The front brakes on my car are shot, and have been on long after they should have been replaced. I have a very good idea about how to replace them, having seen it done numerous times before. I was giving some serious thought to doing it myself.
I have a few questions before I do anything, though:
Since this would be my first time doing this, is there anything I should know before I go at it? Will I likely encounter any potentially catastrophic surprises?
Is this more difficult than I think it is, and should I leave it to someone who has done it before?
Before you take anything apart, use a digital camera to photograph your caliper and discs from several angles.
Get some Brakleen spray and clean 'em off real good before taking the pictures.
Disc brakes are usually so simple that anyone with the slightest bit of mechanical inclination should be able to change them. But there are often anti-rattle clips and springs that have to be put back on just right or you’ll have noisy brakes. That’s when the photos come in handy.
If you get confused about how they go back together, you can always reference the photos and see how they were before. Also, those anti-rattle clips are often spring-loaded and when you try to take them off, they go flying away.
When you buy your new pads, ask if there’s a hardware kit available. They’re usually only a few dollars.
Also, price new brake rotors…sometimes they’re cheaper to buy new then they are to get them resurfaced. And if they’re scored really deep, you might not be able to get them resurfaced.
Disk brakes are easy if you’re good with hand tools. On a Chevy you’ll probably need a 13mm (I think) allen wrench, a socket set , and maybe a C-clamp to compress the calipers a bit.
I would recommend a Chiltons or Haynes repair manual (~$15.00).
Haynes has the best pictures of repair procedures, but both are pretty clear about what you need to do.
You need someone like GaryT to come along with specific info. I’m the veteran of self-taught brake jobs on perhaps a dozen different car models. I’ve had good success and never run into anything catastrophic. I’m sure there are exceptions, but brakes tend to be reasonably simple and logical.
One small warning would be to avoid asking the brake lines to support the weight of calipers that you have removed. Have a coathanger handy and fashion a supporting hook from this.
Disassemble one side at a time. Wear a face mask. Brake dust is not healthy for your lungs.
Lots of people also wear latex gloves to make clean up easier.
Check you master cylinder fluid level before you start. It is at or near full, use a basting bulb to remove some brake fluid before starting work.
In any event, cover the cap to the master cylinder with a rag before starting work.
Loosen the the lug nuts BEFORE you jack the car up.
Jack up both sides of the car, and take off both wheels, so you can go to the other side and make damn sure you are doing it correctly.
Use jackstands. If you don’t own jackstands, and are not willing to buy some, stop right now, and take your car to a pro.
Do not even think of just leaving the car supported on a jack only.
After placing the car on a jackstand, before you get down to work on it, grab the fender and push, shove, wiggle, and body check it for all you are worth. If it is going to fall off the jackstand, now is when you want it to happen.
Did I mention use jackstands?
Read a Chilton’s manual. If there is a torque spec for a bolt, use a torque wrench.
Buy good pads. Ditto for rotors.
Follow the instructions for compressing the pistons (some rear calipers have to be screwed back in, other don’t)
Clean the new rotors off with brake clean and a clean rag before installing.
Use a small hand held wire brush to clean all the gunk off of the various nooks and crannies of the caliper.
If your car has sliding calipers, use the correct lube for the sliding parts. Do not use just any old grease.
Do not allow the calipers to hang from their hoses. Get a metal coat hanger and fashion a hook.
Snug the lug nuts before lowering the car.
Torque the lug bolts when the car is back on the ground. VERY IMPORTANT!
When you are all done, Do the following:
[ol]
[li]Start the car[/li][li]Do not shift out of park[/li][li]Slowly pump the brake pedal, until a normal pedal is felt. (1-2 seconds per stroke)[/li][li]Now you can shift out of park[/li][/ol]
Do not do step 4 before step 3, or you may find this is the most expensive brake job ever.
Did you remember to torque the lug nuts?
In simple layman’s terms, fuck it up and you could die. Or you could kill someone else, like the kid in the crosswalk.
Brakes are not hard, but they carry a large responsibility.
I have found that plastic zip ties (tie wraps, whatever - these things) are great for supporting the caliper once you’ve got it off. You can daisy-chain them together to make a loop of arbitrary length that’s easy to shorten. To release, simply cut 'em apart.
I’ve tried several methods, and have found this one the easiest. The calipers on my Mazda pickup truck are pretty heavy (two pistons), and I’m not sure a bent coat hanger can be trusted to hold them.
Step 5: Take the car on a slow test drive at a time where if something goes wrong, you’ll be unlikely to kill anyone. Make sure you step on the brake pedal frequently.
Step 6: When you get back home, check the fluid level in the brake master cylinder. If it’s low, top it up, and then recheck the wheels for leaks, you may have not gotten something tight enough, or you might have had a brake line/seal crack on you, thus allowing the fluid to leak out.
Depending upon the type of brakes you have and the amount of work you have to do to get them repaired, you might want to invest in what’s known as a “One Man Brake Bleeder” this will allow you to get any air out of the brake lines that might have crept in (air in the brake lines is a bad thing). Otherwise, you’ll have to have someone in the car pumping the brakes while you crack the bleed valve on the calipers to get the air out of them.
I also second the recommendation to buy good pads. I bought the el cheapo[sup]TM[/sup] brand the last time I did mine and now, depending upon the weather, they can squeal like the devil.
On non-ABS cars, the caliper pistons are pushed back into the caliper (necessary to make room for new, thicker pads) and the fluid is correspondingly pushed back into the master cylinder. Hence Rick’s suggestion to make sure there’s room in the master cylinder’s fluid reservoir. However, on ABS cars, it is recommended NOT to do this, to avoid any chance of debris in the fluid fouling a tiny port in an expensive ABS part. The proper procedure is to have the caliper bleeder screw open (put a hose on the bleeder nipple, going to a container to avoid a huge mess) while pressing the piston back in. This also makes it much easier to move the piston. You can do it the other way, and there’s only a small chance of a problem, but if there is a problem it could be very expensive to fix.
To minimize the chance of annoying brake noise, get premium-grade pads (specified as quiet), and - whatever pads you use - apply the proper stuff on the metal back of each pad where it contacts the piston or caliper body. What is proper will vary with the particular pads, but is typically nothing (some premium pads), high-temp grease (most good quality pads), or a special goo (most economy pads). Also, apply high-temp grease to any place where the edge of the pad’s metal back touches/slides on anything. DO NOT GET ANY SUBSTANCE ON THE ACTUAL FRICTION SURFACE OF THE PADS OR ROTORS.
Make sure the caliper bolts/pins/slides move in and out fairly easily. If they’re a little stiff, some high-temp grease may help. If they’re really stiff, you’ll probably need new pins and bushings, and to clean out the holes in the caliper that the bushings rest in.
Make sure the new rotors are clean of any protective film. Make sure the surface of the hub that the rotors go against is clean of debris so that the rotors will fit squarely.
Have a piece of wire (about 1.5-2 feet long) near by. Once the caliper is off, you can’t let it hang by the brake line, that’s bad. So until you can get the old pads off, the new ones on and the whole thing back in place, you have to be holding it in your hand. If you need to rest your hand, do something with both hands, go and get another tool etc… you can use the wire to hang it from the car. Sometimes, you can kinda prop it up on something, but it’s just easier to have a piece of wire nearby.
Generally, you can expect a little more squeaking if you are just replacing the pads and not doing anything to the rotors. The pads should seat well and quiet down, but there is a chance they won’t quiet down, even though working perfectly. “My brakes are squeaky” is an all-too-common complaint. It’s not a big deal, but many people think they should never squeak, because their father, grandfather, or half drunk old mechanic told them.
Yes, disc brakes have an inherent tendency to make “annoyance noises,” usually squeaks. With lesser quality pads, replacing or resurfacing the rotors is one of the several things to do to minimize the chance of such noise. Properly lubricating the contact points where the edge of the pad’s metal backing touches any channels, clips, etc. is another. Applying the proper grease (CRC Synthetic Brake and Caliper Grease is one brand) or goo (one brand is Disc Brake Quiet) between the pads and piston or caliper body is another. And in some applications, pad-backing shims are available which also help. Perhaps the single most effective thing is to use premium-grade “quiet” pads. I use Wagner Thermo-Quiet and find that rotor resurfacing/replacement is not necessary for noise reduction. I also always grease the edge contact points, and apply grease or goo when indicated to the pad backing. I don’t remember the last time I had a noise issue with a brake job I did.
That must be a brand specific recommendations or one for 'merican cars. Or maybe just compressing the pistons is only done on Volvos with ABS. But the factory repair procedures on a Volvo with ABS have you just compressing the pads. No opening of the bleed screw is required.