Well, we received the calipers to restore for #11. This is the very first 914-6 to leave the assembly line. The car was used by the factory as a demonstrator car. They loaded it with all sorts of go fast and stop fast goodies.

In the go fast department this car received a 2.0 twin plug motor.

In the stop fast department we will see some odd things. I noticed a bunch of "little stuff" that you don't see every day on your standard 914-6.

Let's start with the rear. These are the real deal. These are real factory 914-6/GT calipers and I would dare say the very first set. Here's some of the standout differences from your standard 914-6 or even later GT calipers.

#1 - These have the 911 M-Caliper hardware for sure. The first thing I noticed was the Ribe head cap screws with the R6 head. This differs from the rounded shoulder Ribe R5 hardware used on the 914-4 and 914-6 calipers of that era.

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#2 The next thing I noticed was the spacers. These are the round shouldered spacers from an early rear M-Caliper of that era. Later GT and Ferrari calipers have sharp or squared off spacers that better match the caliper mating surfaces.

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#3 The final note (of distinction) for the rears would be the color. It seems as though these are definitely "yellow" cad plated. On other 914-6 calipers it was difficult to tell because they were so light. When we tear into them we can usually see some yellow on the mating surfaces but, again, it's very light in color. These look to be 914-4 yellow in color, meaning; very obvious.

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Thanks for the little items that make the difference.

Now for the fronts...

S-Calipers. Early S-Calipers.

Most S-Calipers have the rounded off bull nose. These S-Calipers have a more squared off nose with little casting wings on them.

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Here's a shot of a bull nose S-Caliper side-by-side for comparison:

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Notice anything else? How about the color? Again, most S-Calipers have a greenish gold tint from a sealer used in the anodizing process. These early calipers are simply anodized aluminum. Here's another side-by-side for comparison. 914-6 #11 on the left, later model S-Caliper on the right.

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Here's some wierd notches that I'm still scratching my head over. These are just on the left caliper... anybody?

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One more showing both...

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Maybe they were a prototype that got changed along the way? Maybe they were borrowed from some other European car model on short notice?

I can look for those notches on my Dad's 911 this weekend if I can make it home . . . his 911 seems to have early S calipers like those. They are even the same color (atleast thats what I remember them looking like when we rebuilt them).

Are you talking the S-Calipers? I don't think so. They should have had S-Calipers as standard equipment the previous year on all 911S's. Only the left caliper has those notches...

Guess I've been sleeping. What/where's the story on the restoration of #11? A thread here? Somewhere? I wanna know more. Please!

#11 was recently purchased. It was in storage in a barn in Pennsylvania. The factory commissioned it off the line as a demonstrator car. It was then given to a friend of the family here in the states. Gary Wigglesworth bought it off that individual and stored it for nearly 20 years (maybe more).

It was recently purchased from the Wigglesworth estate, along with a bunch of GT goodies, by an associate who had us do his original GT calipers.

I've been trying to get Pete in touch with him to do a full story on the car as I feel it's one of the coolest, one off 914's in existence.

This is wonderful stuff Eric.

Working with original pieces like this must be a real treat.

Precious cargo i would say.

And the precursors of what was to come. Very Kewl.

Very solid pics and descriptions.

Thanks,

Clayton

Clayton

A member here has #12. you should contact him and see if his has the same or different calipers. (GMS)

Yeah... I don't know too much about Glenns' car.

Eric,

Would this have been the Stunden car?
Pat

Pat,

I'm not sure.

Probably someone like the Dr. or Wolfgang might have more historical info on this car.

I found some pics of the Stunden car lately... this isn't it.

I dug into the first S-Caliper this evening... man, talk about bad shape. Don't leave your cool historic Porsche sitting in a barn. Everything came apart OK though. It was a task. Pics tomorrow.

Thanks for sharing the pics!

I'd be curious if the brakes from 914114 are the same...

I wonder if Sam is around to take some pictures.

I would doubt it. I think it depends on the engine. Others here could tell us what engine that car has.

The strange things about #11 are:

1. It was the first "production 914-6" listed off the line.
2. The factory grabbed it as a demonstrator car.
3. It was a factory hot-rod (2.0 twin plug)

I think because it was a factory demonstrator car and a hot-rod, so to speak, they decided to put the best brakes they had on it.

A little shop research last night:

I found another S-Caliper with the casting wings "but" it was post 1971. If you look at the second picture in post #3 you'll notice two circles on the top of the later caliper on the left. Inside those circles is stamped an "X". While looking at the factory manual this denotes a new piston and a date range later than 1971 (I believe... manual not in front of me at the time of this writing). I found one of the early style calipers (wings) with the circles cast in it and the X's...

A pockect for the keeper. so the pad can retract further. 1.5 extra pad for endurance racing. or as stated protype , fittment issues

here is my oddball caliper

908?

Well, this is what I normally think of as the 918 or 914/6 GT caliper that I saw on 9140430033. At one time, the fellow that I got my oddball from owned #0033. Notice the coil spring for the pin, and the spreader spring is hinged. What you can't see is the pegs below the pads to position them and keep them from falling out.

Yours looks almost like a hybrid. It has that same "flat" surface on top like the 908 and it has a unique pad retaining mechanism but obviously not the quick-load style the 908 has.

From my understanding, the 908 varies in that quick load pad system and the width (for thicker pads to last a full race, or thicker rotors)... otherwise, it's an S-Caliper. No?

quick change pad hardware... nice!

Well the 908 caliper also has larger pistons I believe; 49.5mm as opposed to 48mm.
Have you ever been able to repair broken socket head bolts that hold the back cover on? I have one where it is broken internally; at a good depth actually.

Yes, once. Simply took it to a machine shop and they extracted it. It wasn't that deep. I've had others where the head was stripped (common) and I had to cut it off and use ViseGrips to extract the remainder. Heat works well on these. I use it on "all" of the bolts etc before I attempt to even turn them. Too much at risk.

Try (extreme) heat and a reverse bit.

If ruined it "may" be able to be rewelded and retapped. I think the alloy is pretty straightforward.

I thought 908 pistons were the same...

I found out what the notches were in post #3, last picture.

Simple

A recess for the retaining pin clips (is that what you meant Jeff, "a pocket for the keeper"?) Thanks to Bob Burtons S-Calipers for solving the mystery.

Maybe Bob can weigh in here. Bob's front calipers are identical. It is my understanding that Bob's #41 car was hot-rodded a bit, maybe back in the day. These are simply very early versions of the S-Caliper. Bob didn't have spacers in his rears and they were standard 914-6 fair from what I could see.

The story is this car #41 was a project car for Troutman-Barnes. The car was owned by Peter Miles who worked for Dick Troutman and Peter Dawe from Dawes Motersports built the motor. This was back in the day. In the late 1970s this is from Peter Daws own words on the eBay ad in the questions and answers this was one of the reasons I paid $15,000. For a 914-6 not running. As to the brakes all I knew was it has Modified Front 911s Calipers. With cross-drilled “S”rotors. That was the ad in eBay. I still email the PO.

Bob

I don't see any modifications on the S-Calipers, maybe they meant modified by adding S-Calipers. S-Rotors are the same as any vented 911 rotor of that era.

Here's some shots of the #11 S-Calipers torn down.

These were a "piece of work". They basically sat and sat. This is the dust cover and subsequent metal support ring. The metal was so rusty it was like paper. It took a while to get these out.
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I preach about S-Calipers needing new pistons. About 80-90% of the time they do. Because of dis-similar metals they chromed the S-Caliper pistons. They sit and rust.
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The groove in the above picture is not a serious issue, the walls of the pistons are. The groove can be beadblasted and repainted, the walls can't be replated. The only remedy here is stainless steel pistons.
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Everything apart. The knock-back pins need to be machined out to re-anodize the calipers but, that's what it takes to make them new again.
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More on #11's 914-6/GT calipers:

The handbrake arm has a spring retaining slot cut into it. These are different from any I've seen. They have a "U" shaped groove and all the other arms have a squared off groove.

Here's a picture of the "U" shaped groove. In some regards, it almost looks as though these were cut by hand.
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Here it is side-by-side with Tom Kirkpatrick's 914-6 handbrake arm (they are the same as the -4 arms). You can see the squared off slot vs. the "U" shape.
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This is fairly standard among the early 914-6 calipers but, the inner adjuster gears are cut head-to-toe (left) and the later gears are slightly different with the crown at the base.
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I know, I know... all stupid little stuff but, I dig digging into these.

Quick Update:

Remeber those S-Calipers that looked so trashed that... well, they looked hopeless. Nothing is hopeless in restoration land.

We got a batch back from the platers today (from left to right, Bob Burton, Tony Samogen's #11, Kevin Koch and Glenn Sager):
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Here they are:
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The owner wanted lots of photos to document the restoration:
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More:
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Most everything polished out:
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These are now waiting for a large shipment of stainless steel pistons from Stomski.

Now for the GT calipers. Again, sorry for boring you all... this stuff is interesting to me. Again, these are likely the very first 914-6/GT calipers ever produced.

This car has such a cool story. I can't wait until it comes out in press. First 914-6 off the line becomes a factory hotrod/press demonstrator car.

Well, you've seen the before pictures. Here's the after and the build of these awesome little jewels back to their original glory.

Here's a pre-assembly picture with all the plated parts:
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Remember the first few shots in this thread? These should be a bit different:
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The underside:
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The unique handbrake arm:
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Let the assembly begin!

First we installed the new handbrake arm seal on the shaft:
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Next we slathered a bit of brake grease on the shaft before installing:
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Next, slide the arm in the caliper housing:
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and:
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Then we install the clip to hold it in:
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Done with the new handbrake arm assemblies:
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Moving on to the next phase, we get the seals in and the adjuster mechanisms locked into place:

Bored and ready for new ATE seals:
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Piston seals in and ready for adjusters:
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Pistons polished with new dust covers installed:
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Inner adjuster in place:
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We were able to reuse all the original inner and outer adjusters. We replated the lock nuts:
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First piston in its new home. All of them went in like butter:
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Next it's the inner adjusters. Again, the original pieces are like new (hard to believe when looking at the first pictures of these calipers):
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With new seals on the adjuster posts we load them up with springs, hats and clips and drop them into the housing. Next step is to press them in and seat the clip:
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Done:
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What I think is great are the original casting numbers. These are #1 for the right inner housing and #2 for the left. Both noses carry the #1 mark.:
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Left:
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Bob Burton's #41 car has similar numbers :
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Bob's outer 1/2 (nose) :
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We have a later set of 914-6 calipers in house that carry the #9 casting number on them. Some 914-4 calipers carry casting numbers as high as #43!

Some finishing touches and they're ready to bolt together.

The spring seat is added to the handbrake arm:
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Then the spring:
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Then it all gets topped off with the appropriate flat washer and clip. Later 914-4 calipers generally had one edge of this washer beveled:
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The hardwork is done. Now all we need to do is bolt them together:
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Putting the spacers and the caliper 1/2 seals in place:
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Bolt the inner 1/2 on and they look like they did in 1970:
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Here's the bottom:
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Well, all that's left now is to button up those S-Calipers and #11 should be good to go in the stopping dept. From what I understand, there is quite a bit of metal work still to be done but it's in the shop getting that finished off now.

I'm proud to have this job come across my bench. I think you all will love the car when it's done. Keep your eyes peeled!

I'll give a final update on the build of the S-Calipers once the pistons arrive.

Now thems purdy partz!

Very cool thread. Thanks for taking the time to post all of this.

Very cool, thanks for sharing.

Parts Porn!!!

I L O V E this stuff....

Great stuff! Thanks Eric!

eric, you should consider submitting a write up in excellence on these yourself. i find the reader submitted tech/how-to articles interesting. you write well, it would make a killer piece. nice work on the parts.

k

Thanks Kevin, (don't remind Pete... I owe him a caliper write up but my pictures came out bad... time to try again I guess)

As promised, heres the final installment... the S-Calipers. I think this will actually be interesting to quite a few people. It will show you what's involved in saving a valuable S-Caliper and help dispell the myth that there's a "cheap" S-Caliper bargin out there waiting to be found.

Remember what these puppies looked like from page 1?

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Again, one of the main problems we see on nearly 90% of the S-Calipers that come in is this... the plated pistons are rusted.

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These pistons are plated to avoid a dissimilar metal bond. When they sit (and vintage Porsches sometimes do) they tend to rust around the top and where the piston seal rests against the piston.

Steven Stomski of Stomski-Racing to the rescue. This is where the myth begins to smack of hard, cold reality. These are the best stainless steel replacement pistons out there but... you're now out $240.00

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Well... everything is back from the polishers and the anodizing shop and ready to get bolted together. These calipers have to be de-anodized, polished and then re-anodized. Myth-buster #2. That'll cost ya... the average cost on a restoration like this (with pistons) will be just North of $700.00

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New factory crossover pipes are a must for a restoration of this caliber. One was damaged in shipment and the other was just too rusty to plate up nice. We want #11 to look it's best... Oh, almost forgot, more ka-ching. These are almost $60-$70 a PIECE!

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Let's get dirty.

Fist step is to clean out the rear cover mounting bores with a M6x1 tap. There was polishing compound and other goodies in there that would make getting the new bolts in impossible. This is a pain (especially when you're putting together 4 pair of these...) Once the tap has been run through everything, we turn them upside down and dump out the crud and then blow it out with the air hose.

Polishing compound:

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The tap:

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Next the piston seals go in. Outer first:

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Then inner:

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Next it's time to put the dust covers on the pistons. They simply pull over the top:

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It's a good idea to lift the dust cover to expose the mounting area. Look around and make sure it's seated properly:

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Done. Pretty pistons all in a row...

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You are an artisan, my friend! Truely an artisan, and dedicated to his craft. We are fortunate to have you around!
Pat

Thanks Pat... I just dig this stuff. No real art here.

Now its on to installing the pistons.

The first thing we need to do is apply caliper grease to the seal and bore area. We also like to apply a little grease to the area the dust cover slips into. These dust covers are usually pretty tough to slip into their slots. The grease helps.

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Next we determine which side will be which (S-Calipers are interchangable) by putting the bleeders in. They always go on top.

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Then we position the pistons so the cut is facing 20 deg. into the face of the oncoming rotor. We use an old piston positioner to get the angle just right.

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We usually use a simple press to get the outer pistons in. These pushed in by hand but others can offer a tad bit of resistance. A special plate is used to press the dust seal into it's slot.

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Next we put new o-ring seals in the rear piston cover plate. These are unavailable so they had to be sourced via alternate methods:

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These shots didn't come out so well but... the cover plate then gets torqued into place in a cross bolt pattern:

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The inner piston bore is covered with caliper grease as above and the piston and dust cover are pulled into place with a hand vise/clamp.

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Top it all off with the new lines...

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#11... you are officially ready to go errrrrrr... stop!

Family photo:

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The fronts:

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The rears:

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Thanks for playing along at home

Absolutely inspiring, Eric!

Thanks for the show,

Thanks Wayne... these were a blast to do. I can't wait to see them on the car.