^ Brake pedal free play, refer to Pedal Height.