Master cylinder — removal, overhaul and installation (Mazda Capella GC)

1. Purchase a master cylinder rebuild kit. The kit contains all necessary replacement parts. It is very important that the rubber seals are installed correctly and fit tightly. Be careful not to allow grease or solvents to come into contact with rubber parts.

2. Cover surrounding painted surfaces where brake fluid may splash, as the fluid will dissolve the paint.

3. Disconnect the brake system pipes. Place a rag or newspaper under the master cylinder to absorb any spilled fluid. Disconnect the fluid level sensor connector, remove the two master cylinder mounting nuts and remove the master cylinder from the vehicle (photo).





4. Drain any remaining liquid from the reservoir. Remove the reservoir by holding the master cylinder firmly and rocking the reservoir from side to side (photo).



5. Place the master cylinder in a vertical position (front end down), press the primary piston and remove the thrust ring.

6. Remove the primary piston and discard it.

7. Using a wooden dowel, push out the secondary piston. Remove the O-ring and mounting screw.

8. Turn the master cylinder upside down and tap it with a wooden block to remove the secondary piston.

9. Remove the spring from the front end of the secondary piston.

10. Remove the secondary piston rear strut, cylinder cover seal, valve gaskets and two seals located on the rear of the piston.

11. Remove the bushings, cover and float from the tank.

12. Clean the master cylinder and inspect the cap for corrosion and damage. If such defects are detected, replace the master cylinder housing. The exception is cases where the defects are very minor.

13. Inspect the tank for cracks and the bushings for wear. Replace components as necessary.



14. Before assembly, lubricate all components with clean brake fluid.

15. Install the valve gasket onto the front end of the secondary piston. Install the seal on the piston (open end forward).



16. Install the center seal on the secondary piston (open end forward).

17. Install the secondary piston rear seal (open end to the back).

18. Place the O-ring on the secondary piston mounting screw.

19. Lubricate the primary and secondary pistons with clean brake fluid.

20. Push the secondary piston assembly into the cylinder using a wooden dowel. Compress the spring slightly and insert the set screw.

21. Insert the primary piston with the spring seat facing forward. Compress the spring slightly and install the thrust ring.

22. Lubricate the reservoir bushings, place the reservoir on a hard surface and install the reservoir body onto the master cylinder.

23. Install the float assembly into the tank.

24. It is recommended to check the clearance between the primary piston and the brake booster push rod. Manufacturers have created a special tool for this purpose, No. 49 11002 765. The gap size should be 0.41-0.61 mm (the vacuum in the amplifier is released). Adjustment is made by rotating the brake booster push rod, which is secured with a lock nut.





25. After installing the master cylinder, it is necessary to bleed the entire brake system. Bleeding can be done faster if you fill the master cylinder with fluid before installing it. Fill the reservoir with brake fluid and slowly push the piston all the way into the cylinder using a wooden dowel or screwdriver. Before releasing the piston, plug the holes under the brake system pipes to prevent air from entering the master cylinder. Repeat the procedure until bubble-free brake fluid flows out of the cylinder. While pumping, monitor the fluid level in the reservoir and do not let it empty.

26. Install the master cylinder in place and tighten the brake pipe nuts by hand.

27. Install the master cylinder lock nuts and tighten them securely.

28. Tighten the brake pipe nuts securely and connect the fluid level sensor connector.

29. Bleed all brakes (see Chapter 15).