Miller_arch

I painted my calipers red on my 1995 C2, non-Turbo. Now looking to replace my caliper piston dust boots. I have confirmed from PET plus Pelican that my stock caliper pistons are:

44, 36 Front
34, 30 Rear

My pistons are pushed in at the moment. To confirm the size of the pistons before ordering the dust boots I measured the top of the piston (just below the chamfer on the outer edge of the piston) with my calipers and got 4mm LESS than spec on all pistons.

My piston measurements are not aligning with anything plus 26MM piston are not made for the rear caliper. My measurements must be/got to be suspect or the spec sizes are a nominal dimension.

In my search I have found sources for these boots and other good advice but no discussion regarding this specific subject. So I want to reach out to you guys (and gals?) that have done this project before to confirm that I should just go with the sizes from PET and move on.

And a follow up question: Do the pistons need to be pushed out to replace the dust boots or should I leave them in?

Thanks!

chris walrod

If these are not torn, leave them alone. If you are going to replace the boots, you might as well install new pressure seals. All seals and boots cost about $200 from places like Zeckhausen

To replace just the boots, the piston can stay put in the caliper. Not hard to do, but once your 'there', rebuild the whole shebang.

f8vr993

Show us some pics for the blind....

JasonAndreas

On the face of the dust boot (1st image below) you should see the Brembo part numbers?

20 4872 42 - 34mm
20 4872 38 - 30mm

I don't have anywhere near the experience that Chris has rebuilding calipers but removing the piston made the dust boot replacement a LOT easier for me (I couldn't get them out without removing the piston first). The pressure seals come out real easy with a dental pick, prefererably plastic so you don't accidentally scratch the bore but metal works just fine. And a cut piece of wood does a great job at keeping three pistons you're not working on in their bores and the piston you are trying to remove from launching out of the caliper when you're using air to push it out.

Bill Verburg

To add to the above use Unisilikon TK44 N 2 Porsche part# 000.043.117.00 available for assembly(there are also generic brake assembly pastes available from Dow)
this is what you need for 2 caliper rebuild as you can see the visisble portion of the piston is smaller than the hydraulic portion

Miller_arch

Many, many thanks for the wonderful info!!!

f8vr993

This is the reason why the RENNLIST is the BESTof the BEST!