Last year I eventually installed a rear disc setup from Ed Miller. The problem is that the rear brakes perform very poorly and I'm running out of things to try. Ed has suggested that the master cylinder may be the problem which I don't mind replacing if that is the cause, but I don't want to go down the road of replacing parts that don't need replacing. Aftr the brakes and proportioning valve were installed the brakes were fully bled and the guy who did it striped down and cleaned the master cylinder and the performance is still dire. Does anyone have any suggestions? I've heard people talk about bench bleeding the master - under what circumstances must you do this and what is the procedure? I've never heard of this before and not sure if this is an issue with all cars or just the design on ours?

Lots of questions but thanks for any help at all.

Robert

 

Anytime the master cylinder is removed from the car,installing a new one or the fluid gets to low in the reservoir you usually have to do the bench method to get all the air out of it. Did you replace the proportioning valve with a disc proportioning valve, if not that can cause the rear brakes not to function right. Another method is replacing the spring in the drum proportioning valve, haven't tried this before but a lot of people have had success with this.

 

Hi,

I changed the proportioning valve with the new one that came with the kit and at the time that made a slight improvement to the brakes.

I am trying to get hold of one of the stiffer springs but so far I'm not having any luck. If anyone has one they would sell me I'd be grateful.

What is the procedure for bench bleeding the master cylinder?

 

I have a few of these springs I got from grainger left if you want one. $5.00 plus postage which probably won't be much.

 

Here is a website that explains it pretty well. http://www.superchevy.com/technical/.../0509sc_bench/

 

bench bleeding is insanely easy to do.. there are youtube videos out there that show you how to do it.

 

Arod231,

I've sent you a pm regarding the spring!

I'll try the spring and bench bleeding the master and let you know how it goes.

Thanks,

 

The master wasn't bench bled but the guy who bled them used one of those vacume systems that pulls the fluid through from the master. I'm not sure if air could still be traped as a result of this?

How can you tell if the master cylinder is broken and needing replaced?