Brake Master Cylinder: Service and Repair

Removing/Installing Master Cylinder Assembly:

1. Clean any dirt from around reservoir cap. Remove cap and remove brake fluid.
2. Disconnect 2 brake lines at master cylinder, taking care that brake fluid does not spill on painted surfaces, Fig. 1.
3. Remove mounting nuts and washers, and master cylinder.
4. Adjust clearance of booster piston rod to master cylinder piston as follows:
a. Push piston rod several times to make sure reaction disc is in place.
b. Measure with gasket in place on master cylinder and booster at atmospheric pressure.

Fig. 4 Tool J-34873 installation:

c. Set measuring tool J-34873 on master cylinder and push pin until it contacts piston, Fig. 2.

Fig. 5 Adjusting clearance between tool and piston rod:

d. Turn tool upside down and place on booster, Fig. 3. Adjust booster piston rod length until rod end contacts pin head.
5. Install master cylinder on studs. Install mounting nuts.
6. Connect hydraulic lines.
7. Fill reservoir with brake fluid.