Caliper Rebuild

[DonC]

For those of you who have re-built their own calipers....any premature failure problems?

Thanks!
DonC
'90 535i in hovercraft mode

[Patrick]

No -not yet. Why?

[Karl]

Caliper rebuild is an easy project. The thing only has one moving part...
Seriously, I've done a couple with no problems. It requires no special tools. However, if you have a stuck piston it can be tough to remove. There's very little clearance between piston and bore, and any little rust/crud can jam it. The book says to use your compressed air gun in the brake line hole to blow it out, but... I've had better success using brake system hydraulic pressure. Remove the caliper but leave the brake line attached--then press the brake pedal to push the piston out.
Wish you well with it.

[DonC]

My inde mechanic says he does not rebuild calipers because they "don't last" - I think he wanted to sell me a caliper.

Anyway, I rebuilt 3 calipers this afternoon - really easy. Used air pressure to pop the pistons; cleaned everything up; put 'em back together. Did rotors, pads, and SS brakelines while I was at it.

Cheers!
Don

[MBXB]

What did you guys use the clean and prep the caliper before reassembly?

[DonC]

Lots and lots of brake cleaner.I think I went through a dozen cans of the stuff.

[Robin-535im]

Lots and lots of brake cleaner.I think I went through a dozen cans of the stuff.

I used brake fluid as a lubricant... you have to use something to keep the abrasion effect mild and controlled. Hone it until there are NO rust chunks left. There may be some pitting in the cylinder, can't do much about that except hope it doesn't make a bad leak. If it's pitted too bad you probably need a new cylinder, but might as well put it back together in any case and see if it holds.

HTH

Robin

[Marshy]

A friend of mine did one of my front calipers some 20,000 miles ago, and it's been trouble-free ever since. Some daft clot hadn't fitted the dust cover properly last time around, hence the problems with a sticky caliper. Suspect it to have been the inspecting dealer who told me at time of purchase that the caliper was pitted. Sigh.