Solving Brake Problems
There are several different configurations of drum brakes, but they all work similarly. The wheel cylinder forces the shoes against the inside of the brake drum and the brakes are activated. When you release the pressure in the wheel cylinder, the return springs pull the shoes away from the inside of the drum so that the brakes don’t continue to make contact. When replacing brake shoes, these return springs probably cause the most problems. I can’t stress enough how having the correct tools for this can save your bacon. So before you get into a rear brake job, I suggest you pick up a set of tools for servicing rear shoes. Trust me; you’ll thank me later. They really aren’t that expensive and I know you like tools. Why else are you reading this?
Aside from the right tools, you’ll need the right lubricants. In this case, anti-seize is your friend. This is my preferred lubricant for the bosses on the backing plate where the shoes ride.
Speaking of this backing plate, inspect it carefully when doing your shoe replacement. You will see groves in these bosses, but sometimes they get too deep or wear right through the backing plate. If this happens, you have two options: Replace the backing plate, or weld them back up and grind them down. Either way works; just don’t ignore it.
One thing you might notice if you have a problem like this is a pop from the rear brakes during application or backing up. This pop is caused by the brake shoes hanging up in these groves. Lubricate or repair these bosses and the noise should go away.
In addition to the backing plate, you also need to get the brake adjustment correct for best results. Whenever you install brake shoes, you need to reset the self adjuster so that your shoes make good contact with the inside of the drum again.
This process can take some time and practice, but if you do it right, you’ll have a brake pedal that feels as solid as a rock. When you have a vehicle with drum brakes, your brake pedal feel is dictated by this adjustment. Sometimes people come to me thinking they need brakes, and all I need to do is clean and adjust the rear brakes and they think I’ve replaced the entire brake system. Take the time when you’re done replacing the shoes to adjust the brakes properly. Not only will your brakes feel better, but your parking brake will work better too. Don’t go too tight, however; if you do, the brakes might drag and overheat, causing other problems. It takes a bit of practice to get a brake adjustment right. Better to go too loose than too tight.
If you’re replacing your brake shoes, you should also consider replacing the springs and hardware. These often come in a kit called a hardware kit, and are usually fairly inexpensive. Considering these springs help the brake shoes return after a brake application, it’s a good idea to replace them when doing drum brake service. Just ask for a hardware kit when purchasing your brake shoes.
Here are a few videos about replacing brake shoes that you might find helpful.
Some people think that if you have one bad wheel cylinder, you should replace them both. While this isn’t a bad idea, it’s not necessary. You can just replace one wheel cylinder if it’s leaking. Another common misconception is that you need to remove the brake shoes to replace a wheel cylinder. This is not true; in fact, I don’t recommend you do. You can often crank out the self adjuster to spread the shoes away from the wheel cylinder to gain access to it.
Another note on wheel cylinders: If you find that the brake line going into it is rusted, stop trying to turn it; you could damage the brake line. Instead, dismount the wheel cylinder from the backing plate and spin the wheel cylinder off of the brake line. This way, you avoid damage to the brake line, thus saving yourself a bunch of time and money.
Diagnosing a bad wheel cylinder is fairly simple. After you remove the brake drum, pull back the dust boots on the wheel cylinder and look for fluid. If you see fluid coming out, replace the wheel cylinder. You can rebuild wheel cylinders, but as with rebuilding brake calipers, you might end up with more trouble than it’s worth. Only rebuild wheel cylinders if you can’t find the parts you need or the parts are too expensive. In my experience, wheel cylinders aren’t all that expensive. Here’s a video on replacing a wheel cylinder you might find helpful.
You might find that your parking brake is not working like it should. This could be due to several things. The first thing I often check is the rear brake adjustment. Viewers often ask how to adjust their parking brake cable. I always tell them to adjust the rear brakes first, then see if they still need more adjustment for the parking brake. If you get the rear brakes adjusted and still don’t have enough tension on the parking brake, then adjust the parking brake cable or adjuster, not before. If you adjust the cable without addressing the rear brakes, you might have issues installing the brake drum after a brake job because there’s too much tension on the cable. If you have a parking brake problem, adjust the rear brakes first, then the parking brake cable.
In addition to adjustments, things can break. Mostly what I see is broken cables. This is what to look for if your parking brake suddenly stops working. Keep in mind you might have to remove some exhaust shielding in order to access the cables.
If your parking brake assembly is inside of the rear rotors, the adjustment is often accessed through the front of the rotor. Don’t adjust these too tightly. If you do, you can overheat the brakes and cause other problems.