Overhaul

Master Cylinder Overhaul

Disassembly Procedure




1. Remove the master cylinder. Refer to Master Cylinder Replacement Removal and Replacement.
2. Remove the brake fluid reservoir. Refer to Master Cylinder Reservoir Replacement Service and Repair.
3. Remove the seal ring from the cylinder bore.

Important: When removing the retaining ring, avoid damaging the piston or the cylinder wall.


Important: A welding rod or its equivalent can be used in a compensating port to keep the piston depressed.


4. Remove and discard the retaining ring from the cylinder body using a suitable screwdriver. The non-antilock brake system (ABS) master cylinder body is shown.




5. Remove the primary piston. The ABS master cylinder body is shown.
6. Carefully remove the secondary piston assembly, including the springs, from the master cylinder bore.

Assembly Procedure





Notice: Do not use abrasives in the master cylinder bore. Abrasives can damage the bore.

Important: Rubber parts and retaining rings must be discarded and replaced with new parts.


1. Clean all parts with denatured alcohol or clean brake fluid. Dry the parts with compressed air.
2. Inspect the master cylinder bore for scoring or corrosion. If scoring or corrosion is evident, replace the master cylinder body.
3. Lubricate the master cylinder bore with clean brake fluid. The non-ABS master cylinder is shown.
4. Carefully insert the secondary piston assembly bore until the secondary piston contacts the base of the cylinder body. Use a wood or a plastic drift, if necessary.
5. Insert the primary piston.




6. Press the pistons into the cylinder bore using a wooden or a plastic drift.

Important: When installing the new retaining ring, take care not to damage the cylinder bore.


7. Insert the new retaining ring into the groove in the cylinder bore. Remove the welding rod. The non-ABS cylinder body is shown.
8. Move the pistons backward and forward after installation to check for free movement.
9. Lubricate the seal ring and insert the seal into the cylinder bore. The open side must face outward until the seal rests on the piston.
10. Install the brake fluid reservoir to the master cylinder. Refer to Master Cylinder Reservoir Replacement Service and Repair.
11. Install the master cylinder assembly. Refer to Master Cylinder Replacement Removal and Replacement.
12. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle Service and Repair in General Information.
13. Bleed the braking system. Refer to Hydraulic Brake System Bleeding (Manual) Hydraulic Brake System Bleeding (Manual)Hydraulic Brake System Bleeding (ABS) Hydraulic Brake System Bleeding (ABS).
14. Lower the vehicle.