Proportioning Valve only connected to front brakes

CJocho

CJ-8 Member
CJ-8.com Member
City
CHICAGO
State
Il
I'm working on taking the Postal for a test drive and had an interesting discussion with my neighbor regarding the brakes. As is, I've only run a new hardline from the rear resevoir of the master cylinder to the front of the proportioning valve, and then new hardlines from the proportioning valve to the front disc brakes. The master cyliner only has brake fluid in the rear resevoir. The front resevoir of the master cylinder has been left empty as I have not yet run new brake lines to the rear.

In my discussion with my neighbor, I suggested simply bleeding the front brakes as is and seeing what kind of stopping power I get with only the front brakes. My neighbor looked at me cross-eyed and seemed to think I may have a problem bleeding the brakes without having the entire setup. After looking into it, it appears that the proportioning valve doesn't require pressure in both sides when bleeding as a bleeder tool is placed in the center of the valve blocking the piston from moving. Have I understood the mechanics of this part of the proportioning valve correctly? Also, does anyone foresee any problem with a test drive on an empty road with just the front brakes for stopping power?
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
If you don’t block off the valve it will slide off center and require fixing.

Also, the piston in the master needs the fluid for lubricating the seals. Without some fluid you might tear a seal and require a full rebuild.

It can be done, but that would be a “Roadkill Garage” type move.
 

CJocho

CJ-8 Member
CJ-8.com Member
City
CHICAGO
State
Il
Thanks for the advice ag4ever. I went ahead and ran hardlines to the rear wheels per your insight. Thanks for your help.
 
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