Shamstar

Doing a break overhaul on my '93 C2, as I've done the big red calliper conversion up front and have drilled Disks, was looking to match the rear with drilled disks... My question is, is there an OEM drilled disk available to use on the rears?
Many thanks Sham

KaiB

What are you running for rear calipers?

Bill Verburg

The 964 used the 968M030 rear disks, these are perforated and have the correct size and o/s for 964. You will want to use normal 993 rear calipers which are the replacements for 964RS rear calipers. They are physically the same as 964 4 piston rears but have bigger 30/34mm pistons

Please do change to the bigger 993 brake booster and m/c and remove the p/v on the rear lines

delanobe

What do you mean with p/v?

Thanks

Bill Verburg

911 from '85 and all 964, 993 up all use a p/v on the rear circuit
compare the brake torque @70bar line pressure, f/r, ratio

911 thru '83 1440/9.69, 1.491(this is close to perfect for these cars)
911 '84 thru '89 1440/1186, 1.22 w/o p/v, 1440/639, 2.260 w/
964 1974/1139, 1.734 w/o p/v, 1974/615, 3.210 w/(4 piston rears)
964RS 2381/751, 1.508 w/o p/v 2381/707, 2.792 w/

the 964 uses a 55bar p/v, below 55bar the w/o p/v is the # to use, above 55bar the w/ # is used

for street use p/v or will rarely make a difference
for track use(why else use big brakes?) you want to get the rear involved as much as possible
benefits
fronts run cooler and last longer
shorter braking distances because the rear is adding more to the work and using more of the bigger rear tires potential

as you can see from the above #s even a street car can get more out of it's rear brakes. The only car that really needed the p/v was the 3.2 Carrera and some guys that track those go w/o too, but carefully.

Shamstar

Thanks Bill, very helpful as usual!

jon91581

On a similar note, does anyone know if a 993 rear cross drilled rotor will fit on the 964 rear with the correct spacing? The rotor dimensions seem to be the same, I'm just looking for another alternative to a 968 M030 rear rotor.

Thanks,
Jon

Bill Verburg

964 ans 993 rear rotors are the same size but they are not interchangeable because of the o/s

cobalt

Part number should be

95135204191

If you find a good price let me know I need a set for my C2.

KaiB

PM me, I have a set in good condition which I've held as spares.

These are the 964RS drilled rear rotors.