86 MJ Proportioning valve Q's

Working on a buddy's MJ and noticed that there is a bracket that mounts from a proportioning valve "thingy" to the diff cover via a little lever.
After a little looking in his owners manual, we learned that it is used to sense load in the bed and adjust braking accordingly.

We removed the bracket, and noticed that the lever moves very freely. He has always had poor braking, but I think that this thing has something to do with it.

Does anyone know what this thing is, and what you can do to check/rebuild/repair it? He'd like to keep it if necessary.

John

It's a height-sensing proportioning valve that adjusts brake bias (F to R) based on load in the bed. IMHO, it really has no effect on the brake system in my MJ. Some MJ owners have it disconnected and it doesn't seem to affect anything either better or worse.
I suppose you could pull it off and clean/service it, but am not sure if it would be worth it. I wouldn't even want to guess how much the dealer would want for a new one, let alone if there were any available in inventory....
Maybe Eagle might have some insight..mine is there, but who knows if it is doing what it is supposed to???
Jeff

I replaced mine with a T-fitting... apparently I had no rear braking prior, according to the NJ DMV inspection braking test. Once I got fluid to the rear brakes, the rusted lines burst and I had to replace them as well. But now I can lock up the rear wheels as long as the drums are properly adjusted.

The only '86 MJ I have in "the fleet" doesn't have that valve. I always thought it was added in model year 1987. I have no idea how to repair it. The FSM doesn't address that, it says replace. There is an rather involved procedure for adjusting it, but off the record I'm considering removing it on the ones I have. It has been disconnected on the '88 with the lift (no, Mr. DMV inspector, I didn't do it, the previous owner did it). It's wire-tied in a straight horizontal position and the MJ has better rear brakes than the '88 XJ, which of coirse doesn't have the fool thing at all.

Lawn 'Cher left the brake return line in his circuit somehow, but if I were to remove the proportioning valve I would also replace the front combination valve with one out of an XJ and eliminate that extra line that nobody can explain.

My intent is to eventually do precisely that, replace the combo valve with an XJ unit and eliminate the return line. Is the work at the front end fairly straight forward? I've never taken that system apart before.

I don't recommend touching the front proportining valve unless you reeeeally have to. What a pain in the butt! I had to with my axle conversion because I had to replace all of the lines. (I only ran a single new line going to the back and then capped the return hole.) I moved the whole front valve assembly forward so it's easier to work on. (See my pics at the picturetrail addy below. They're in the "Synthesis" folder) Before all this conversion stuff, I just tied the rear valve arm up so that it was parallel with the ground (simulating an empty bed) or you could move it up higher if you want more pressure going to the back. If you have braking problems, it's best to check the condition of the rest of the system too. Both of my trucks have non-functional valves and I've experienced no problems.
Jeep on!
--Pete