how to tell apart pre or post '96 rear calipers?

[rich_DTM]

does anyone know the physical difference of the early or late rear calipers?
i know pre '96 the discs were 170mm
and post '96 were 286mm

but how to tell the capilers apart as they have different part numbers for the pads!

[RobbieV]

Rear discs were pre 260mm and post 270mm.

as for telling the difference - no idea.

[GreyDJ]

That's strange, GM list the same pad for all Calibra rear applications.

All models disc pads 90485136

[bodgetastic]

Autovaux sent me out some exchange calipers and the pads didnt fit because the pin spacing holding the pads was different. Would possibly have a different size piston too but really not sure. I think they have different numbers on them though which might help identify them or you could take the part number from the old pads?

[big_gordy]

"you could take the part number from the old pads"

good idea i would say!

[GreyDJ]

The 90485136 is definitely the right pads for my late Turbo but I have found big problems getting the correct fitting kit as the springs for the pins are not long enough.

[Fraz]

thats casue they stopped doing the pins that go in from the front, you need to fit shorter springs and come in from the back of the backplate

[GreyDJ]

thats casue they stopped doing the pins that go in from the front, you need to fit shorter springs and come in from the back of the backplate

I am using the 'in from the back' pins, but the holes in the callipers for the pins are spaced too far apart for the pin 'hollows' in the springs.