Thread: Serious brake problems

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My braking system is all messed up. I need help finding what parts I need to buy.

This is in a '90 S-10 Blazer with a 454 big block

I have a stock factory master cylinder with a 1" bore and the correct pedal ratio. I am not using a combination valve. The front line(rear of MC) goes to a tee and out to SSBC Force 10 calipers sqeezing factory rotors. The rear line(front of MC) goes through a Wilwood adjustable prop valve to Ford 11X2 drums.

The problems are numerous. The rear brakes do not work at all. I've been driving it for a while and the shoes look brand new. The front brakes do not work very well either, but the pedal is extremely firm. The front brakes sometimes seize up, especially the front right. Sometimes the pedal will get so hard I can't even push it and I can hear the fluid boiling in the calipers.

I'd like to switch back to a power setup if a manual can't cut the mustard, but am unsure of the idle vacuum I will have with my new engine combo. What do you guys think? 454 BBC 9.5:1CR w/ Victor Jr intake and Voodoo 282/290 adv dur, 231/239 @ .050 dur, .600/.600 lift on 110LSA. I just want to fix this once and for all. I think a medium sized booster will fit, something around 8".

HELP!!!!

Have you dialed in more rear brake pressure with the proportioning valve??? What was the result.???

Are your headers close to the master cylinder?? I have seen heat from the headers cause the brake fluid to boil.

Is your right front caliper possibly hanging up???

You will probably be a bit short on vacuum with that much cam. A vacuum canister would help. I'm sure the motor guys will be along with more advice on that.

Actually I removed the adjustable prop valve once to see if the rears would lock up and I still had nothing from them and a very firm pedal. I'm thinking that the residual valve was in the combination valve and I am not having the right preload on the shoes.

And you are right, there is no residual valve in the master cylinder of newer cars. You need to put the proportioning/metering valve back in the system. but still if your master cylinder is working you should have rear breaks if the line goes straight from the MC to the rear breaks. Adjustable prop valve and add residual valve should work. like Dave says sounds like you have a caliper sticking and no vac. at the booster also.

http://www.ecihotrodbrakes.com/brake_facts.html

I had a similar problem on my 71 C10 I found I had a bad hose on the right front and a cloged line to the rear brakes. Beleave me I thought I was going nuts.In desperation I pulled the brake line off one side in the rear and hit the pedal. After all what could it hurt. NO FLUID so I pulled off the other side no fluid there either. The line from the MC to the rear was blocked I dont know where or how but after changing it I had brakes. I had a firm pedal all the time but no brakes left front was the only thing working. Good luck
Charlie