Vintage Calipers from 914-6 #11, ...the very first 914-6 to leave the factory Options

[davep]

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.

[Eric_Shea]

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?

[Aaron Cox]

quick change pad hardware... nice!

[davep]

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.

[Eric_Shea]

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... (IMG:style_emoticons/default/confused24.gif)

[Eric_Shea]

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

Simple (IMG:style_emoticons/default/wacko.gif)

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.

[burton73]

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

[Eric_Shea]

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.


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.


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.


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.

[Eric_Shea]

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.


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.


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.


I know, I know... all stupid little stuff but, I dig digging into these. (IMG:style_emoticons/default/wink.gif)

[Eric_Shea]

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):


Here they are:


The owner wanted lots of photos to document the restoration:


More:


Most everything polished out:


These are now waiting for a large shipment of stainless steel pistons from Stomski.

[Eric_Shea]

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:


Remember the first few shots in this thread? These should be a bit different:


The underside:


The unique handbrake arm:

[Eric_Shea]

Let the assembly begin!

First we installed the new handbrake arm seal on the shaft:


Next we slathered a bit of brake grease on the shaft before installing:


Next, slide the arm in the caliper housing:


and:


Then we install the clip to hold it in:


Done with the new handbrake arm assemblies:

[Eric_Shea]

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:


Piston seals in and ready for adjusters:


Pistons polished with new dust covers installed:


Inner adjuster in place:


We were able to reuse all the original inner and outer adjusters. We replated the lock nuts:


First piston in its new home. All of them went in like butter:

[Eric_Shea]

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):


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:


Done:


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.:


Left:


Bob Burton's #41 car has similar numbers (IMG:style_emoticons/default/wink.gif) :


Bob's outer 1/2 (nose) :


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! (IMG:style_emoticons/default/ohmy.gif)

[Eric_Shea]

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

The spring seat is added to the handbrake arm:


Then the spring:


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:


The hardwork is done. Now all we need to do is bolt them together:

[Eric_Shea]

Putting the spacers and the caliper 1/2 seals in place:


Bolt the inner 1/2 on and they look like they did in 1970:


Here's the bottom:


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! (IMG:style_emoticons/default/wink.gif)

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

[KELTY360]

Now thems purdy partz! (IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/drooley.gif)

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[sww914]

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

[PeeGreen 914]

(IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/drooley.gif) (IMG:style_emoticons/default/drooley.gif)

[Lou W]

Very cool, thanks for sharing. (IMG:style_emoticons/default/smile.gif)