g-body C5 master cylinder question?

[white79bu]

I am getting ready to install a set of C5 brakes on my g-body this winter. I am still trying to find out what master cylinder to use? I need one that will work w/rear discs. Also if anyone has a suggestions on a booster to help with vacum would be great. Thanks Andy

[gmachinz]

You'll need to make your own lines/fitting ends but I like to use the mc (1" bore) from a 3rd gen. Camaro w/rear discs. I also use the factory type combo valve as well. The ends are iso-metric and nobody that I know of makes the ends, so you need to hit a boneyard up for the fittings-there are three goofy sizes and two of them are non-existant from aftermarket suppliers. The fittings for the rear (on the combo valve) is something weird like a 10mmx1.75 or something like that. I flare my own lines once I get them bent just right-it's time consuming but it looks great afterwards-and it appears factory to. -Jabin

[Supercharged 86]

I thought the stock masters were 1". For my rear discs I used a B body MC that I think is 1 1/8".

[TPI Monte SS]

I'm also running the B-body master 1 1/8" cylinder. I ordered one spec'd for a '90 Caprice with the 9C1 (cop car) option, and my '88 Monte Carlo brake line fittings worked perfectly; no adapters necessary.

As far as a better booster goes, you should try to find a dual-diaphragm booster from an '87-'88 G-body. If you really need it, the dual-diaphragm booster from an '86-'90 B-body will also fit. I've used one in the past, but I think the G-body dual booster has better pedal feel.