long story short..i replaced front and rear calipers due to bad seals,abs unit and rotors..but now i cannon get fluid to go to the rear brakes and they are not working..i have tried to bleed them manualy and crisscross pattern and i also tried opening the bleeders and gravity bleed but with no luck..is there a proportioning valve on these blazers? i have a 1998 blzaer 4x4 base...any tips,pics links or help would be greatly appreciated,ive been fighting with this problem for about 2 weeks..and then remembered i joined this forum when i bought the blazer.

 

Quik ?, in what order were the parts replaced? What was bleed first? Did you bleed from right rear to left rear to right front to left front??

 

try bleeding the brakes with the ignition key on. reason i say this is because it will cycle the abs module and do a self test may help you out, and as stated above you should start bleeding rr,lr,rf,lf. also one thing you should check is the bleeders pull them out and make sure the holes are drilled in them for the fluid to exit. ive seen many times where you get a new caliper set and the bleeds havent been drilled. now every time i replace calipers i check to make sure the bleeders are good before leaving the parts store.

 

It's almost certainly the proportioning valve. Esp if you had a gross leak in the rear system.

But you cant find it, and no one can tell you how to do it.. blame GM.

Long story short.. and I did a lot of searching on this, it's what I do.. the best answer is to take it to a shop that has the Tech II scan tool. And make sure they DO know how to reset the prop valve on GM with ABS.
I think I could do it without but it would be a whole afternoon project

 

thats what im affraid of prettyfrog, ive been reading also and it seems that the scan thing is the only way togo..and to the other, i cannont bleed the rearright 1st because i cannot get fluid to the rear at all..i will try bleeding with the iginition on and see if it will happen to throw any fluid to the rears..money is a big crunch rite now or id have taken this in long ago,but i fear its time..also ive read that unplugging the battery for awhile can reset the valve, is this true? i figure i might as well try...

 

if you let the master go dry try bleeding it at the master first

 

no i never let it get close to dry or even low..i tried resetting the ecu today with no luck...

 

you can try bleeding the brakes with car running to use the booster to mabe switch the valve over. ive never ran into this problem and i leave cars on the hoist with the brake system pulled apart over night. worth a shot anyways. what i would suggest is get a jar and a hose that will fit tightly over the bleeder put it into the jar with some brake fluid and than do what i said above, cheap 1-man brake bleeder.

 

Had the same problem diagnosing dragging rear brakes, after replacing rear calipers I could not get the fluid to go to the rear and very little to the front.

I decided the master cylinder must be bad and replaced it, still no fluid to rear. I eventually loosened the MC from the booster and it would bleed properly. My booster has a plastic pusher that contacts the MC so no adjustment there. I decided to shim the MC with a couple thin washers and it works perfect now, can bleed and no more dragging brakes.

I have told myself I will look for the adjustment and do it right, someday.

 

This is good info. OP should try that.

There is no adjustment. What's happened -since you had the same prob. with two MC's- is probably your booster has deformed.

Recently had a couple cases on here where the front brakes dragged. Yet they could be bled. MC fixed them.

Weird. See my sig.. it does apply, sorta. Except making it idiot proof means more people feel like idiots.