Proper maintenance of your car's brakes and braking system is critical for safe operation, whether it be in a race setting or just daily driving. This sounds like common sense, but you'd be amazed at how many cars and trucks are out there on the highways with brakes that need servicing and maintenance.
Since 2QuickNovas is a site that focuses on cars from the muscle car era, I'll start with a warning. Older brake pads and shoes can contain Asbestos, which made for a good friction material, but its harmful to be around and breathe. It causes a from of cancer known as Mesothelioma. So if you are dealing with a vehicle with old pads and shoes, be very careful since the parts could be old enough to contain Asbestos. An Asbestos-rated mask/respirator is one precaution and gloves would probably be a good idea too. I suggest reading up on the dangers of Asbestos and Mesothelioma and consult more expert advice on how to protect yourself. I certainly am not a doctor and don't even play one on TV. Click here for more info and links about Mesothelioma
OK, enough of that. Down to business. Work on one side of the vehicle at a time so that you can reference the other side in case you forget how it all goes together. I'll assume that you can get the car up on jackstands and the tires and wheels off. At this point, we'll need to differentiate between disc and drum brakes. Since most cars these days have disc brakes on the front and many older cars have been changed over to disc brakes, we'll start there.
Now is a good time to check the wheel bearings too. Everything should turn freely, with no feeling of roughness. If you have the style rotor with the wheel bearings pressed into them and you need to remove it, remove the dust cap (a hammer and a screwdriver is usually your friend when doing this), remove the cotter pin and castle nut. Then the rotor will pull straight off the spindle. The outer wheel bearing will want to fall out, so take care to keep it in place so that it doesn't get dirty. Dirt is the mortal enemy of a bearing. The inner bearing will be held in place by the grease seal.
If you are replacing the rotor(s), you'll want new bearings, races and seal. A long punch and a hammer will work for removing and installing it all. Just be careful to not damage the running surface of the races when driving them back in. Just work your way around the outer edge of the race until its seated fully in its bore. Then grease the bearings by placing a glob of grease in the palm of your hand and rolling the bearing through it. Do this until grease oozes out of the rollers all the way around. Then put some grease in the area between the two races, place the inner bearing in its race and install the grease seal. Be sure to keep the grease off the braking sufaces. Any grease, oil, finger prints, etc on the rotors or pads can and will hinder proper braking. So clean everything good with brake cleaner before putting it all back togehter. Once the rotor is slid back over the spindle, put the outer bearing (the smaller one usually), the washer and castle nut on. Tighten the castle nut until it is snug, but don't torque it. Back off on the nut slightly until it lines up with the pin hole in the spindle and install a new cotter pin. You shouldn't have to back off the castle nut very much at all before one of the slots in it lines up. The idea is for there not to be any "slop" in the assembly but no torque on the nut either. Clean up the dust cap, wipe off any excess grease and gently tap the dust cap back into place.
Remove the cap from the master cylinder and using a c-clamp, push the piston(s) in the calipers back. This is to allow for the new pads to have room to fit over the rotors. You will probably push some brake fluid out of the master cylinder, so be aware of that. Brake fluid will ruin paint, so watch out. Silicon brake fluid doesn't hurt paint, so its good to use in show cars and vehicles where the underhood appearance is important.
The pads go back in the calipers the same way they came out. Just keep track of how they came out and reverse the process, taking care to keep your hands off the friction material portion of the pads. Put the calipers back on their mounting bracket. There is really only one way they can go on, but some pads have grooves or tangs in the ends of them that engage the mounting brackets. So be sure they end up where they are supposed to be. Put the bolts back in and torque them sufficiently. Different vehicles have different size bolts, so refer to a repair manual for the proper torque specs.
Give the rotors a spin by hand. It should all turn freely and smoothly. If not, now is the time to find out why.
Do the same for the other side of the vehicle and if you are only replacing the front pads (which is very common to do since rear brakes don't wear nearly as fast), pump up the brakes after its all back together and finally top off the master cylinder's fluid.
Go for a test drive and gently break in the pads and rotors. Don't jam on the brakes and get them hot. Just season them in with some normal stops. Take note of any tendancy to pull to one side or vibrations and investigate as necessary. A pull to one side could be a caliper that's not floating correctly or a wheel bearings that's too tight. A vibration is often a warped rotor.
Most front drums come off like front discs, but some will just slide off the hubs. Rear drums just slide off the axles. Once the drums are off, look at the running surfaces of the shoes and the drums and see what you have. Hopefully the shoes have not worn enough to let the rivets gouge the drums. If they have, new drums are the likely result. For the most part, you're looking for the same type of wear and damage as you would on a set of rotors. The drums are also marked with a maximum inner diameter, so make note of that when deciding if you can reuse or turn the drums. Any grooving, gouging or wear that requires a drum to be turned larger that is max. recommended inner diameter should be replaced with new or a suitable used drum. You may find the front and rear shoes are not worn quite evenly. This is fairly normal and not a big cause of concern.
There are special tools that you can buy/rent to remove the various springs involved with drum brakes, but I've always been able to use various pliers and screwdrivers to get the job done. Start by finding some safety glasses. Nothing will ruin your day of wrenching quicker than a big spring sticking in your eye! These are pretty stout springs, so they can do damage. Anyway, where was I? OK, I remember...start by taking a mental (or actual) picture of the assembly with the drum removed to familiarize yourself with how it all goes together. Like I said before, only work on one side at a time so that you have something to look at in case you forget. Then remove the springs in the top middle that pull the shoes inward against the wheel cylinder. A long, flat screwdriver and a large set of pliers will work for this. A little pulling and prying and you'll have them off in no time. Once you've done this, you can remove the little springs and retainers that hold the shoes in place. Using a large set of pliers, grip the round retainer, press inward and twist to release. You may have to push with your hand on head of the retainer pin that passes through the backing plate in order to keep it from moving back when you compress the spring. You'll see what I'm talking about when you get in there to do it. The shoes will now be free, except there will be one spring at the bottom tying them together. Just slip it out of its grooves and you'll have it all torn down. Note which side the bigger shoe came off of.
Inspect the backing plate for wear in the areas where the shoes rub against it. Also look for signs of leaks from both ends of the wheel cylinder. If you see any leaks, now is the time to replace it. They don't cost much and the amount of work to replace them at this point will be minimal. They are held on by a couple small bolts that go in from the back side of the backing plates and of course the brake line screws into them as well. The final piece to inspect is the adjuster. Be sure the star portion isn't excessively worn and that everything is free turning.
Now its time to start putting it back together. At this point you should have your new shoes, new or turned drums (if necessary) and you might as well use a new hardware kit. The kit is cheap and comes with all the little parts and springs. Hose down the backing plates with brake cleaner to clean up the excess dust and grit. Then apply a light coating of grease to all the points that the shoes contact on the backing plates. Like always, don't get grease on the friction surfaces of the shoes or drums. If you do, clean it up with brake cleaner. Attach the shoes to the backing plates using the little pins, springs and retainers, putting the big shoe on the side it suppose to be on (now there's a revelation! LOL). Be sure the plungers on the wheel cylinders are engaging the shoes properly. Usually there's a square slot for this. Continue the reassembly by installing adjuster and the spring that ties the shoes together at the bottom. Now you can reinstall the springs on the upper portion of the shoes. It'll take some pulling and prying, so be careful.
Everything should be put back together at this point. So walk around to the other side and compare what you have. If everything is in the right place, give the pads a shot of brake cleaner, as well as the inside of the drums. Slide the drums back on and give it all a turn. You may have to back off on the adjusters to get the drums on. Then adjust the shoes out until they just barely contact the drums. Everything should still turn freely, but you'll hear just a slight dragging of the shoes on the drums.
If the brake lines were loosened or removed at any time, you'll have to bleed the brakes. Start at the right rear, then the left rear, then the right front and finally the front left (as viewed from the driver's seat). Using Speed Bleeders makes this a one person job or you can do it with the stock bleeders if you get a buddy to help. I've also done it alone by rigger up a pole to wedge between the bottom of the steering wheel and the brake pedal. Basically you pump up the brakes, hold pressure on them, crack open the bleeder, tighten the bleeder and pump up the brakes again. Keep doing this at each wheel until you get fluid that is free of bubbles. Make sure to keep an eye on the master cylinder level. If you pump it dry, you'll fill your lines with air and make it a lot more trouble to bleed. With Speed Bleeders (available from sources like Jegs, Summit, Northern Auto Parts, etc), you loosen it and then pump. They have an internal check valve that prevents air from being sucked in. A piece of hose on the nipple of the bleeder, running down into a cup will contain the mess. If its a clean cup, you can even reuse the fluid.
As with discs, go for a slow test drive to be sure its all working properly with no pulling or grabbing. Make normal stops to season the shoes before doing any spirited driving. If anything seems amiss, take the time to find out why. Going fast is fun, but stopping is what gets you home at night!
Copyright © 2008 Bruce Johnson and Craig Watson