Brad W

Putting these on my 82 and would like to know what they came off of. Any help would be great.

RyanPerrella

Fronts look like Big blacks from a GTS or if they are smaller could be a 993 caliper

Brad W

I think they came from a 911 and I looked up the part #.
965-351-423-01 and the 928 # is 928-351-423-02. Just trying to see what the difference is and if I can use the same rotor.

ROG100

Brad,
I am pretty sure they came off a 993.
I will do some more checking.
Roger

cobalt

965-351-423-01 These would be medium S4 brakes off of a 91-92 3.3l turbo. These used the same 48mm pad along with a 322 x 32mm rotor. Assuming the rears are from a turbo also. If so these would be part numbers 965.352.421(422).12 and used 34/30mm pistons along with a 299 x 28mm rotor vs the 928 which uses a 299 x 24mm rotor. Although as Ryan said the casting looks more like a 993 rear.

Brad W

Anthony, the guy I bought them from said the came off a 93 993, not sure if it was a tubo or not. I compaired them side by side to stock S4 brakes and they apperar to be the same all the way around except for the script is flush and the S4 was raised.

So both take a 288 MM rotor then would the only difference be the width of 28MM vs 24MM ?

cobalt

Well considering they didn't make the 993 in the US until 1995 I would assume something is not correct.

The 993 starting in 1995 used another version of the front medium S4 caliper although my understanding is their part number was 993.351.421(422).00. These used the 304 x 32mm rotor instead of the 965 part number which used the 322 x 32mm rotor. It might be possible to use the 965 caliper with a 304 rotor if the pads on the caliper are machined down to adjust for the dia offset.

I would verify part numbers if you can to determine actual application. It would appear you have one bolted up to the car so you might try putting the disc on and seeing how it aligns itself. If there is a gap between the rotor edge and caliper than you have the 965 parts and would need to either machine the caliper or purchase the bigger rotors.

Assuming the 993 caliper is the rear than the only differences are it requires the 299 x 24mm rotor vs the 299 x 28mm rotor and both use different offsets. The 993 caliper is a common upgrade for the rear of the 964's this is a direct bolt up to these cars I believe the offset is the same as the 928. The turbo rear caliper will not work with the 964's and I believe the 928's without extensive work.

RyanPerrella

Brad,

In short, it doesnt sound like these are the ideal calipers for a 928 sadly. Good thing is that they can always be resold and if you got a good deal on em you could still make some coin.

cobalt

Actually if they are 965 front calipers all you would need is the bigger rotor or machine the mounting points down and if they are 993 and do bolt up you should be Ok although you wouldn't be gaining anything over the stock S4 brakes. The larger rotor would be a plus.

If they are 965 rears i would say you might think about selling them although they look more like 993 parts than 965 rear calipers.

I am attaching a picture of what you need to measure. This should be a 928 caliper and the 965 would be taller

one other thing IIRC the 993 and 965 rear calipers use a 12mm fitting I believe the 928 used 10mm rear fitting and you would need an adapter.

cobalt

I found these pics of 965 calipers as you can see they have ribbing the 993 units don't. I would have to assume the rears are 993. The other picture is a 993TT big red rear or medium S4 size caliper.

Brad W

I can't tell what you are measuring. I will put a stock S4 rotor on the front and get a pic put up. As far as fitting the rears, I think there is a difference between the 82 rear mount and the 87. I have the 87 mounts so I will test fit these also.

cobalt

Sorry that is the inside of the caliper where the mounting bolt comes through and attaches to the uprights. This is longer on the 965 parts to set the caliper out from the spindle more.

Brad W

The stock S4 rotor fit perfect. I do not have the rears on yet but I looked at Rogers old rears off his GTS and the size is identical except for the larger piston.

RyanPerrella

wow those are some rotors you got there!

I have to ask, would it not just be easier to resell and get bolt on S4 parts?

Im all for upgrades, but unless you can fit a larger than stock rotor, i dont see how modifying these to fit is going to make anymore sense then just fitting S4 units?

Brad W

Ryan, thats too easy.... So far everything looks bolt on to me and remember this is a 82, so any brake mod should be better. And the rotors will be cross drilled (new). just checking the fit.
If they end up not working for me then I will upgrade my 80 911 and put them on that car.