Need help identifying alloy brake calipers

[D Miller]

I have some early alloy calipers which I need help identifying. One is incomplete with no crossover line or side cover and only one piston. The other two are a matching pair and appear as new or fully rebuilt.

All the calipers have 48mm pistons, 24 mm rotor slot, 61 mm pad slot, and 90mm (approx) mounting bolt spacing.

There are subtle differences in shape and profile or 'height' between the first and second types, but I am unsure how to measure these differences accurately. The first caliper is definitely a lower profile and looks like it was intended to run in a smaller diameter wheel.

The first four photos are of the single caliper, the last is of one of the matched pair.

Thanks in advance for any info.

Regards

Duncan

[mike curnow]

All looks like a normal 911 S caliper?

[davep]

The singleton is the late "S" variety used from about mid 1972, and on the first 930 turbo.
The pair is an early "S" variety from about 1969; the first version I think because there are no recessed circles, later the circles appeared, then came the circles with the X stamp. Finally the bull nose caliper came.

[D Miller]

Thanks for the info davep.

I am still a little curious though. The two calipers I thought were a matching pair have, on further examination, slight variations also.

Firstly the 'ate' logo casting is different, and secondly one caliper has a flat machined on it's outside face while the other is more rounded.

Both calipers have stampings on the top. One has the numbers 66 or 99 and an L or V, and the other has the numbers 428 and 24.

Thanks again,

Duncan

[davep]

Let me refer you to this thread about a very early 908 caliper that I own:
http://www.early911sregistry.org/for...ad.php?t=21244
There are many variations in the S calipers with the first use recorded about 1968 on the 908 and on some late 1968 911S. There were a few differences in the forging (?) dies and it would appear yours are sort of a mixed pair. If these are off of your '69 S, I'd like to know the VIN. If they are for sale or trade, let me know. Can you post some photos of the areas where the bleed nipples are installed, and the inside of the mounting ears. The very early calipers had shrouded nipples, and it was difficult to use a wrench on them; later they notched the area for better access. On most caliper the inside of the ear is just machined flat and is at right angles to the machined flat bottom. On my early caliper the inner side of the ear is milled with a circular end mill just like the outside. I'd like to get another caliper to match the machining of my 908 original, as well as the casting marks such as the ATE logo.

[D Miller]

These calipers are not from my 69S.

After reading the other post, it appears as though I may have one 908 caliper and one standard 911S caliper, but I will leave that to the experts to decide. If that is the case then the 908 caliper will be sold and I will keep the standard caliper as a spare.

Photos of caliper 1 (with the raised 'ate' logo and no casting line). I have tried to highlight the areas which are different to the other caliper and also the area on top where the numbers (428 and 24) are stamped;

[D Miller]

And caliper 2;

[davep]

I believe that they are just early 911S calipers, albeit one is a little earlier than the other. There are die differences which are not important. The stamped marks are found on all calipers, but do vary. The extra machining on the one caliper just gets rid of excess material for clearance. The 908 racing calipers have the quick pin pad release in one form or the other.

[D Miller]

Thanks davep.

Cheers