The Stovebolt Site Forums The Shop Area Engine Shop single brake cylinder FAILED !

Took my just finished 40' chev half ton out for it's second ride. Brake peddle went the floor! Had the master clinder "rebuilt" by an "expert" not long ago.It lasted about 5 miles. Fortunately, I was going slow on a back road checking everything out.No accident. That truck won't move til it has a dual master on it. The rebuilt 261 runs GREAT tho.Be careful out there.

It's good you're OK!

I daily-drove my '48 for 10 years with a single reservoir MC. The MC outlet only needed one line but it had a tee fitting there. One of the branches had copper tubing that was crimped with a pair of pliers. There were also pipe fitting unions in the system. I'm sure glad that I now have a dual reservoir MC with all new lines and double flared fittings.

Did you replace with a dual master in the stock location? If so, was that an aftermarket or is there a junkyard replacement that can be made to work. I have been driving my 48 daily with a single for 6 months and I have read many posts talking about the singles failure, but no idea what they used to replace them with. Thanks!!

Am lookin into the problem now with a guy who's done many dual masters on old trucks. Will give a full report soon as I'm sure my info is CORRECT.

The original idea of a dual master cylinder is to improve safety. I know, duh. But wait, many brake failures are from other causes than a bad MC. A leak anywhere else in the system can put your pedal on the floor with no stopping power. Rotten brake lines and hoses, bad wheel cylinders and worn out shoes and drums probably cause more brake failures than do bad MC. I agree with Ralphy, it warrants a thorough investigation of the cause. A dual master alone may not fix it. Good luck.

thanks guys. ALL the brake system ,except the peddle,is new except the master cyl which is rebuilt.Brakes are kinda important(which is why I posted my brake failure)so I took the truck to a old,experienced brake shop(owner has a 40's panel truck).He confirmed my view that it IS the single master that failed. Will post the problem as soon as I can do it accurately. I'm kinda new to this stuff.

A good search here should net a lot of posts and pictures on this topic. I went with the '69 Mustang front disc model, even though I'm using it for four wheel drum right now. I got my bracket from ECI, but you need to verify some applications as some tranny linkages are very close by. Should be no problem if you have a four speed, three on tree and hydramatics need a close look, or you may have to modify or clone a special bracket.
The MC has a pedal rod with a big eye on the end. That will need to be cut off, and the rod should be ground down so you can run a thread onto it, for a rod coupling in some cases or a heim joint in others.
Stovebolter Bill Miles graciously provided some excellent photos of his installation on a '53 gmc hydramatic truck. Look for his web site for for information.

I'm new to this site and this is my first forum response.What I did on my '48 4400 to make my brakes more safe was to install a double line master for a '66 Pontiac Catalina. It is for a 4 wheel drum brake system which doesn't require a proportioning valve. Also, the truck has a V-8 in it and the left exhaust pipe heats up the master, making it neccassary for a heat shield. On the other hand, I've been driving my '64 for 3 years with out any problems. ood luck with your brake set-up!

Thanks ALL! 48bigtrucks, howdy 'n welcome . I'm pretty new here too. We bled my brakes and they're working fine now. I don't trust them tho and will follow advice from this thread and my other one"Brake cylinder failed,part2"(or something like that).Tomorrow I'm gonna tighten every connection on the whole system. I'm looking into a dual master too. Your experience is interesting 'n I'll check it out. Thanks ALL,again. jim