Proportioning valve question

[Drkuhar]

My 1984 Cutlass sat for 18 years with the back brakes unhooked. There still was a small amount of fluid in the reservoir. I installed the factory rearend from a 1984 Monte Carlo and could not get any fluid or air. Nothing. I have read up about the proportioning valve button and want to know if this is it and does it look out

 

[Drkuhar]

I have no engine, transmission,battery in the car and I believe I have to open the fronts to equalize the pressure before it will move. As of now I could not budge it with my fingers

 

[TexasT]

A clamp might move it but it is probably rusted up inside.
It can be disassembled but for the cost of a newer brass one I'd just replace it. Stopping isn't really something you want to not work. And emergency stops that lockup the rears ain't no fun.

 

[WanaBa442]

Went thru that when we replaced the M/cyl in the Cutlass.
The little black button will "lock out" the part of the system that had no fluid, or pressure.
It should reset when the black cap is pushed in, but as said it's probably rusted in one position as it sat for so long.
Replace it, and all other lines that look suspect.

 

[Drkuhar]

my local napa cannot get me a new proportioning valve but I see quite a few on ebay. Is there any thing I should look for specifically or anything to avoid. I want to be as close to direct bolt in as possible