cshuman

I've seen some post on using a 4th generation MC on a C4. I've got a 91 that I installed Wilwoods front and rear and need to go to an MC with a larger bore. For those that have used this MC does it line up with the stock brake lines or is there some modification?


Or is there another unit that will do the same thing that will line up with the stock lines?

WVZR-1

No the ports are different sizes and I believe the "spread" of the mounting to the booster is different also. The "spread" dimension difference I don't recall but the ports "best of recollection" C4 are frnt M10 X 1, rr M12 x 1 and the later F-body is frnt M12 x 1, rr M11 x 1.5 maybe. You would be gaining 1/8" piston diameter I believe.

cshuman

I saw another post for a unit that Napa has that some people have used. Does anyone know if it is a direct fit? See below

Myself and another forum member are using this MC with Wilwood
6 Piston GN caliper:
NAPA TRUSTOP 10-2684 Actual bore size is 1-1/16" but works like a charm.

WVZR-1

That's 1 1/4, 1/2-20 & 9/16-18 ports for a later GM truck with hydro-boost I believe.

cshuman

if you would please explain the numbers above.

Thanks

WVZR-1

1 1/4 - piston, 1/2-20 threads front port and 9/16-18 threads rear port. The mounting to the booster would be different also.

cshuman

So they must of made adapters for the lines and also modified the booster mounting to use this MC.

-=Jeff=-

in 92+ GM went to a slightly larger bore Master cylinder in the Corvette than your 91. That is a direct bolt in. I actually have one for my 90 (from a 94 I think) I am going to use.

Also the Brake pedal pivot point changed too (I think in 92) you could replace the mount and pedal as well if you are really motivated.. I have 6 piston Wilwoods on the front of my car, I think stepping up to the 94 Master will be all I need

EDIT:

for the 4th Gen f-body cylinder, you will need different fittings for the brake lines at the master, also you will need a 3/16" spacer on the mount as well. I had the 4th gen f-body on my 89 corvette, worked well

cshuman

Thanks Jeff, it looks like 7/8" bore for 91 and 15/16" for 92 up.