How to Replace Rear Brakes
Replacing brakes is fairly simple if you have a basic mechanical aptitude. Many vehicles have a combination of both disc and drum brakes, usually disc in the front and drum in the rear. The main difference is easy to spot; disc brakes use hydraulic pressure to clamp brake pads on a rotating disc affixed to the wheel by the lug bolts. Drum brakes use either hydraulic or mechanical pressure to force shoes (pads) outward to create friction on the inside of a drum affixed to the wheel with lug bolts. Many hydraulic systems will also have a mechanical backup on the drum brakes for the parking brake.
If you are a do-it-yourself mechanic, the best tool you can own is a detailed repair manual for your vehicle. It's cheap. Go buy it. The most common repair needed on drum brakes is shoe replacement. I will outline the basic procedure here, but be warned; vehicles vary by make, model, and year. This is intended as a basic informational guide only. In the following example, we are working on a set of rear drum brakes.
Start by blocking the front wheels, ensuring the car will not roll. Make sure the transmission is in Park (in gear if manual) and the parking brake is released. Loosen the lug nuts on both sides, then raise the car using a floor jack if available. Use jack stands to support both sides securely, preferably on the frame or axle to ensure stability. Leave the floor jack in place, but do not trust it to support the vehicle alone. Next, remove the wheels and tires on both sides. They make a nice seat while working on the brakes, so leave them on the floor in a convenient position.
The drums should come off fairly easily; with some vehicles you may need to remove a dust cap, and a cotter pin and wheel nut, with others the lug nuts are all that holds the drum in place. Go ahead and remove the drum on both sides. If you forget how to put everything back together, you can refer to the other side to jog your memory. Don't laugh, it happens.
Once you have the drums off, you can see how the mechanics of the brakes work. There is an adjuster, which tightens the brakes as they wear, and a wheel cylinder that applies braking pressure. There are also springs which keep the shoes in a retracted position when not braking. Now is the moment of truth. Take a close look at the system, and your accompanying repair manual. Be honest with yourself, and decide if you should proceed, because this is the point of no return. If you're comfortable, proceed.
The nice thing about replacing drum brakes is often you can get by without removing brake lines or opening the bleeder valves. Keeping your hydraulic system closed simplifies and shortens your repair time considerably. Go ahead and remove the springs holding your shoes in, using vice grip pliers to create the necessary slack. This should allow you to remove the shoes. While you're in there, make sure you clean everything thoroughly with brake cleaner, and lubricate your friction points, as well as the adjuster, as per your vehicle manufacturer recommendations. Now is also a good time to back up that auto adjuster to make plenty of room for the new shoes.
Now you have a decision to make. Inspect the inside of the drum, and the wheel cylinder. It's a good idea to either turn or replace the drum while you're in there. See a machine shop for help with turning the drum; it will make your shoes last longer and wear more evenly. When you put the new shoes in, and begin reassembling the brakes, take a look at the other side for a reference. You can use c-clamps to hold the shoes in place while you stretch the springs. Make sure you compare the finished side with the other side, and refer to your repair manual if you aren't sure how to re-assemble your brakes.
It's usually a good idea to re-pack the bearings while you have this wheel apart, but not a requirement. Once you have it all together, try slipping the drum back in place. It should go right on easily as you adjusted the brakes back to make room for the new shoes. Now take it back off, and leave this side exposed while you do the other side. After both sides are complete and you have turned or replaced the drums, go ahead and reassemble the rest. Make sure you tighten the lug nuts well, and replace any cotter pins and grease caps. Be sure to road test your breaks at a slow speed in a safe area. The first few times you stop they may not work, as you manually adjusted them to make room for the new shoes. Some vehicles adjust only when backing, so move forward and stop, then back and stop a few times until the brakes are fully adjusted.
Remember, some manufacturers recommend additional work when replacing brake shoes. See your car's repair manual for specifics, and don't be afraid to ask for help if you find yourself in over your head. If you do end up opening your lines or bleeder valves, make sure you bleed the air out of the lines and refill your hydraulic system. Be safe, and good luck.
