fraggle

ugh. Just read this thread and am not finding it comforting news. I have an '87 and want to go through and rebuild everything. What was the cut-off for 'new-vs-old' style? Are there some visual queues? Why the hell would anyone stop selling just seals? Something like this shouldn't cost more than $20/wheel?? I just spent months and months waiting for suspension, I would rather not go through a similar experience again for parts that should be relatively cheap.

hacker-pschorr

fraggle - if your 87 S4 has piston squirters it's probably an early one.

928drvr86.5

I cannot verify whether or not the rebuild kits are available for the earlier 86.5- early 87, I.E. dust boots and seals. I needed a piston (messed it up while repainting calipers) and i was told by the Brembo engineer i was dealing with at the time that the pistons were no longer available. I am assuming that the boots and seals are still available.

Paul D

Here are some pictures someone posted a while back. First pic is of the early style brembo piston/scraper ring/pressure seal.


Here is a pic of the newer style piston/dust boot/pressure seal.


You will want to check with PET to verify the diameters of the pistons in the calipers as they were changed from year to year. Before you are buy anything make sure you can return it for a refund/exchange if it is not the right size. Good Luck!

Darien

Sweet!!! Paul, is there lube in around the piston?

daveo90s4

Apparently the inner compound in the flexible brake hoses can 'age' and as it deteriorates it tends to block the inner tube - a bit like hardening of the arteries. This means that when the brake is released some pressure stays in the line on the piston side the blockage. This then holds the pads against the rotor with a small force - enough to build up heat. If you do remove the rotors you should also check that the flexible hoses are intact inside.

Paul D

Darien - When I reassembled the calipers I used a modelers paint brush and dabbed clean brake fluid in the piston bores and pressure seals and the pistons themselves. They slid right in and have been working fine with no issues.

fraggle

Forgive my ignorance - piston squirters? Bear in mind I haven't taken anything apart yet so something that might be obvious had I done so currently isn't.

Daniel Dudley

CRC makes a red brake grease that makes a good assembly lube and helps to keep the bore frome crusting up as it fills the gap between the two seals. An alternative to a rebuild is to clean the pistons with spray silicone and a rag and then retract them. Force them back out and repeat until they free up. Also, it is important to make sure the pads themselves are not binding in the caliper housings. The pistons could be fine and it could be that the pads are not retracting due to corrosion around the edges. This is a very common problem, so check out the pad mounting surfaces as part of your R&R Good luck !

hacker-pschorr

I was somewhat kidding - piston squirters are in the crankcase - squirt oil on the bottom side of the piston. Only early 87's had these.

fraggle

doh that was all I could think of!!! But figured I couldn't be that far off. swallowed the hook, granted.

I figured, at minimum, I'll tear everything apart and clean it all. I'm just worried that if something goes "wrong" during disassembly (which NEVER happens) I won't have a source for spares.

I'm considering having some custom made. Is that possible? I have 'sources' in the high-tech industry that make all sorts of crazy stuff.