Brake Caliper Rebuild - Do It Yourself and Save $$$

[PearlWhiteMR2]

Recently at school I learned how to rebuild brake calipers, it's very easy to do, although it can be time consuming if you run into problems, but overall the money saved makes it worthwhile to do yourself. If you don't think this is something you can do, or don't have the time/tools, I can do it for you for a bit extra for my time. I will have to bring them in to school and get them back to you later. It will still be much cheaper than buying them!

What you will need:

1. Brake caliper from your car (including bracket, but take the slider bolts out and separate the two pieces)
2. Brake caliper rebuild kit ($65.00 from Sunrise Toyota with our BCMR2 discount, beware you probably have to order them from the East or elsewhere so it may be a 2-6 day wait)
3. Air compressor/blowgun
4. 2x4 piece of wood, about a 6-12" piece
5. Shop rags
6. Brake fluid or brake assembly fluid
7. Clamp or vise to hold caliper while you remove parts (optional, but highly recommended)
8. Brake slider grease (the rebuild kit comes with some, however it is not very much)

How to do it:

1. To begin, take the slider bolts out of the bracket that supports the pads and the caliper floats on. Put them aside, and don't worry about mixing them up, they only go in one side each. Remove the brake line bolt and drain the remaining fluid from the caliper, if you haven't already

2. Place this aside, take the caliper itself and mount it in a bench vise or other holding device. You want the open side facing up towards you, the piston(s) should be perpendicular and facing away from you.

3. Place the 2x4 piece of wood along the backside of the caliper bracket, opposite the pistons. This is where the pad would rest that was -not- touching the pistons. The pistons should have nothing blocking them directly. This wood stops the pistons from shooting out and bouncing off the bracket and hurting somebody.

4. Place the blowgun's rubber tip securely into the brake fluid line hole, and apply NO MORE than 30PSI of pressure. It shouldn't take more than a very light squeeze on the trigger before the pistons pop out and hit the wood. Be warned, this can be loud and may make you jump! (Note: If the pistons are seized, as mine were recently, you may have to apply extra air pressure and a prying force to get them out. Be very, very careful if you do this as the pistons may come out very fast and hard! Mine came out slowly because they were so seized, but just in case, exercise caution!)

5. Remove the wood and pull the pistons out by hand. Remove the old dust boot and note the position it went on for re-installation.

6. Using a flathead screwdriver, insert it -gently- into the piston bore and pry out the old square-cut seal. Discard it. Do not scratch the bore with the screwdriver!

7. Clean the bore and the piston if there are any deposits or rust on them using solvent. Do not score the bore by using abrasive cleaning techniques. A gentle towel or rag will do the trick. If the seats for the seals and boots have deposits and rust in them, you can tidy them up with a bit of medium grit sandpaper. Be sure to clean the bores out thoroughly after, don't leave any dust or dirt behind.

8. Clean the piston with a bit of oil or brake fluid and very fine sandpaper, only if there are deposits on them. If not, simply wipe them with a gentle rag and solvent, and dry.

9. Once all parts are clean and dry, install the new square cut seal. This will be the square-cut black ring in the rebuild kit. Make sure to press it in firmly to it's seat, on all sides, and feel free to use a bit of brake fluid to help it slip in easier.

10. Lubricate the bore well with brake fluid. Put the dust boot onto the piston, ensuring it is on the correct way. Place the piston straight into the bore, and push it down slowly, making sure it stays straight. Push it down almost all the way, but not quite to the bottom. You want to leave some room for brake fluid, and also you will be adjusting them for the pads and rotor later anyway.

11. If you have more than one piston, do the same for both, making sure they are both of equal height when pressed in.

12. The rebuild kit should have come with dust boots for the slider bolts as well. On the pad bracket, take the old ones off. They may be really stuck due to years of being on there, so you may have to chisel them off. Clean the mating surfaces well after you get them off.

13. Clean the slider pins and the inside of the slider pin bore as well as you can, ensuring both are dry and debris-free before re-installation.

14. Put the new dust boots on, you may need to gently hammer them into place using a soft rubber mallet or other similar technique. Press the rubber boots down flat after the metal base is installed and squirt some brake slider grease into the hole, about three peas worth.

15. Put a medium-thickness layer of grease on the slider pins and install them into the bores. Ensure they can go all the way in and squash the dust boots down, and slide out fairly easily with some resistance. Don't worry too much about extra grease, it will squeeze out the top. Just clean up the bolts and dust boots afterwards.

16. Put the pads in their clips and bolt the bracket onto the caliper itself, ensuring the dust boots on the slider pins are not twisted, and both sliders sit evenly.

17. Install the new copper washers that come with the rebuild kit onto the brake line bolt.

18. When re-installing the caliper on the vehicle, make sure there is a washer on each side of the line to prevent leaks.

19. Once the caliper brake line is attached to the car, mount the caliper and continue with normal bleeding procedures.

And that's all there is to it! Once you've done it once or twice, the procedure becomes easy, and doing all the calipers yourself can save you a lot of money. If you have any questions, please don't hesitate to ask me!

[Saiko]

Thanks for the write up, Sarah! For the rebuild kit, is that the entire kit for all four calipers?

What are some signs that I should look at to see if I need to rebuild mine? (reaching 237k kms soon and has sat for quite a bit in the last few years).

[PearlWhiteMR2]

Well look at the rubber boots on the slider pins and check their condition. Move the caliper back and forth on the sliders, and the caliper should move on them. If they are seized they won't move at all. Check the dust boots on the pistons themselves as well, you'll have to remove the pads to do so, though. If they are quite dry and brittle, if you see any rust or water that appears to be coming from a crack in them, they need to be replaced as soon as possible. If you've noticed your brakes grabbing or suspect they are goingto seize, or if they've never been rebuilt or replaced, then you'll need to do it. The price is for front calipers only I don't know what the rears would cost. Hope that helps!

[sbarc]

A very good write up Sarah....I am VERY impressed. :BowDown

If I may add some further points that might help.....

Regarding the cups......if they are rusted and this corrosion will rub against the rubber seals, then it is a good idea to replace the cups. Any sort of roughness will score the new rubber seals and shorten the live of the caliper.

Plus you always have the option of painting the calipers in some attractive colour....IIRC there are special heat resistant paints available for this.

Also....for those without an air compressor.....you can pop the cups by simply unbolting the caliper (while leaving the brake line connected)....pressing the brake pedal until the cup is almost out.

To avoid all the brake fluid dripping out of the line and getting air in the system......you can pinch the rubber brake line with smooth vise grips.....before you disconnect the brake line from the caliper. Make sure you don't damage the rubber brake line with the vise grips.

[immorality]

To avoid all the brake fluid dripping out of the line and getting air in the system......you can pinch the rubber brake line with smooth vise grips.....before you disconnect the brake line from the caliper. Make sure you don't damage the rubber brake line with the vise grips.

I used to have a set of these:

[PearlWhiteMR2]

Thanks!

If by cups you mean pistons, then yes you could replace them but I had rust in mine from a leaking boot and the pistons were fine. They are made of a high quality steel. I used a bit of ATF and a very fine sandpaper to sand the debris off but underneath they were shiny and new. As long as you don't score them at all, they probably will not need replacing. Mine are 20 years old with 350000kms on them, and if they were fine, yours may be too!

As far as removing them with the brake pressure itself, I don't recommend this, at least not if you don't have a friend to help you. You need to ensure the pistons don't shoot out all the way because they can hit things, become damaged, etc... Something like a piece of wood has to be there to stop them and unless you have it taped or held onto the caliper in some way, this may not work. It's a good idea, though, because yes, not everybody has access to compressed air!

[sbarc]

As far as removing them with the brake pressure itself, I don't recommend this, at least not if you don't have a friend to help you. You need to ensure the pistons don't shoot out all the way because they can hit things, become damaged, etc... Something like a piece of wood has to be there to stop them and unless you have it taped or held onto the caliper in some way, this may not work. It's a good idea, though, because yes, not everybody has access to compressed air!

Actually it's works quite well with pedal pressure....you just need to apply the brakes slowly and ease the piston out far enough so it is almost out and easily to be removed by hand. I've done this many times without any problems. If you're doing it by yourself as I did then you merely push the pedal a bit and check the piston etc until it is where you want it. And yes...this methiod works with seezed pistons as well. Agreed....it's not the best way to do it....but plenty of folks don't have a compressor and bench vise etc and this method gives the same results.

One thing I will suggest while we're on the topic of brakes.......

When replacing brake pads....don't push the dirty brake fluid in the caliper back into the system. the brake fluid in the caliper is usually quite dirty.

So....have a C-Clamp......hose that fits the bleder nipple on the caliper and a container to collect the old fluid.

Remove lower mounting bolt from Caliper.
Swing caliper up.
Remove old brake pads
Attach hose to bleeder nipple and stick other end into fluid container.
Attach C-Clamp to push the piston back into the caliper......but don't use the c-clamp to push the piston back yet.
Open bleeder nipple slightly
Use C-Clamp to push piston back into caliper making sure old dirty fluid comes out of the bleeder nipple and goes down the hose into your container.
Close bleeder nipple.
Install new pads and reinstall caliper
Push brake pedal to firm it up and connect pads with rotors.
Fill up brake reservoir.

If your brake reservoir is low then you might want to top it up a bit before beginning this job.

This process will remove the dirty fluid from the caliper and keep your brake system cleaner.

[PearlWhiteMR2]

Good tips, thanks!

I guess I just figured it wasn't a good idea to do that because I've seen how fast those pistons come out and the bang they make when you use just 30PSI of compressed air. I suppose if you are very careful, the pedal method works fine too.

[Solo_D33A]

What school you go to? I'm at BCIT AST 1st term and I've just finished up on rebuilding them and into drum brakes just last wed.

[PearlWhiteMR2]

I am in Kwantlen, we are wrapping up engines and moving into engine management. We finished brakes in January but I just rebuilt my own caliper because it needed it. Nice timing, too.