alloy brake caliper

[69911s]

i have a 69S with alloy calipers and the front left was leaking so when i removed it i noticed some corrosion on the lip where the seal goes. Is this ok to use or will it just leak again? is there another direct replacement for the front calipers or do i have to try to find another alloy one to replace that one which i know are real expensive. i would change both if i could replace with another caliper but i was told i would have to change spindle and rotors.

[moneymanager]

Do a search here. There have been several caliper rebuilds over the years, one or two of which were done by real experts who can probably fix yours or confirm it must be replaced.

[Flieger]

Ask Eric Shea at PMB Performance or search on the early 911S Regsitry

www.pmbperformance.com

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[DanielDudley]

That looks like it would clean up to me with Scotchbrite. How is the piston ? Corrosion and pitting on the piston that won't clean up means you can't just do new seals.

[69911s]

i have brand ss pistons the corrosion is pretty rough. i was thinking about trying to clean up but don't want to make things worse if it can be repaired properly. the inside where piston sits is fine its just on the outside where seal sits. i am thinking of trying a new seal and see what happens.

[RoninLB]

Originally Posted by DanielDudley

That looks like it would clean up to me with Scotchbrite.

mine cleaned up and was worse than the pic

[Eric_Shea]

That caliper should be de-anodized, cleaned and re-anodized.

They usually come out looking nice when done:

[911pcars]

Your calipers look perfect Eric, but I don't think normal caliper rebuilding needs to go to that extent.

If the bore is smooth, there shouldn't be any sealing problems. As suggested, use crocus cloth and/or a Scotchbrite pad and carefully remove any corrosion buildup. wash thoroughly in hot soapy water, water rinse and blow dry with compressed air. The seal area is where corrosion was trapped. When rebuilding, apply some Dow 111 to this area to help reduce moisture buildup and corrosion.

Sherwood

[Eric_Shea]

Sherwood,

What's "normal" about a vintage S-Caliper?

Looking at his caliper picture, almost all of his anodizing has come off. I "really" value S-Calipers as I think they'll get even more rare as time goes on. Especially if people remove the anodizing with harsh abrasives.

After 40 years... I personally would re-anodize every single one that looks like that. It will help preserve the caliper for another 40 years. You wouldn't scratch the anodizing off your wheels with Scotchbrite right?

Crocus cloth and/or Scotchbrite will only further erode any anodized finish that remains. Sorry... can't sign up for that recommendation. I kinda understand but...naaaa, I guess I don't.

A 1969 911S is not something you want to "cheap-out" on. Find an anodizer willing to mask off the pins. Do it right. Not cheap.

Call me if you need any advice. I can give you tips on what to tell the anodizer to get the proper finish.

[911pcars]

I was referring to cleaning up the cylinder bore. I suggested crocus cloth. Nix the Scotchbrite in this area.

Furthermore, merely anodizing won't restore the caliper to the level shown in your example. It looks like the caliper was prepped by bead blasting and/or other surface finishing before anodizing. This is not a mere undertaking unless calipers must attain a threshold of concours prep.

Sherwood

[Eric_Shea]

We take them to our anodizer and that's what they do. Kinda like taking a nice set of R wheels to Harvey. It cleans up all the bore issues at the same time.

They're simply polished, then etched then re-anodized.

Again, I guess I was playing off the comment: "I don't think normal caliper rebuilding needs to go to that extent". I didn't realize you were just talking about the bore.

It seems you think my recommendations are excessive. For a 69 911S we can agree to disagree on that one. I'm OK with that. I just think that car and those caliper should be finished properly. Building calipers is not rocketry and, he's 1/2 way there.

Just trying to help where I have the knowledge to do so...

[piggdekk]

Hello,
I'm resuming this old post becuase I was planning on rebuilding my S-calipers over the winter, and I'd really like to do it properly.
Assuming I don't find major issues, how should they be anodised? I read Eric mentioning that the PIN should be masked, should the bore be masked too?
Eric, anything else I should tell to the anodizer that You're willing to share?
many thanks
luca

[Eric_Shea]

The pin is steel. It will electrify in the anodizing process so it must be tapped off. "IF" (and this is a big if) you can find an anodizer willing to do it. 99.9% will not do it.

You can remove the pin and the subsequent knockback mechanisms from the pistons if you'd like. That's what ATE eventually did back in 75. Most 908 calipers did not have this mechanism either so... I know it's not stock but, it really wouldn't hurt to remove them. "MAKE SURE YOU GET ALL OF THE STEEL OUT" if you do this method.

Anodize the bore and all.

Thought I'd share because that picture is of an older finish. We've come a long way to make them as close as possible to the original casting/anodized look while still cleaning the surfaces.

[piggdekk]

Many thanks Eric,
and yes, those pictures do look great. My car is a 71, so I guess the correct finish would be the clear, not the gold. My gutt feeling is that Your parts look even better than the ones leaving the factory in the 70's.
I guess my next question is how to get the pin off without damaging the calipers. I don't care about preserving the originality, and I can't see the need for the knock off mechanism either.
I'm 100% sure that I will never find a place where they would mask the pin anyway.
thank You
luca

[Eric_Shea]

Break them off and take them to a machine shop to remove the remaining post or... just take them to a machine shop and say "remove the pins"

[Fishcop]

Just to echo Eric's recommnedations; I recently did the whole job myself and used a local anodiser. The finish isn't quite as nice as what Eric achieves, but they still look awesome and are protected for another 30-40 years.

It's not rocket science, and unlike fuchs, I don't think it's wise to just blast and polish S calipers as the wet road environment and extreme temperatures the calipers endure means they'll deteriorate quickly without the anodise layer. FWIW my anodiser was just too scared to mask the pins for fear of failure and terminal damage (at least he was honest), so I removed the pins and knockback mechanisms altogether - as Eric says, this was a factory decision in later years.

And I give a shout out for Eric's hard anodised alloy pistons rather than stainless (same rough price) - lighter and compatible metals, so internal corrosion damage should be a thing of the past...

[piggdekk]

Thanks all for the hints. I'll surely look into the hard anodised pistons from Erik when I pull the calipers (just waiting for the rainy season).
If I understand correctly the procedure to get a good finish would be:
1. getting the calipers de-anodised
2. polish them and remove all signs of damages/corrosion
3. get them anodised again
Basically I need to convince an anodiser to take the plating off first, and them plate them again.
luca

[Fishcop]

An anodiser won't work over the top of old anodise. Stripping the old and refinishing should be part of the service.

[piggdekk]

thanks John,
is the first time I get something anodised and I don't have any experience whatsoever.
luca