Missing solid steel rings for Front, Aluminum Alloy S-Brake Caliper Rebuild Kit

[72doug2,2S]

Front, Aluminum Alloy S-Brake Caliper Rebuild Kit doesn't include the boot retaining rings. I searched for this but couldn't find anything. Anyone have another source? I can clean the rust off the current rings, but they're not in great shape.

[Magyar Kiwi]

Sorry no answer

[75 911s]

Doug,

can you post pictures of the caliper and the bores?

There were a few changes in the Aluminum S caliper starting with early race calipers for the 908 and 910. Some of those early calipers are different in regard to the pistons with stepped bores.

I think Eric Shea would probably be the expert on this or maybe someone at the Early S registry.

I've disassembled 3 sets and I can't for the life of me remember seeing those rings. I'm still researching because I'm downright curious.

[72doug2,2S]

[72doug2,2S]

[jrblackbox]

Ran across this issue awhile ago too. I don't think they were used on those calipers.

[75 911s]

I think I figured it out.

So the aluminum calipers have two areas that leak after they get corroded. 1. The piston bores. 2. The cap with the four bolts (the inner sealing edge where the big o ring sits.)

Maybe someone milled out those rings to line the bores so that the pistons wouldn't leak. I don't think that's a stock aluminum caliper part. Please someone correct me if I'm wrong. It's early here and only one cup of coffee that may or may not have kicked in yet.

Doug if you can, get me a good close up of the bores with some light on them. I imagine there is pitting where those rings sat.

In that case, those Aluminum calipers may be beyond the life span due to corrosion.

Edit: thought of another possibility. Maybe it's a different caliper boot kit that was installed.

[72doug2,2S]

[72doug2,2S]