My proportioning valve gave way and I received the new one today. Like many have stated..."I didn't even know it was there."...until it broke. I got the old one out and am confident I can reinstall the new one. I looked at the fsm and do not know how to adjust the thing. I see there's an adjusting but on the end of the arm.

I'm assuming it hasn't worked for while, in 17 years I've not had to do the back brakes.

So how do I adjust it after bleeding the lines and valve first? Thanks guys, this forum had helped me with a ton of repairs over the years.

 

Yes you will loosen the nuts on the adjusting rod sou you can move the arm up or down on it. Moving it up will allow more brakes, while moving it down will close off flow and result in less brakes. When I put a 2" lift on my 93 pickup i just used the trial and error method until I could feel the rear brakes begin to work again. I'm sure there's a 10 page procedure on it somewhere, but it's been working for me for the last 12 years.

 

Yeah, the fsm looks like it's using weight scales and pressure meters or something, I've never had to muss with so I have no idea what to do with it, other than reinstall it. None of my mechanic friends really knows anything about it either.
i know it's supposed to prevent back brake lockup, but I don't know how to test that either. This thing really is a bit of a mystery. Took 2 weeks just to recieve it from Toyota. Thanks for the help.

 

When I replaced mine a couple years ago on a 92 two wheel drive, all I did was put the new valve body in the same location where the old one was. Then adjusted the #2 shackle to the initial set. It's been fine ever since loaded or empty.

Not saying to do this, or it's the right way. Just saying it worked for me, and saved me a bunch of money in the process doing it myself.

 

Sounds like that's how it's gonna go, trial and error. Any hints on determining if I have too much or too little back brake?

 

I went out on a loose gravel road and just locked em up at about 10-15 mph while watching the rear tire in the side mirror. If the front locked and the rear didn't I adjusted up, if the rear locked before the front I adjusted down. It only took a couple tries before they were pretty much hitting at the same time. I figured that was good enough. Even on pavement I could feel the rear grabbing too hard before I had it adjusted right.

 

Thank you, trial and error it is. Like most things...just do it as best as you can.