The rear brake cylinder is one of the numerous components of your brakes’ overall hydraulic system. Two internal pistons are positioned on each side of the rear brake cylinder. When you press down on your brake pedal, these pistons extend outward from the inside of the cylinder and come into contact with the inside of the brake drum, producing friction that brings the vehicle to a stop. If your cylinder blows and contaminates the brake shoes, cleaning it will not fix the problem; instead the rear brake cylinder must be replaced.
1. Loosen the lug nuts. Using the lug wrench, turn the lug nuts until they are approximately half-way off the tire. Loosening the lug nuts before you place the car on the jack allows you to loosen them without the tires turning. However, you don’t want to completely remove the lug nuts until the car is off the ground.
2. Secure the vehicle to keep it from rolling. In order to keep the vehicle from rolling while you’re working on it, place the wheel blocks in front and behind the front tires.
3. Lift the car. Place the jack under the rear frame of the car to lift the back end of the car off the ground. Once the rear of the car is in the air, place the jack stands under the frame — on both sides of the car — to secure it in place.
4. Lubricate the brake lines. Place the drain pan under the brake lines to catch any fluid that may leak out. Then spray the penetrating lubricant on the brake line that is attached to the wheel cylinder to make it easier to remove the brake drum.
5. Remove the brake drum. Start by removing the rubber plug on the brake plate to loosen the drum. Then pull the brake drum off. The drum can be difficult to get loose. While the lubricant helps, it’s often necessary to use a brake spoon and thin-headed screwdriver to pry the brake drum loose.
6. Remove the brake fitting. The brake fitting is adhered to the wheel cylinder and needs to be lubricated before you remove it. Simply spray the penetrating lubricant around the fitting and pry the it off the wheel cylinder. This should be done in a slow steady motion so you don’t damage the brake fitting.
7. Disconnect the upper brakes. Using the brake shoe pilers, carefully disconnect the upper brakes from the seated retainer. If you aren’t replacing the brake shoes, you still need to remove the brake shoe return springs on the two upper brakes. To do this simply disassemble the seated retainer using the brake shoe spring tool.
8. Remove the rear wheel brake cylinder and replace it with the new one. Remove the retaining bolts first, then the rear brake cylinder. Once the old piece is removed, replace it with the new brake cylinder and replace the retaining bolts.
9. Put the brakes back together. Start by putting the brake shoe return springs back on and reassembling the seated retainer. Then reconnect the upper brakes, put the brake fitting back on and replace the brake drum. Make sure you plug the rubber plug on the brake drum back in.
10. Top off the brake fluid and bleed the breaks. You need another person to help you bleed the brakes. Simply tell them to pump the brakes while you open the master cylinder’s bleeder screw. Repeat this process until the brakes feel normal in both firmness and height.