Help ID calipers and compatibility

[htron435]

I'm trying to figure out exactly which calipers are on my 911 SC with big brakes, as I need to replace one (or possibly both).

No Porsche part number visible, just the Brembo number 20.4584.00 and 93 casting (year I believe)






According to my research, I believe that this is a 928 S4 from built in 93. I have read that the late 928 calipers are the same as the 993 calipers, even though the part numbers don't appear to be.

A Porsche dismantler lists different part numbers for the 993 caliper and the 928 caliper. Are they compatible? If different, are they the same physical dimensions, and will they bolt up to the same mounting point? Use the same rotor?

Here are some of the different parts numbers listed:





Any help or guidance would be appreciated. I need to know what my options are. Thanks in advance.

[Bill Verburg]

Originally Posted by htron435

I'm trying to figure out exactly which calipers are on my 911 SC with big brakes, as I need to replace one (or possibly both).

No Porsche part number visible, just the Brembo number 20.4584.00 and 93 casting (year I believe)






According to my research, I believe that this is a 928 S4 from built in 93. I have read that the late 928 calipers are the same as the 993 calipers, even though the part numbers don't appear to be.

A Porsche dismantler lists different part numbers for the 993 caliper and the 928 caliper. Are they compatible? If different, are they the same physical dimensions, and will they bolt up to the same mounting point? Use the same rotor?

Here are some of the different parts numbers listed:





Any help or guidance would be appreciated. I need to know what my options are. Thanks in advance.

Those appear to be the second version of the 928S4 front caliper, they are different from earlier versions in piston design and size. From the pics they appear to be v2 36/44 pistons.

If they are indeed v2 928S4 fronts then they are the same as 993 front. The reason for the different part #s is probably because of different feed and bleed configuration which has been changed any way for 911 mount. As long as the small pistons see the rotor rotation first and the bleed is at the top you are good to go.

rotors should be 930 304x32

[htron435]

Thanks Bill. What year range for the 930 rotors (or were they all the same)? VCI's website talks about an offset issue with them. Is this something that needs to be addressed?

[Bill Verburg]

Originally Posted by htron435

Thanks Bill. What year range for the 930 rotors (or were they all the same)? VCI's website talks about an offset issue with them. Is this something that needs to be addressed?

If you have SC/Carrera front fender than the rotors are going to be the old 78-80 style w/ a separate flat hat. The newer 903 fronts from '80 up are 1 piece w/ an integral 21mm spacer.

The older style can be either floating or solidly bolted up

[htron435]

So then I'd assume that front calipers from a 993 c4 would work as well?

[Bill Verburg]

Originally Posted by htron435

So then I'd assume that front calipers from a 993 c4 would work as well?

yes, they are just a different color

C4S would be different

[htron435]

Okay, thanks Bill!

[Mothy]

I went down this same path, and with Bills good input as well, and the combination of these on the front (with VCI adaptor, flat hat and rotor) and 964 caliber on rear.

Very happy with the result. Balance is good, thermal capacity of turbo rotors better than careers or sc and they still fit under 16" rims.