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Drum Brake Cylinder Replacement
Time: 2016-11-28
It does not matter how well your car starts or moves if you can't stop brakes. That’s why it is very important to check your brakes regularly. There is never a good time to ignore brake repairs.
If you know you need to replace one of your drum brake cylinders, you may try to do it yourself. Proper and thorough testing after a brake repair is essential to your safety. But once you've tested the system, chances are you did the repair correctly and your vehicle is safe.
Before you can even see the brake cylinder, you'll need to remove the brake drum. It comes off fairly easily with one bolt in the center holding it on. Be sure your emergency brake is not pulled up for this job (but use some wheel chocks to keep your car from shifting while you have it on the jack stands safely). With the brake drum off, you will be able to see the brake shoes and the wheel cylinder that requires replacement. Unfortunately the brake cylinder (also called the wheel cylinder) is guarded closely by two brake shoes and a cluster of springs. This mass can be very intimidating. The good news is on most cars this cluster of shoes and springs can be removed as a single unit without taking it completely apart.
Brake drum removed, you can see the brake shoes assembly with lots of springs, and the wheel cylinder at the top.
There are two pins that hold the brake shoes onto the backing plate. These are spring loaded from the front, so the best way to remove them is to push them in from the front, and then reach around to the back and give them a twist. Twist each pin a quarter turn and that cluster of brake shoes and springs is almost out. The brake cylinder at the top is the last thing attaching the shoes assembly to the backing plate.
Using a large spreader, or two screwdrivers, pry the top of the shoes assembly apart enough to clear the wheel cylinder ends, and you'll be able to see the wheel cylinder clearly. If you were lucky enough to keep the brake shoes assembly in one piece, set it aside for reinstallation later.
You need to disconnect the brake line before you start to remove the bolts on the back of the wheel cylinder. The brake line is threaded into the back of the wheel cylinder through the large backing plate. To remove it, find the correctly sized line wrench to loosen then unscrew it. It is recommended that use a line wrench to avoid stripping the hex on the brake line. Once this is ruined the whole line must be replaced. A regular open end wrench doesn't have enough surface area on the hex head to remove a stubborn brake line.
With the brake line removed you are finally read to remove the wheel cylinder. It will be held in place by one or two bolts through the back of the brake backing plate. Many original steel or iron wheel cylinders are held in place by two bolts, but the replacement part may be held in by a single bolt. This is normal, and if your new wheel cylinder has only one bolt, there should be a note in the box telling you it is normal. Remove the bolts on the back of the wheel cylinder, then pull the old one off.
As they say in car repair, installation is the reverse of removal, so get to it. And don't forget to bleed the brakes when you are done.
Source: About Autos