I have a 1991RS with a limited slip rear drum
axle. I have located a 1992 Z28 with a posi rear disk axle. I would like to swap the posi disk axle for the drum axle in my 91 RS.
However someone has already taken the proportioning value out of the 92 Z28. I have
86 Z28 with a four wheel disk proportioning value. Could I use the 86 Z28 value with the
92 Z28 rear in my RS?

Or would it be cheaper to buy a new
91-92 proporting value for 4-wheel disk brakes?

Also can I use my existing rear brake lines on
the Z28 disk brake axle?
(Okay so it was more than one question)

 

I'm not positive that the older pv will work or not performance wise , but i know that it won't have the right fittings the newer cars have this metric bubble flare crap that your older pv doesn't use. Check it out i'm not sure when they changed it all over.

 

You really don't want to use the 86 PV.

It's designed for the older style discs, which were given all sorts of bandaids from the factory (and still didn't work that great).

You definitely need to keep your current master cylinder, and I would try your drum PV. If it provides adequate braking, then don't mess with it.

I do know that 89 and 92 had different PV's (used different threads on the rear brake line). There was a dividing line in there but I can't remember whether it was 91 or 90.