Wheel cylinder (rear drum brake)

PROCEDURE

Drum brake wheel cylinder 1, 8 – protective boots; 2, 7 – pistons; 3, 6 – cups; 4 – spring; 5 – body; 9 – cap; 10 – bleeder valve

Replacing wheel cylinder cups WARNING If brake fluid leaks are visible, the wheel cylinder cups are replaced without removing the cylinder from the vehicle.

PROCEDURE 1. Remove the drum and brake shoes (see subsection 10.10).

2. Pinch off the brake hoses. 3. Unscrew bleeder valve 10 (see Drum brake wheel cylinder illustration). 4. Using a screwdriver, remove protective boots 1 and 8. 5. Remove the two pistons 2 and 7 with brake cups 3 and 6 and spring 4 from cylinder body 5. 6. Wash all parts and the cylinder with water and detergent, then dry them. 7. Inspect the working surfaces of the pistons and cylinder. WARNING If there are signs of wear, scoring or pitting on the working surfaces of the piston or cylinder, replace the wheel cylinder as a complete assembly.

8. Install new protective boots 1 and 8 on pistons 2 and 7, lubricated with brake fluid. 9. Install new brake cups 3 and 6 onto the grooves of pistons 2 and 7, lubricated with brake fluid, with the sealing lip facing into the cylinder. 10. Insert pistons 2 and 7 with spring 4 into wheel cylinder body 5. 11. Seat the edges of protective boots 1 and 8 in the corresponding recesses of wheel cylinder body 5. 12. Install brake shoes and drum (see subsection 10.10).

Removal of wheel cylinder PROCEDURE 1. Remove brake drum (see steps 1–7 of subsection 10.10).

2. Pinch off the brake hoses. 3. Unscrew bleeder valve 10. 4. Disconnect the brake hose fitting from the wheel cylinder. 5. Unscrew bolts 26 (see Rear drum brake illustration) securing wheel cylinder 19. 6. Pull the brake shoes slightly outward using a screwdriver and remove the wheel cylinder. Installation of wheel cylinder PROCEDURE 1. Install wheel cylinder 19 and tighten bolts 26. 2. Press the brake shoes back into place. 3. Loosen bleeder valve 10 (see Drum brake wheel cylinder illustration) if a new wheel cylinder is installed. 4. Install the brake hose fitting onto the wheel cylinder and secure it. 5. Remove the clamp from the brake hose. 6. Wait until brake fluid starts to flow from the bleeder valve opening in the wheel cylinder, then tighten the bleeder valve. 7. Install brake drum (see steps 13–18 of subsection 10.10).