87 Corvette brake master question

CR67rep · #1 (**permalink**) 03-10-2018, 03:17 PM

Hello all,

As I continue to replace items on my CR in preparation for a hopeful trip to Power Tour this year, I have come to the point where my brake master needs replaced. I have read that the newest recommended set up is to use a 1987 Corvette 4 wheel disc master even when using drums in the rear. I have seen versions with a single reservoir with extension that connects to the front of the cylinder (Centric 13062063) and versions with 2 individual reservoirs (CARDONE 134001). Is there a preference on which to use? My instinct would be to use the one with 2 reservoirs. Also, I read that DV suggested getting a Jegs or similar proportioning valve for the rear brakes, is the idea here to ditch the existing proportioning valve and only adjust the rear feed? Currently using the 9'' front rotors and drums out back, but intend on upgrading to 11'' fronts and possibly go to sn95 rear discs.

331lxstang · #2 (**permalink**) 03-12-2018, 04:21 PM

Just went thru this on my cr roadster, don't waste your time with the Vette mc. I have 4 wheel disc and results were the same with disc/ drum. I converted to manual due to vacuum issues. After I changed the brake pedal ratio and went manual I couldn't get enough brake pressure to lock tires up in emergency. The best ratio I could achieve with stock brake pedal arm was 5:1 after relocating pivot point on pedal assembly. Tried the Vette cylinder, no change whatsoever. Tried adjustable prop valve still no change. Finally realized due to pedal ratio needed smaller bore master cylinder 7/8 bore from wilwood did the trick. It made a massive difference part #260-12900 for those interested.

MaSnaka · #3 (**permalink**) 03-12-2018, 04:40 PM

I switched the 9" pinto brakes for the Wilwood Dynalite 11" discs. Dropped around 30lbs from each wheel. Better braking for sure. Then I put 11" discs on the rear with a wildwood adjustable proportioning valve. I changed the MC to accommodate the rear discs...need a bigger reservoir for those. I used Classic Performance Products 15/16" bore master. No booster. It works well but I did change the pedal ratio for manual too because it was set up for booster pedal ratio. Pics in my gallery.