Rebuild

DISASSEMBLY

1. Clean the outside of the master cylinder and remove the filler cover and gasket. Drain and discard any brake fluid that remains in the cylinder.

Removing Snap Ring:

2. Depress the primary piston and remove snap ring from retaining groove at the rear of the master cylinder bore.

3. Remove primary piston assembly from the master cylinder bore and inspect for seal damage or twisting. Record condition of piston assembly on repair order and discard assembly.

4. Remove the secondary piston assembly by directing compressed air into the outlet port at the blind end of the bore while plugging the other outlet port. Inspect for seal damage or twisting. Record condition of piston assembly on repair order and discard assembly.

5. Inspect the master cylinder bore for signs of etching, pitting, scoring or other damage.

a. If bore is damaged, discard and replace with new master cylinder assembly. Do not attempt to hone bore.

b. If bore is not damaged, rebuild master cylinder assembly using the proper repair kit and the procedure outlined below.

ASSEMBLY

Master Cylinder:

1. Clean the master cylinder body with clean isopropyl alcohol to remove any contamination.

2. Dip the repair kit piston assemblies in clean heavy duty brake fluid or brake assembly lube to lubricate seals.

3. Carefully insert the complete secondary piston assembly in the master cylinder bore.

4. Carefully insert the primary piston assembly in the master cylinder bore.

5. Depress the primary piston and install the snap ring in the cylinder bore groove.

6. On manual brake vehicles, install the push rod retainer onto the push rod and install into the primary piston. Make sure the retainer is properly seated and holding the push rod securely.

7. Install the cover and gasket on the master cylinder assembly and secure into position with the retainer.

For additional information see Fundamentals and Basics.