Rear Proportioning Valve Comments

[HOrnbrod]

Actually my first contact with a rear brake proportioning valve was on a Chevy 1 Ton that I owned. It seemed like a great idea to me - the more weight you put in the bed, the better the brakes. It still seems like a good idea - if it works properly.

 

It is a good idea, but you're right: if it works properly. Trouble is in most of our old MJ's the load sensing valve is either rusted inop, or is broke internally. No parts or replacements are available anymore, so they get ripped out and bypassed. Toyota and other P/U manufacturers use them too, and swapping them out is easily done. I was coming back from TN last weekend with a crapload of stuff in the back, and had to slam on the brakes to avoid some fool on the interstate, and there was a positive noticable difference in the front-to-rear brake proportioning than when unloaded.

[87mjdriver]

what about replacing the self proportioner witrh a knob adjusted one?

allen

[HOrnbrod]

what about replacing the self proportioner witrh a knob adjusted one?

allen

 

Like this? http://toyota.off-road.com/toyota/artic ... ?id=186295

[Eagle]

Summit Racing has a Wilwood adjustable proportioning valve. I know people who have used it to restore rear braking in XJs. It should work fine in an MJ, but it would require resetting when you load the bed down.

 

Chrysler has a similar (or the same?) thing in the MOPAR Performance Catalog.

[87mjdriver]

thats fine I don't carry many loads in the truck anyway. what size fittings would I need to get.

[JeeperjohnfromPA]

OK here is some light shed on this, No answers, just some info.

 

I was at a junkyard the otherday, they had a 1986 MJ in there, but it was a 2wd model, not a 4x4 like mine.

Anyhow it had the little rod that connects the axle to the brake proportioning valve.

Now the 87 MJ in my driveway is missing that little part, so I grabbed it.

As I was removing it, I thought that the part where it hooks up to the axle looked different then what was on mine, so I grabbed that too.

 

THEY ARE DIFFERENT.

The little part that mounts on the axle is different, and this would throw everything outa wack.

I'll get some pictures up here as soon as I can figure out where my old digital camera is.

[HOrnbrod]

OK here is some light shed on this, No answers, just some info.

 

I was at a junkyard the otherday, they had a 1986 MJ in there, but it was a 2wd model, not a 4x4 like mine.

Anyhow it had the little rod that connects the axle to the brake proportioning valve.

Now the 87 MJ in my driveway is missing that little part, so I grabbed it.

As I was removing it, I thought that the part where it hooks up to the axle looked different then what was on mine, so I grabbed that too.

 

THEY ARE DIFFERENT.

The little part that mounts on the axle is different, and this would throw everything outa wack.

I'll get some pictures up here as soon as I can figure out where my old digital camera is.

 

You mean the piece that bolts onto the diff cover? Maybe the diffs were different, like one was a D35, the other a D44, or even an AMC20?

[JeeperjohnfromPA]

I'm going back there this Friday. I hope the comanche is still there . I'll double check which axle it had, looked like what was in mine, but I realy didn't look to closely.