A Tale of Three Calipers, Tell me about different RIBE hardware Options

[zoomCat]

I'm putting together a pair of rear calipers for a six, which the previous owner had replaced with 911 rears to get the vented disks. He didn't keep the originals, it was back in the 80's and nobody cared.
Here's what I've got so far:



On the left is a rebuilt stock 914/6 left rear. The plan is to add a spacer for vented disks.
In the middle is a 914/6 right rear, which I got years ago that already has a spacer. It will be rebuilt.
On the right is what I think is a right rear Ferrari 308 caliper, because the bleeder is in the wrong place. It can be a donor if absolutely needed. The rears the previous owner had installed are the first candidate for donors.

My question today is about the RIBE hardware.



On the left is the rebuilt stock, on the right is /6 caliper that had a spacer added. The fasteners on the left have sloped shoulders, while the other has more square shoulders, which I see on the front A and M calipers I've got.

What was original, either for the stock calipers or the GT calipers?
Is there any functional difference? Esthetically I'd like to get it all matching and correct before I send it all off to PMB, but that depends on availability.

[Eric_Shea]

Factory 914 six calipers had no spacers and used the “button” head M7x50 and 55 Ribe fasteners. (Caliper on the left)

Factory 914-6/GT “prototype” calipers used both the spacers and the fasteners from the new long wheelbase 911 S with vented rotors on the rear. Those fasteners were M7x60 and 65 “cap” head Ribe. (Caliper in the middle) This early spacer was machined not cast and they have rounded edges with machining marks on them. Remember, this was all new for ATE. Everything was solid rotors up to this point. They didn’t have a 60 or 65mm fastener on all previous calipers. These one off (41 off) prototypes used the 911 stuff all around. These cap head fasteners do not look like A-Caliper fasteners. They look like M7 versions of “M-Caliper” fasteners. M-Calipers used a “cap” head M8 fastener. A-Caliper fasteners are actually M9 versions of our 914-6 M7 button head fastener. M7 fasteners have Ribe R5 bit heads. A-Calipers, again, use an M9 version of our “button” head with a Ribe R6 bit head. Probably one of the more delicate fasteners to get apart because of the smaller bit head and larger M9x1 thread engagement. In contrast, the M8 M-Caliper fasteners use the M8 cap head with a much more robust Ribe R8 bit head. Much easier to remove without damaging.

The last caliper is a Ferrari 308 caliper. (Bleeder positioned under the handbrake arm). (Caliper on the right) These came from the factory with spacers installed. These would be a cast, more form fit spacer as identified by the casting line running around the spacers. By this time ATE spec’d the proper M7 x60 and 65 button head Ribe fasteners to use on these calipers as this was a production unit.

Hope that helps.