Wiki Home \ rear proportioning valve removal...

rear proportioning valve removal...

Last Updated: Feb 22, 2015
View Photos is what I did to remove the rear proportioning valve on my 91 2wd extra-cab truck. Most of you know that the late models...88 & lower came with a standard proportioning valve, but it was located under the master cylinder. So unless your planning to haul crap or whatever in the rear then you wont need it. The only part I bought was a $1.00 1/8 npt hex head plug from Advance Auto Parts. Youll have to bleed the brakes again so be sure to have some brake fluid as well. So on to the pics...

Here is what it looked like on the truck...

thread post photo

thread post photo

thread post photo

This the t-unit located on the passenger side frame rail near the front tire...
thread post photo

I removed the high pressure line from the t-fitten & capped it with the 1/8 hex plug. If you notice that there are 2 lines running to the rear valve, your plugging the high pressure side & keeping the low pressure side. The high pressure is for the front brakes just incase you were wondering....-
thread post photo

So I got the high pressure line plugged & then you can follow both lines to the
rear & unhook the high pressure first, then take it off like I did. After you get the high pressure line removed or pulled out of place unhook the low pressure line from the rear valve & hook it to the rubber brake hose that is hooked the the t-fitten on the rear axle pictured below...
thread post photo

thread post photo

So this is what I did to remove the rear valve...Ive bleed the brakes & have a firm brake pedal. I have not driven the truck yet, but will be doing so to finish the bag job first lol. I have done this on a buddys truck & his 93 model Toyota is doing just fine. Here is an exact quote off from a buddy of mine who has done several of these trucks without any problems as well too.

"Here's what you do. Since the valve takes the greater pressure from the front brake circut and over-powers the weaker rear circut, just cap the line at the tee. The tee is located on the pass side front on the frame about where the firewall comes down. It's a 1/4 or 1/8" npt plug is all you need. You can then just trace the now unused brake line back to the valve and remove all of it. It cleans the rear up quite nice IMO.
When the truck is unloaded, the valve closes off the higher pressures of the front brake circut. Only using the low press circut off the master cyl. When there is a larger load (bricks, fridge, illegals) the rear tires can accept more braking force without locking up. Since most of us dont put heavy loads in the beds anymore, you dont have to fell bad about taking it off."


Created By: smctoy

Page 1 of 1
mdevaneydesign avatar
mdevaneydesign   +1y
this is extremely helpful seeing as a little over a week ago when I was under my truck I was wondering what the hell you did with that mess when you bag the rear haha.
smctoy avatar
smctoy   +1y
I also wanted to post this thread off covers this same topic & I wanted everyone see to read/see the options for this mod.

Page 1 of 1