XJ proportioning valve??

I put a XJ proportioning valve on the MJ and have little to no brakes. I hooked the lines in as they were in the MJ, but have no pedal and not much pressure at all 4 bleaders no matter how much I blead the system. I am thinking air may have got into the master but wanted to check if anyone had any problems with the XJ proportioning valve first.

Charles

did you cross the lines when you put it in? or does it leak?

No leaks, no crossed lines.

Charles

i got air in my master cylinder. once i knew that i could of, i just kept bleeding them. takes a while for the air to work itself out.

No leaks, no crossed lines.

 

Charles

Unfortunately, you probably DO have a crossed line.

The MJ has two lines to the rear, where the XJ has only one. How did you deal with that? Here's the issue:

The XJ combo valve has the line feeding the rear coming out of the fitting at the forward end of the block on the bottom. The XJ combo valve has no fitting in the "nose" -- only the plug for the proportioning piston rod.

The MJ has two lines to the rear, one for the normal brakes that runs through the rear proportioning valve, and one that bypasses the rear proportioning valve but is actuated only when the front brake circuit loses pressure. BUT ... the bypass line, which normally is not pressurized, is the one at the bottom of the block. The line coming out of the "nose" of the block is the one that feeds the rear brakes under normal conditions. If you blocked off the line that was in the "nose" and connected up only the line to the forward, bottom fitting on the block ... you effectively disconnected your rear brakes.

When I went with the 8.8 in the back I dumped the valve in the back and the return line. Both lines from the master hooks up in the same set up as the old MJ, The out put lines are as followes. F/R out back end of P valve, L/F out of bottom rear output, and rear out of bottom front output.

Charles

i'm going to look at my valve tomorrow,curious now how it hooks up and where they all go. :chillin:

Okay, then the next question is did you open up the XJ combo valve and clean all to gunk out of the proportioning pistol chamber before you installed it in the MJ?

No, went from the JY XJ to the MJ.

Charles

No, went from the JY XJ to the MJ.

 

Charles

In that case, I'd suggest pulling the plug in the "nose" to remove the piston and spring, and clean out all the crud that's likely in there. BE CAREFUL -- the pring is under a LOT of compression, and if you let it go that cap will fly out pretty hard. There's a rubber O-ring toward the back of the piston. You need to ensure that's clean, and the recess it fits into is clean. Keep the O-ring if you want the thing to proportion. If you remove the O-ring and spring, and assemble with the pistol pushed all the way forward into the plug, you'll have full braking power to the rear wheels all the time.

Thanks,

I will give it a try.

Charles

Wow,

I am glad I looked into this topic again. I researched it once before and thought the fitting in the nose was the one not used.

I was about to plug the fitting in the nose of the prop valve, and just use the line from the front/bottom for rear brakes (while doing away with the rear prop valve).

So, technically, one should be able to plug the front/bottom fitting in the front prop valve and just use the line coming from the nose of the prop valve for full braking in the rear, correct???

Thanks,

Andy

Andy, are you talking about using an MJ valve or an XJ valve?

This is my plugged MJ combo valve. Notice I originally tried to use the wrong port. :oops:

So, technically, one should be able to plug the front/bottom fitting in the front prop valve and just use the line coming from the nose of the prop valve for full braking in the rear, correct???

Correct. That's what I'll be doing on the red wreck.

Andy, are you talking about using an MJ valve or an XJ valve?

This is my plugged MJ combo valve. Notice I originally tried to use the wrong port. :oops:

 

 

Yes, I am sticking with the MJ prop valve. I think I am in good shape for using the factory line. I was able to loosen the line that goes directly to the rear prop valve (from the front prop valve). I traced it out and think I have it right (my 3yr old was holding the flashlight :roll: ) but the line that goes directly to the rear prop valve ties into the nose of the front prop valve, correct??

Any trouble finding the right size plug for the front/bottom line on the front prop valve?

combination valve

combo valve

proportioning valve

(I typed those other names just for the search feature...)

Thanks gents (and Eagle :brows: :D )!!

Andy

Yes, I am sticking with the MJ prop valve. I think I am in good shape for using the factory line. I was able to loosen the line that goes directly to the rear prop valve (from the front prop valve). I traced it out and think I have it right (my 3yr old was holding the flashlight :roll: ) but the line that goes directly to the rear prop valve ties into the nose of the front prop valve, correct??

 

Any trouble finding the right size plug for the front/bottom line on the front prop valve?

 

combination valve

combo valve

proportioning valve

(I typed those other names just for the search feature...)

 

Thanks gents (and Eagle :brows: :D )!!

 

Andy

You're saying you'll leave the line in place from the "nose" of the combo valve body, disconnect it from the rear proportioning valve, and then connect that end to the hose on the rear axle? Yes, that'll do it.

For the plug in the "other" rear outlet at the bottom of the valve body, get the shortest/cheapest 1/2" x 20 bolt you can find. Cut the threaded portion down to 1/4" in length, put an O-ring on it, and you have a plug.

You're saying you'll leave the line in place from the "nose" of the combo valve body, disconnect it from the rear proportioning valve, and then connect that end to the hose on the rear axle? Yes, that'll do it.

Yes, thats what I am saying. The line is in good shape, so I see no reason to mess with it. Excellent, thanks!!

For the plug in the "other" rear outlet at the bottom of the valve body, get the shortest/cheapest 1/2" x 20 bolt you can find. Cut the threaded portion down to 1/4" in length, put an O-ring on it, and you have a plug.

A 1/2 x 20 bolt? hmmm...that sounds a little big to me but I am sure your correct.....thanks again!!

I'll have to get some pics up here soon, but the MJ is growing up. Its not my fault though, I was instructed by Leah (my wife) to build it, she is making me do it!!! She wants a truck to do "light" trails with. She enjoys rock crawling as much as I do. I fell off the wagon a little though, (it will have 6.5" of lift, 33's 4.56's, locked front/rear :roll: ) but it should be able to handle light trails NO PROBLEM ;) :D What can I say, I had lots of extra parts from various builds of my XJ. Don't worry Eagle, as long as she stays behind the wheel the suspension/drivetrain will remain the only thing modified.

Andy

I used a brass pipe plug on mine. I had the valve off, and took it with me to Advance Auto and rooted thru their fittings cabinet until I found one that fit :D

1/2" does sound big to me....I seem to remember it being 5/16 or 3/8.

(it was a long time ago :oops: )

Jeff

I went to the auto parts store with the fitting that came out of the hole and bought a plug. :dunno: It's less creative, but it was simple enough. :D

I took a look at my XJ prop valve I had laying around...turns out the plug in the back end is the right size. It had a little cup on the end that needed cut off, but it will work perfectly. Even had an o-ring on it already.

It is 1/2 x 20, I sized it up w/a standard (coarse thread) 1/2" bolt. Shoulda known better than to doubt the Eagle, it just sounded big....

Thanks again,

A.

I cut the line, took the fitting off and spot welded it up then stuck it back in.

I cut the line, took the fitting off and spot welded it up then stuck it back in.

Now THAT's redneck engineering.

who has the pics of the different prop valves, XJ, MJ and etc on which one to plug? I had it the other day but forgot which one again. Wanting to install the XJ valve in the MJ and loose the MJ valve(s)

http://comancheclub.com/forums/viewtopic.php?t=4968&highlight=prop+valve

yeah thanks, I found it later, if you see the last post in the link. :yes: but good to have it here though for someone searching for the same.

Side note, I have the WJ set up with XJ valve, pulled the rubber out of the valve, running dual piston ford calipers in front and chevy fron calipers in the rear with my 44/60 combo. everything was a direct bolt in, no grinding no anything, Used a ford brake light switch. post a pic in a bit. I am very happy with the results, pedal feels great and I stop like a brand new truck. :D