s10 rear brakes not working

[rudytoot23]

Hi I have a 1997 S10 ZR2 disc brakes on the front and drum in the rear. My problem is that it has no (or very very little) rear brakes. The front brakes seem to work good. I have changed the master cylinder and bleed the brakes and still the results are the same. I'm lost of what to try next. Can anyone help? Thanks Dave

[movin2stereo]

ZR2s have dics all the way around.Anyway,the front brakes do most of the braking and what you have is probally normal.

[rlith]

No, this is not good... Your rear brakes need adjusted... See my post regarding this issue here... You have to much braking going on upfront... You should be running 60/40

http://forum.zr2.com/ubb/noncgi/ulti...=003445#000000

[dmbrisket 51]

nice post rlith

[rlith]

Originally Posted by movin2stereo

ZR2s have dics all the way around.Anyway,the front brakes do most of the braking and what you have is probally normal.

Older zr2's had drums.

[rudytoot23]

I tried adjusting the rear brakes and I got them very tight where the rear drums would barely spin. Still I had no brakes. It's bad enough that when I am on ice or snow and I have the brakes fully down that the idle of the truck will spin the rear tires. I've heard that the aluminum master cylinders aren't any good and they let oil bypass. I've had 2 on it with the same result. Maybe I ran into 2 bad ones, I don't know.

[rlith]

Hmm, if you've now adjusted the rear brakes and you;ve bled the rear brakes properly...(Gravity bleed or vaccum pump) and they still aren't grabbing, that leaves 2 things. Either A, one of your brake cylinders is bad, or B, you need a new proportioning valve. You should have about 600-700 psi at the rear brakes.

[rudytoot23]

if one of the brake cylinders are bad will that make both rear brakes not work properly?

[rlith]

yes, because you have a single line feeding both brakes

[higher miles]

i had a similar problem on my s-10.the rear was actually locking up when stopping.i changed the master cylinders and threw in some new shoes and power bled the system.it is working great now.rear wheel cylinders are pretty cheap at kragen(20 bucks each)too.

[Fireplug]

It does NOT sound like you have 2 bad rear wheel cylinders.
It sounds like a low pressure bad proportioning valve or cloged brake line leading to the rear.
1 bad rear wheel cylinder will not cause the other 1 not to work. The main brake line goes back to the rear axel then the line splits and goes to each rear wheel cylinder. What you have to do is get you hands on a brake pressure test gauge and start at the rear wheel cylinders and keep checking for the correct pressure and work your way back to the master cylinder.
The rear rubber brake hoses have and will fail and plug up and not let the correct fluid pressure to the cylinders.

[movin2stereo]

Originally Posted by Fireplug

It does NOT sound like you have 2 bad rear wheel cylinders.
It sounds like a low pressure bad proportioning valve or cloged brake line leading to the rear.
1 bad rear wheel cylinder will not cause the other 1 not to work. The main brake line goes back to the rear axel then the line splits and goes to each rear wheel cylinder. What you have to do is get you hands on a brake pressure test gauge and start at the rear wheel cylinders and keep checking for the correct pressure and work your way back to the master cylinder.
The rear rubber brake hoses have and will fail and plug up and not let the correct fluid pressure to the cylinders.

Agreed,don't go by the looks of a brake hose.