J4SON

I posted this question about a week ago:

At the end of a test and tune track day yesterday my brake pads wore down to the backing plates. It was my first time on R-comps and the pads wore MUCH more than I thought they would. Rotors look a little cooked, but I'm sure I could fix them by resurfacing them. The dust boot on the outside of one caliper completely disintegrated. This is the boot that covers the part that makes the entire caliper move. Also, it seems like the brake pistons are siezed. I couldn't move them at all, had to tow the car home. Any suggestions? I'm going to try to open the bleed valve this weekend then try to retract the pistons. Does this mean I should rebuild my calipers at all? Any way I can replace that dust boot?

Jeff Doyle had a part number for a seal kit, 4A0 698 471, but he doesn't know exactly what it contains. Anyone else know? PaJohn also suggested it would probably be easier to just get some used calipers, but I want to see if this can be repaired first. Anyone have experience fixing this? Thanks in advance.

TRM

i'd like to help but i'm no brake expert.

i would think it be best to at minimum replace and rebuild the calipers so you have working rubber covers. they obviously keep dirt and contaminants out of the piston, thus keeping it from seizing, etc.

J4SON

The only thing I could find was what Jeff posted, part number 4A0 698 471. Its titled "seal kit", I'm not sure exactly what it contains. Maybe I'll call a parts department and they can tell me.

Nick Gustas

The rear kit comes with a new dust boot and piston seal for each side. I had to pull the piston out completly to fit the new dust boot.

J4SON

Now all I need to do is find a good service manual.

O.W. Kenobi

It was because I pushed the lower piston in too far, and the upper piston "popped" out into a frozen, extended position. We had to remove the caliper, get an old brake pad to cover the frozen piston, and then use a C clamp to force the piston back in. It again "popped" and moved normally after that. Remounted the caliper and it worked fine.

Sharon

<center><img src="http://pictureposter.audiworld.com/757/meltedpiston.jpg"></center><p>I melted a piston once, so the least of my concerns was that I'd torn all the dust boots too. I had upgraded the brakes shortly after this, so never bothered to repair/replace the stock components.

You should indeed be able to get a rebuild kit, which is probably just the seals and maybe some o-rings or something. Unless you've damanged the piston itself (not sure if it "seized" because it extended too far, and can be re-seated once off the car), rebuilding shouldn't be terribly difficult. Had to rebuild calipers on the Spec Miata and it wasn't brain surgery though tedious; not sure that the S4's would be appreciably more difficult.