When the wheel cylinder is replaced, the leaks will stop and eventually bring back the performance of you system like new. First and foremost you have to know the type of wheel cylinder inside your vehicle. Most aluminum cylinders will be hard to rebuild and should be replaced but still, with special precautions and procedures, can still be rebuilt. Although, wheel cylinders that have too much corrosion should be replaced with a new one to avoid problems in the future.
Step 1 - Lift Car
Use jack stands and a floor jack so you can access the wheel cylinder. Take off the wheels for better access.
Step 2 - Remove Brake Drum
There will be times that drums will be hard to remove due to rust building around the area. If so, take a hammer and try to break it free from the rust. Avoid hammering to much to avoid damaging or denting the brake drum.
Step 3 - Remove Return Springs
Remove springs that hold the brake shoes against the wheel cylinder using the brake spring tool. These are long springs connecting the brake shoe to the pivot pin that is just above the wheel cylinder. Remove brake shoes.
Step 4 - Remove Components of Wheel Cylinder
This means the pistons, cup seals, spring and dust boots. When you get a wheel cylinder kit, new replacements cup seals and dust boots will be included.
Step 5 - Hone Wheel Cylinder
The inside should be honed with a wheel cylinder hone. This should be attached to an electric drill if the wheel cylinder is made of steel or cast iron. Never hone aluminum wheel cylinders. It will only add corrosion and wear if you do since aluminum wheel cylinder’s surface is already hard and anodized. If this is the type of your wheel cylinder, you can just clean the inside with water and soap using a Scotch Brite pad to remove dirt and debris inside the cylinder bore.
Step 6 - Clean and Dry the Parts
As soon as the wheel cylinder is honed, wash with water and soap to remove honing residue and then dry. After cleaning, apply clean brake fluid to the inside of the wheel cylinder bore and rubber cup. Apply liberally.
Step 7 - Insert Spring
The spring will go inside the bore of the wheel cylinder. Place cup seals and pistons inside each cylinder bore. Then follow with the cylinder dust boots outside the wheel cylinder.
Step 8 - Reposition Brake Shoes
You are ready to reinstall the return spring using a brake spring tool. Never use pliers or side cutter or a screwdriver to reinstall the return spring. You can damage the spring this way or even injure yourself.
Step 9 - Reinstall Brake Drum
Take your service manual and check how to bleed the brakes. It will depend on the brand and make of the car.
Step 10 - Reinstall Wheels
Once the wheel has been installed, you may lower you car down from the jack and take the car for a test drive. If you are uncertain of this procedure, always contact your professional mechanic.