This may help... From:
https://blazerforum.com/forum/genera...o-fluid-47695/

 

Where is the proportioning valve located

 

Noticed when pumping them up the fluid doesn't go down very fast if at all......maybe master cylinder

 

on the firewall drv side i think just follow the brake lines from the master you'll find it. recently ive been getting calipers in that dont have the bleeder holes drilled out so you might also want to check that too. also to get fluid going just open the bleeder and let it gravity bleed for 10-15mins. only open one bleeder at a time and do this.

 

Someone told me that if the pedal has no pressure at all to check the master because this fluid was REALLY burnt....I don't think I have fluid to front either

 

Will try to reset pro valve........ if that don't do it what next......just had brakes less than a week ago

 

WTH? Are you saying that now you dont have front brakes?

Here's a tip.. when you get some info, use that info to broaden your scope and research for yourself instead of expecting folks to lead you down the garden path to success.


Yes.. Google is a GOOD thing. Or Bing, whatever. NEVER take one person's word -even mine- for anything, back it up with your own knowledge seeking to find consensus.
what does a proportioning valve do

Reading some of those hits, you learn there are TWO functions for it. You are a 'victim' of the second and most important one.

The problem is LIKELY in your prop valve or whatever.. I doubt it is a stopper screw installed by a prev owner but who knows.

 

Everything I've read points to pro valve....can I did thus one or do I buy a new one.....is it an easy fix

 

Can I fix this one or buy a new one

 

Well I got confused.. somewhere we transitioned from front brakes worked but nothing to rear to no brakes working

Actually if your pedal is going to the floor and it wont pump up, that points to a bad master cylinder. In fact even if it will pump up but left alone you have to start over.

Otherwise, if you have ABS.. there's air in there. Guess I would recommend hauling it in to a proper independent brake shop.

Here's another possibility for some: The booster push pin may be adjusted wrong for the particular master cylinder. I had some vague memories stirring from long ago when my MC wasnt acting right:

http://www.classicperform.com/TechBo...ot.htm#pushrod