ChewisHamilton

Hi Everyone,

A few weeks ago i was doing a pad swap on my 2014 S. I encountered some stuck pistons on the passenger side front and left the old pads in for a few weeks.

Tonight I took the offending caliper apart, planning to replace boots and seals only to find scoring on two of the pistons after I cleaned them in the ultrasonic. It’s the largest and smallest diameter that are impacted.

I’ve seen rebuild kits that are +$500 and include all pistons. Wondering if anyone has a source to buy only the pistons i need, not the entire kit?

also, the $15/caliper seal kit from oreilly is legit. I was skeptical on fit but they do work.

ygmn

what about bores?
no damage? normally both piston and bore get damaged together.

ChewisHamilton

Good point. I didn’t inspect the bore as well as I should have prior to reassembly (figuring if they were sealing before on the section of the pistons that was undamaged I should be fine).

Edit: with piston damage I assumed those can’t be salvaged as they won’t seal. If there were similar levels of bore damage what is the risk of continuing on with this particular caliper? I wouldn’t think that minor damage to the bore after the seal would effect much… but this is my first brake rebuild so an honest question.

Picture of one of the pistons below:

ygmn

Possible outcomes = Piston could stick, leak or work.
2 out of 3 are not good for your health...

For me when rebuilding calipers you need to hone the bores which might mean oversize pistons and well just not worth it.

Easier, safer and normally cheaper just to just get new calipers. and if you buy from FCP Euro; you get lifetime warranty and never have to worry about them again.

Mojo20032004

Rockauto.com has the piston replacements in stock. I used them before on my daily driver that has brembo 4piston calipers and rebuilt the brakes myself with any issues. Just make sure everything is clean. Buy new seals as well.