Brake Caliper Rebuild

btw, never again will I buy a Haynes manuel.

Ernie,

I repaired a bad piston seal in one of my front calipers in my little Mazda commuter and it wasn"t difficult at all. I don"t know how much of this will translate to the job you"re about to do, but here"s what I had to do:

- Remove tire
- Remove caliper retaining bolts/slides
- Remove brake line and plug as best you can to avoid excessive leakage of fluid
- Pull the whole caliper off
- Use compressed air (I used a 50cc irrigating syringe) to force the piston out of the caliper bore-- apply pressure where the brake line goes into the caliper and be very careful not to drop the piston (do this an inch or so over a nice soft, clean mat
- Clean out the cylinder bore and look for scoring, cracks, scratches, etc.
- Carefully replace the seal and boot and push the piston back into the bore after you wet the seal and the bore with fresh brake fluid
- Once it"s seated, use a c-clamp to carefully drive the piston back to where you need it
- Reinstall pads, caliper, brake line, mounting bolts, etc.
-Bleed lines well-- you may have gotten a good bit of air in there, so be careful

Voila! that oughta do it. You probably oughta find a good manual on your vehicle that tells you if this is the correct procedure for your van or not. In my case, the seal and boot only cost about $5 total and the repair was trivial. It"s still working great with no leaks, even pad wear, and good braking force a year later.

Best of luck,
Darren

The brakes were ready for new pads and rotors when I had new tires mounted by a garage. Curious thang was after the garage mounted the tires I noticed the caliper boot tore. The garage also promotes brake rebuilds. I have no way of proving they did it, maybe it was a cosmic ray.

So in the 110,867 mi we have had the car, the pads have wore evenly, there is a sealed oil reservoir boot that lubes the caliper locking bolts.

I have had the brake fluid flushed pre-emptively at 80k miles, as well as some of the lines replaced as there were pretty rusty.

I was looking to substitute the seal on the van without having to break the hydraulic seal or bleed the brakes.

You may be able to replace just the boot but if it is bad you just as soon do the whole job. The o-ring is just as old.

You MUST have compressed air and a good C clamp. If you do not; stop here cause you can not do it.

Take the caliber off the truck. Put a block of wood where the rotor and pads would be to prevent the piston from flying out and shoot air into the hole where the brake line goes to push out on the piston. Adjust the size of the wood smaller and smaller till the piston come out. Once you see the o-ring on the piston you can usually pull it out by hand.
When you get the piston out you will see it has a boot at the top and a o-ring about half way down. Replace both with new parts. Check to see if the caliber hole has any pitting and sand the glaze off with fine sandpaper. Clean it up and coat ever thing with brake fluid. Now reinstall the piston using the c-clamp and a piece of wood so you can apply equal pressure to the entire piston and push it straight in. Watch that the o-ring does not roll as you start it. Push it all the way to the bottom of hole. Reinstall on truck; bleed brakes and you are done.

Note... If you ever have a caliber that is binding and will not release the brakes on its own. It needs to be replaced as it is not rebuild able.

Now remember the book does not tell you how to do it for a reason. I am not there to make sure you do it correctly so you are on your own now.