brake proportioning valve

ok this is not for my blazer but i cannot get anyone to answer in nthe c/k truck forum and i know it works the same..

so here goes.
i had a brake line bust and lost all fluid to the rear brakes .. and it set the proportioning valve so no fluid would go to the back brakes.. well i replaced the line and blead the front and are working fine but i cannot get any fluid at all to go to the back to bleed them.. i can see that the proportioning valve is not centered anymore if i take off the rubber boot covers.

how is it done to get this thing recentered...

On my older Suburban you simply pushed the end with your finger to recenter located under the radiator. They had a tool to hold it while bleeding the brakes but if you pushed slowly it stayed centered. Not sure if the same as yours.

the front of the valve is showing the pin and it comes out a bit when brakes are applied.. but i cannot see the rear but if i stick a small allen head tool in the hole it lets the allen head go all the way in.. so i know the pin is not visable. i have tried everything to get this recentered. there is a trick to this and i dont know what it is?

i am getting know fluid to the rears at all

It should be centered only. Never said what year but if older (line broke so probably is) then replace both sides hoses and the wheel cylinders - are the bleed screws even opening and not full of crap - that would be my guess. I would change the prop valve if old too because it will not work correctly when old - has a booted piston like a mater cyl in it - crap raised hell in there. Flush the fronts too till new fluid runs clean.

the bleeders are clean and the proportioning valve is off centered because of no fluid to the rear brakes and the brake light is on..
front have been bled and are working fine...

its just the propoertioning valve has move out of sync when the fluid ran dry in the fill reservoir, and i cannot get it back cenetred, dont know how its done..

1989 chevy

the bleeders are clean and the proportioning valve is off centered because of no fluid to the rear brakes and the brake light is on..
front have been bled and are working fine...

its just the propoertioning valve has move out of sync when the fluid ran dry in the fill reservoir, and i cannot get it back cenetred, dont know how its done..

1989 chevy

If the pin goes in it is hard to pull back out. If you can not pull it back out open bleeders on front end and see if pumpimg master cylinder will pop it back.
Also a pressure bleeder will sometimes push the pin back out.
If not as said you may have to replace the valve.
MT