GM Prizm/Nova 1985-1993 Repair Guide

Wheel Cylinders



See Figure 1

If wheel cylinders are leaking or seized, they should be replaced. The units are inexpensive enough to make replacement a better choice than repair. Even if the pistons and seals can be replaced, the internal bore can rarely be restored to perfect condition. A faulty repair can reduce braking effort on the wheel or cause a leak which soaks the brake shoes in fluid.

When inspecting the cylinders on the car, the rubber boots must be lifted carefully and the inner area checked for leaks. A very slight moistness - usually coated with dust - is normal, but any accumulation of fluid is evidence of a leak and must be dealt with immediately.

  1. Remove the rear brake shoes and hardware.
  3. Using a line wrench if possible, disconnect the brake line from the back of the cylinder. This joint may be dirty or corroded. Clean it off and apply penetrating oil if necessary. Do not allow the threaded fitting to twist the brake line. Plug or tape the brake line to prevent leakage.
  5. Remove the 2 bolts holding the wheel cylinder to the backing plate. Loosen these gently to prevent breaking the bolts.

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Fig. Fig. 1: Wheel cylinder components

  1. Remove the wheel cylinder from the backing plate. Drain the remaining fluid into a container.
  3. Install the new cylinder onto the backing plate and tighten the mounting bolts to 7.5 ft. lbs. (90 inch lbs.).
  5. Carefully reinstall the brake line and tighten it to 11 ft. lbs.
  7. Reinstall the shoes and hardware.
  9. Install the brake drum and wheel.
  11. Bleed the brake system. Repeated bleedings may be needed to eliminate all the air within the line and cylinder.