C70 Updates/ rear caliper question and Thanks Topic is solved

[subzerocarfanatic]

I just want to start by saying I love coming here and love the community based help I get here,without you guys I would not be so close to having our C70 Convertible near ready to drive.I have addressed everything from leaks, to brakes, suspension issues and fixes and none of this would have been as easy as some of it was without you guys. I have the car running, all new suspension and all new brakes, I did find the leak on the rear calipers after installing new rotors and pads.
I have a question though,the rear caliper splits in to 2 pieces,where the small holes are so the brake fluid flows from one caliper half to the other and the 2 halves but together is where my leaks were on both sides,should there not be a small o-ring where the small recessed area around each caliper half mounts together?

[JimBee]

There are 2 tiny o-rings that fit into the recesses to seal the transfer of fluid between the halves.
You can see them here:
https://www.partsgeek.com/rz2gfry-volvo ... tent=Volvo&

[subzerocarfanatic]

I managed to find 4 small o-rings that fit perfectly in the recessed area where the calipers split,it fixed my leak issue. The image referenced shows the caliper piston seal and piston o-ring seal,the smallest one is the bleeder valve cap.

[850oldschool]

The best kind of rubber for braking systems is EPDM. O-rings intended to seal oil in engines and hydraulic systems are usually nitrile (buna-n). The proper o-rings to seal the caliper halves have a square cross section, unlike standard o-rings, which have a circular cross-section. The only place I've been able to find the right o-rings is here:

https://www.pmbperformance.com/catalog/ ... 694936.htm

[850oldschool]

There is also the Centric 143.39003 rebuild kit. It's the only kit I know of that has the seals which go between the caliper halves.