I'm planning on pulling my single cup resevoir off my brake master cyl tomorrow (weather permitting) and installing 2 new cups.

I notice that the single cup (with fitting to 2nd master hole) is REPCO and the 2 cups are PBR.

question:

is there ANY difference or anything to watch out for in the way the cups seat in the master cyl grommets? Both are the exact same fit correct? I want to make damn sure because my single is cracked and it WILL come off in pieces...so I'll be committed at that point.

 

its an upgrade that I've read about here, the only issue Ive seen is the disintegration of the old plastic, I'll try to find the thread
here's one
http://forums.corvetteforum.com/c4-t...aster+cylinder

 

Interesting, my 84 came with dual reservoirs. I thought the general always made improvements as the years went on. Wonder why they went with the single. The obvious answer is cost I guess.

 

It was a cost cutting exercise
There is no way one reservoir is an improvement except to the makers bottom line. Note the dual piston brakes on 88-96 vettes (as the J55 with 13 inch discs on my 85 i upgraded to) can almost drain the front brake reservoir from new pads to needing replacement brake pads not a good thing if you are down on front and rears and have a leak develop. at least with a dual reservoir if you lost all your front or rear brake fluid the front or rear brakes would still work

The grommets to fit the reservoirs should be available somewhere, anyway don't the single reservoir master cylinders have a small tube going to the front where the other reservoir would be?

 

grommets are available at the venders, napa, rockauto and others, hope this helps

 

The single has a divider between the front and rear parts. A leak in one end won't drain the other end.

Chuck

 

ok, cool.

I wanted to be certain that this was the same system (master cyl body) with the cups being the only real difference...

The single cup has a divider in the bottom so only the upper portion of the resevoir fills the transfer tube to the forward master cyl port. As long as there is 3/4" of fluid the divider is covered and the brakes will work...the rest of the cup is just resevoir.
It was due anyway...Soon I'll be installing my big brakes (13") with the 2 piston calipers and those will suck the single cup dry in one step if a leak were to develope...so I was planning to install the 2 cup system anyway....it just cracked and started leaking the fluid everywhere so its coming a few weeks early...like an early Christmas. <- most optimistic thing I've come up with in 20 yrs...

BTW...
anyone that has a similar issue, I bandaged the cracked tube with a small fuel line clamp to hold it together and keep it on the fitting until I could get replacement cups. The fitting in the forward hole also started to leak (cracked)so it got a bigger hose clamp around its round body so it would not come apart...the plastic is just fatigued and cracking everywhere from age and the very harsh ride that I have in this particular car. I did not want to risk pulling those cracked parts out until I knew for sure that these new cups worked. Already have the grommets..just need to install. Tomorrow is 'car day' if the rain stops..lots of projects for the 'ol vette.
Thanks for the replys, guys