How to Change the Wheel Cylinders on a Car

Changing a wheel cylinder is an easy task when you know what you are doing.

The braking system on most vehicles has not changed much in the past 50 years. All drum braking systems are comprised of the same components. Brake shoes, springs and wheel cylinders are all basic components of the drum brake. Brake fluid enters the wheel cylinder when you apply pressure to the brake pedal. This in turn causes the wheel cylinder to exert pressure upon the brake shoes, which push out against the brake drums, essentially slowing and stopping the vehicle. When a wheel cylinder begins to leak fluid it should be replaced.

Things You'll Need

• Jack
• Jack stand
• Lug wrench
• Brake pliers
• Wrench
• Helper
• Brake fluid
• Shop rag

Instructions

1. Loosen the lug nuts. Identify the wheel cylinder you want to change and remove that tire and wheel. Loosen the lug nuts with a lug wrench while the tire is still on the ground.

2. Jack the vehicle until the tire is off of the ground. Place a jack stand under the chassis and lower the vehicle onto it. Remove the loosened lug nuts and remove the wheel. Set them to the side and out of the way.

3. Disassemble the brake. Remove the brake drum by pulling it free with your hands. Using brake pliers, remove the springs and clips that are retaining the brake shoes (every manufacturer has a different assembly method for their brakes). Remove the brake shoes. Inspect the shoes. Now is the time to replace any worn brake shoes.

4. Remove the wheel cylinder. Remove the brake line from the rear of the wheel cylinder with a wrench. Remove the two mounting bolts that go through the back side of the backing plate and into the wheel cylinder with a wrench. Pull the wheel cylinder from its mounting location.

5. Replace the wheel cylinder. Place the new wheel cylinder into position on the brake backing plate. Insert the mounting bolts through the backing plate and into the new wheel cylinder. Tighten with a wrench. Reassemble the brakes using new pads if needed. Reinstall the springs and clips with the brake pliers. Place the brake drum over the assembly. Replace the brake line into the wheel cylinder through the backing plate. Repeat these steps for each wheel cylinder that you want to change.

6. Bleed the brakes. Have a helper pump the brake pedal and hold it down while you crack the brake bleeder screw with a wrench. When the air squeezes out through the brake bleeder, quickly tighten it. Repeat this process of pumping the brakes up and holding the pedal down while you crack the bleeder and tighten it until you have no more air escaping from the bleeder only fluid. Top off the master cylinder with brake fluid by opening the hood and removing the master cylinder cap with your hands. Pour brake fluid into the master cylinder up to the full line and replace the cover. Close the hood.

7. Replace the tire. Wipe up any brake fluid that came out while bleeding the brakes with a clean shop rag. Replace the tire and wheel. Hand-tighten the lug nuts. Raise the vehicle off of the jack stands and remove them. Lower the jack and remove it. Tighten the lug nuts with the lug wrench in a crisscross pattern.

Tips & Warnings

• Replace the brake shoes when replacing a wheel cylinder. This will eliminate the need to remove the brakes again at a later time.

• Never work on vehicle that is on a jack with out supports under the chassis. You could be seriously injured or killed.

References

• 2 Car Pros: How to Replace Rear Brake Shoes and Drums