333pg333

Just trimming off the dust boots in the newly rebuilt calipers and found that 4 of the 6 pistons had these rubber seals under the boot.
Seemed to be inhibiting the piston from going all the way back in before they were removed but why would there only be 4 out of 6 and what is their purpose? Is it part of the fastening for the boot perhaps? Is there any issue running without them? For racecar so boots not required.

JET951

Audi calipers perhaps?

George D

LOL. Had to look twice.

333pg333

Ha, fair call.
But what are they?

Dutch944

Normally they would look like the oil scraper rings inside the brake cilinder, they are about 3mm from the top to prevent oil from bursting out of your calipers, i'll send youna picture by email if i can find one!

dmcampbell

Scraper rings designed to protect seal by removing debris from piston as it retracts into the bore of the caliper.

BoostBuggy

Something here doesn't quite add up. The 6 piston calipers never had the old style "scraper rings" These look to me like the pressure seals. That said, for the calipers to work i.e. not bleed fluid every time you stepped on the stop pedal there would have to be 6 seals, not 4. I assume there were sitting in a groove in the bore of the piston, correct? I don't understand how they could have been under the dust boots.

There's a number of things that don't quite make sense or add up to me here. I have rebuilt the porsche 6 pistons calipers quite a number of times. Feel free to PM me here to discuss further.

333pg333

This is what it looked like before we removed the boots. I bought these from someone in the US who had them repainted and bought a rebuild kit. That's how they turned up to us down here.

BoostBuggy

PM sent

You're right. Something is definitely wrong here.

333pg333

It appears that the pistons have been installed backwards and they tried to squash the seals in under the boot. Along with the wrong size custom rotors that we just received this brake upgrade isn't going so smoothly.....

Dubai944

Backward pistons, missing pressure seals.....?? I'd be checking the rest of those calipers carefully. Are the bores scratched, are the pistons and seals even the right size, make sure there is no paint in the crossover pipes or bleed nipples etc... Some people should stay away from DIY!

333pg333

Yep. Going to buy rebuild kits and start again.

Dubai944

Dave Zeckhausen is good, if you can't find what you need.

http://www.zeckhausen.com

Dougs951

I just rebuilt my Gt3 calipers and those also don't look like oem pistons either....

Duke

IIRC the stock pistons should be ceramic and not heavy steel as found on the Cayenne calipers etc.