Are '67 911S brakes different from a normal '67 911?

[Survivor67S]

Im getting ready to rebuild the brake calipers for my survivor '67 911S and was wondering if the "S" model brakes are the same as the "normal" model 911. My car came with kits to rebuild the calipers, but the part number comes up as that for a "normal" 911. I can't find any other part numbers for "S" calipers though.

I know later 911S cars had the aluminum calipers, but the '67 did not. Just wondering if the brakes were bigger or different somehow even if they weren't the aluminum type.

[Bill Meyer]

The S had vented rotors front and back necessitating a spacer between the caliper halves. Otherwise the caliper and piston are the same as the normal 67. Hope that helps!

[Survivor67S]

Thanks for the info Bill. I may need to separate the two caliper halves to free up a stuck piston. I've heard that there is a gasket (or two perhaps for the S?) between the calipers that must be replaced. Are these available anywhere?

Thanks

[tomkirkcis]

Hi, I have dealt with Eric Shea to rebuild brakes for my 911's and 914-6. He does great work and is very easy to do business with. I believe he sells the rebuild kits and parts. The two havlves are joined with a flat o rings. Here is Eric's web site. best of luck tom

http://www.pmbperformance.com/page/page/1477335.htm

[ttweed]

I may need to separate the two caliper halves to free up a stuck piston.

Don't split the halves unless you absolutely must--you should be able to remove the piston without doing that, unless it is rusted completely solid from years of sitting, in which case the bores are likely to be so pitted as to be unuseable anyway without sleeving. Make sure it is not frozen or cocked in the bore (use a lot of penetrating oil on it and a small C-clamp to push it in slightly to break any adhesions and center/align it), then apply increasing air pressure to pop it out. You may need more than the 125 psi that most compressors are regulated at to do it. Hold the other piston in with a C-clamp and put a block of wood between them to cushion the stuck piston a little when it finally flies out. I have also heard of people using grease pumped into the caliper with a grease gun to remove the pistons, but I have never tried that, I have always been able to get even the most recalcitrant of them out with 150-175 psi of air through the feed hole with a rubber-tipped air nozzle.

For sure, check availability and obtain the O-rings first before you do split the caliper, if that is the only alternative. White Post can resleeve your cylinders if they do happen to be too pitted to reuse, or completely rebuild your calipers for you, but it ain't cheap.

TT

[Schläfer]

If you do split the calipers I can help out with the O-Rings you'll need. They are an oddball size and very difficult to get hold of. For my needs I couldn't get the calipers replated properly without splitting them.

Cheers
David

[Neil '67 911S]

Hi,

I believe that the rebuild kits for the '67 911S rear calipers are unique and tough to find. Jim at EASY rebuilds them for $100-125 per caliper, a real deal. He will also media blast them and paint them with a nice, silver Wurth lacquer. Great guy to get used parts from. Honest as the day is long and he loves to chat with friends. Oh, and he separates the halves for more effective cleaning.

Jim Breazeale (Pronounced Brazil)
EASY
4060 Harlan, St
Emeryville, CA.
(510) 653-3279
http://www.easypor.com

It's not a good idea to blow compressed air into the caliper. Pascal's Law states that a small pressure (125 psi) operating on a large surface (caliper piston) creates tremendous force. Go to your FLAPS and buy a cheap grease gun, a quart of really cheap motor oil and some zirk (grease) nipples. No fear of damaging yourself or worse still, the fresh paint on your Porsche from flying caliper pistons.

The Zirk fittings are the same size and thread pitch as the brake line fittings. Screw the zirk fitting into the caliper, pour the oil into the grease gun, pop the gun onto the zirk fitting and pump away. Use a small c-clamp to modulate the piston movement. One will definately move sooner than the other. Make sure that both are moving well before letting one or the other pop out of its bore.

Sure you can use brake fluid, but brake fluid and paint don't mix, so why that the chance.

- Neil
'67 911S (Ol' Ivory & the Rust Bucket)
'67 912/356D (Ol' Blue & Ol' Beige)
'65 356C (Ol' Grey)

[ttweed]

It's not a good idea to blow compressed air into the caliper....No fear of damaging yourself or worse still, the fresh paint on your Porsche from flying caliper pistons.

I'm glad someone with experience using a grease gun posted, but I have never had a problem with "flying pistons" using air, and it seems to me a bit cleaner method, since you don't have to deal with the oil or grease cleanup.

The piston is guided by the bore and can't go anywhere but straight out after it pops past the seal--as long as you use a block of wood to cushion it and take up the space the rotor usually occupies, there is no problem--it doesn't have far to accelerate, and it can't fly loose. If you exercise reasonable caution, don't put your finger in the way or something really dumb, you aren't going to hurt yourself or anything else. On a normal piston, it might take 30-60 psi to pop it out--only a very stuck piston would take 125+.

This is, in fact, the factory procedure from the repair manual. They recommend starting with 2 atm. (29 psi) and increasing pressure as necessary.

TT

[Survivor67S]

Thanks for the advise Tom I will try your methods. Thanks to everyone else as well...with your help my '67S will drive to the SD Parade in July!

[Neunelfer]

I believe these are the calipers we spoke about on the phone last week. Thanks Tom for the plug... your -6/GT calipers came out "fantastic".

We restore these calipers and that's what I would recommend here. This car has been sitting for (if I recall) more than 10 years. It will be nearly impossible to get the pistons out with air at this point.

To speak to the air vs. fluid issue; I always use air first. However, I've found air will only work on a caliper that is in "decent" operating condition, meaning; the pistons move "fairly" freely. If the caliper has been working but has recently frozen then TT's clamp procedure can work to get the piston moving again and you "might" have success with air.

Neil has a point, the velocity can be staggering but I doubt if any harm could come from it. Most damage has been caused to the piston or the opposite dust cover seat and not the human. My only concern with a weekend mechanic doing this is not prepping the inside of the piston area properly in order to avoid such damage. You should use a piece of wood and I shove a rag in there as well. Again, to speak to Neil's point... don't put your digits in there.

If they've been sitting for a while you can try to soak them for a week in one of those gallon jugs of Gunk carb cleaner. An M-Caliper "just" fits. Rears drop right in.

Really bad pistons need grease or any other type of fluid (fluid does not compress which is the problem you have with air on these severely frozen calipers). I use grease because it is convenient and you can control the extraction process with a grease gun. The good news is, the fitting on an El Cheapo Harbor freight grease gun (take the nozzle off) screws right in to the metric fluid inlet on the caliper. Leave the bleeders open until the grease starts to come out and then close them off and pump out your pistons. No worries about high pressure etc. They simply "plop" out. Yes, there's some clean up but, we simply wipe them down and send them to the platers, and, it beats the alternative... the calipers would basically be toast. This is one of the only ways to restore these calipers.

Sorry guys... I have the factory manual as well but I doubt very much that air will even touch these pistons. They may be in better shape than described to me but... that would be a lucky day.

There is also a trick to getting both pistons out which involves plugging the previous bore once one of the pistons is out. I take the inner piston out first and then do the nose cone or outer piston. This allows me to position a block off plate in the vise.

I also recommend splitting the calipers at this point. This is not a bead blast repaint thing... this is a 67S and they should be restored properly. This includes replating and basically restoring from the ground up.

Regarding the kits; these are fairly common "except" the rears. You need a supplier that knows what you're looking for. Basic 911 rear brakes have had 38mm pistons from 66-83. Because of this, many manufacturers have superseded the odd-ball part numbers with a one size fits all 911 kit. These rear pistons are indeed 38mm but they have smaller tops and the dust boots on the common kits do not fit properly. We've done early S calipers in the past and the rears on these cars are different for sure... crossover pipes and all. Very rare at this point.

If these come in, I'll post a step-by-step tutorial with pics so you can see the progress. Pete wanted a tech article for Excellence and, it's all but written but the pictures didn't come out that well. This would give me a good opportunity to get some grungy old stuck calipers and show the process.

My $.03

Eric