How to Replace Wheel Cylinder
Replacing a wheel cylinder on a vehicle with a standard non floating axle is a relatively easy procedure for the do-it-yourself individual. It does not take much time and does not require a bunch of expensive tools. It requires a jack, jack stands, wheel scotches, lug wrench, torque wrench or socket and ratchet to fit the wheel cylinder bolts, a straight screwdriver set, hammer, soft face hammer, chisel set, brake shoe adjuster tool, and a flare-nut wrench. I also recommend you get a good lubricant like liquid wrench, PB, or WD40, as the bolts and the line are exposed to the elements and often become rusted and seized. It is also recommended that you wear latex gloves, a face mask, and goggles when working on brakes because the dust can be toxic. Some brake shoes are made of asbestos which is known to cause cancer. The procedure should be done on a level and firm surface. The ideal location would be a garage, but many of us are not fortunate enough to have this luxury.
The first thing that should be done is to scotch the wheels so the vehicle can not roll. Always take every precaution you can to prevent damage to your vehicle and injury to yourself and it is also a good idea to get into the habit of double checking your work. Once the vehicle is adequately scotched, you then need to take a lug wrench and just loosen the lug nuts on the wheel. If you wait till you jack the vehicle up, you will probably find that the wheel tries to free spin when you try to loosen the lug nuts. You are now ready to jack the rear of the vehicle up and put it on jack stands. This is another safety precaution worth its weight in gold. If the jack was to fall it could cause serious injury you or damage the vehicle. Lower the jack so that the vehicle is resting on the jack stands.
Now that you have the vehicle on jack stands, you can finish loosening the lug nuts and remove the wheel. At this point, I would take the time to spray the bolts and the brake line on the backside of the wheel cylinder at the backing plate. It also helps to lightly tap the bolts with a wrench for a few seconds because the vibration helps the lubricant break them loose. I suggest this now because that will give them time to soak. As I stated before the bolts and lines are exposed to the element and have a tendency to seize up. It will make the job much easier. I would also spray them again when you go to loosen them.
Next you will remove the brake drum. You can try to pull the drum off. If it does not come off it will be necessary to retract the brake shoes. Also some vehicles have screws on the front of the drums. If it does you will probably have to get a impact driver to remove them. You will find a small oblong hole either in the front of the drum or on the backing plate near the bottom. It may be open or it may have a rubber or metal plug in it. If it has a metal plug you will have to take a hammer and chisel and knock it out. The plastic plug can just be pulled out with pliers. Inside the hole are a lever and a star shaped wheel. You will need to take a thin screwdriver and push the lever aside and take the brake shoe adjuster tool or another screwdriver to turn the star wheel several turns till the drum loosens. If by chance is still does not come off then it may be necessary to tap around the inner edge of the drum with a soft face hammer.
Most manuals tell you to remove the brake shoes at this point, this should not be necessary. My next step would be to spray the bolts and brake lines again and then remove the brake line from the wheel cylinder with the flare-nut wrench. These nuts are made of soft material and are easily deformed. That is why I recommend you use a flare-nut wrench. They make more contact with the nut surface. Next plug the brake line so all the brake fluid does not leak out. Then remove the bolts from the wheel cylinder with a wrench or ratchet and socket, if equipped. Some models just have a retainer. If this is the case you need to take a couple of screwdrivers and pry the retainer off. At this point, you should be able to take your hand and spread the brake shoes enough to remove the wheel cylinder.
Put the new wheel cylinder in the exact way the old one came out. Reinstall the brake line finger tight. Next reinstall the mount bolts and torque to specs, as this will prevent over tightening as well as under tightening. Either can cause serious problems. After that you need to tighten the brake line with the flare-nut wrench. Tighten it as tight as you can without deforming the nut. Push the shoes back together and install the drum. Reinstall the rubber plug if the adjuster hole was equipped with one. Now would be the best time to bleed the brakes. To do this you will either need a helper or you will need a one man bleeder kit. Reinstall the wheel. Finger tighten all lug nuts. Raise the vehicle enough to remove the jack stands. Lower the vehicle to where the tires touch the ground and will not turn. Torque the lug nuts to specs. Lower the vehicle all the way and remove the jack and scotches.You will probably need to adjust the shoes. This is a very easy procedure. All you have to do is start the vehicle and put it in reverse and slightly press the brake pedal. They will adjust as you back up.
