MJ to XJ prop valve

[wooky48]

did you hear backfrom them at all?

 

They pretty much ignored the fact that the part made wrong adn just said due to the age of the vehicle there was nothing they could do.

 

They completely missed the fact that i was pointing out a potentially dangerous error on their part and that I in no way ever mentioned anything about them fixing my valve.

 

Sounds like they are sidestepping a potential recall issue due to the bottom line and not worried about the safety of those still on the road, IMHO.

 

I'm going to have to study whats here and see if I can finger out why I only have rear brakes, I didn't know about the height/weight sensor rod and will have to see if mine still has it and if it's hooked up.

[Andy in Pa]

I am working on someone elses truck right now, and a thought came to me about plugging the lower fitting on the prop valve.....Is it necessary???

 

Since it looks like the MJ prop valve isn't bored all the way through anyway, does it matter if you put a plug in that port? Is anytone running the MJ prop valve with that port NOT plugged?

 

I will plug the one I am working on, but i was just curious if anyone removed the line from the valve and left it unplugged.

 

Thanks,

Andy

[Eagle]

I am working on someone elses truck right now, and a thought came to me about plugging the lower fitting on the prop valve.....Is it necessary???

 

Since it looks like the MJ prop valve isn't bored all the way through anyway, does it matter if you put a plug in that port? Is anytone running the MJ prop valve with that port NOT plugged?

 

I will plug the one I am working on, but i was just curious if anyone removed the line from the valve and left it unplugged.

 

Thanks,

Andy

Hey, Andy -

 

Long time no talk. How's it going? Say hi to your wife for me.

 

I would not trust that bypass to not be bored through. The one I cut open wasn't, but I cut ONLY one. It is obviously intended to be bored through, otherwise it would not (could not) function as a bypass, and that's what it's for. The annotated version of my photo (kindly produced by jtdesigns) shows how it should work. If you don't plug it, under normal conditions there should never be any pressure or fluid getting to it. But, if you lose the fronts, the slider will more, directing pressure to that bypass, and then it's an open circuit. That means you'll have NO brakes.

 

All you need to plug it is a fine thread bolt. I don't remember if it's a 5/16" or a 3/8" but it's one of those two, I'm pretty certain. (Oh, be safe and buy a 7/16" while you're at the bolt emporium.) It is definitely a fine thread (SAE), though, not coarse (UNC).

 

You could just put a dab of RTV on the end of the bolt and stick it in there. I wanted it to look a bit neater, so I cut it to length to barely kiss the seat with an O-ring on the bolt, then I also added RTV so when I installed it, it seats with the head compressing the O-ring on the valve body and the RTV sealing the actual hole in the valve. That should translate to a double seal. I'm all about redundancy when it comes to my life and things designed to protect it.

[Andy in Pa]

I am working on someone elses truck right now, and a thought came to me about plugging the lower fitting on the prop valve.....Is it necessary???

 

Since it looks like the MJ prop valve isn't bored all the way through anyway, does it matter if you put a plug in that port? Is anytone running the MJ prop valve with that port NOT plugged?

 

I will plug the one I am working on, but i was just curious if anyone removed the line from the valve and left it unplugged.

 

Thanks,

Andy

Hey, Andy -

 

Long time no talk. How's it going? Say hi to your wife for me.

 

I would not trust that bypass to not be bored through. The one I cut open wasn't, but I cut ONLY one. It is obviously intended to be bored through, otherwise it would not (could not) function as a bypass, and that's what it's for. The annotated version of my photo (kindly produced by jtdesigns) shows how it should work. If you don't plug it, under normal conditions there should never be any pressure or fluid getting to it. But, if you lose the fronts, the slider will more, directing pressure to that bypass, and then it's an open circuit. That means you'll have NO brakes.

 

All you need to plug it is a fine thread bolt. I don't remember if it's a 5/16" or a 3/8" but it's one of those two, I'm pretty certain. (Oh, be safe and buy a 7/16" while you're at the bolt emporium.) It is definitely a fine thread (SAE), though, not coarse (UNC).

 

You could just put a dab of RTV on the end of the bolt and stick it in there. I wanted it to look a bit neater, so I cut it to length to barely kiss the seat with an O-ring on the bolt, then I also added RTV so when I installed it, it seats with the head compressing the O-ring on the valve body and the RTV sealing the actual hole in the valve. That should translate to a double seal. I'm all about redundancy when it comes to my life and things designed to protect it.

 

Hi Harwood,

All is good here, the kids are getting big and Leah and I are doing well.

 

Thanks for replying to my post.... yeah, thats kind of what I figured. I was planning on getting a bolt and sealing that port up (especially since it isn't my truck), but since I was re-reading this post to refresh my memory, I was curious if anyone removed it and tried it without plugging that port.

 

One more question--

I was tracing the lines, and as far as I can tell, the line that comes from the front of the prop valve is the one that DOES NOT have the tee in it back at the axle..... Correct? The brake line is in good shape on this truck, so no need to replace it.

 

Also, I am working on an 87 MJ, and I was able to get BOTH of the brakelines loose from the load sensing valve, AND the brakeline down to the axle without breaking/having to cut anything!!!! I was amazed!!!

 

A.

[MiNi Beast]

good read, been thinking on what to do with the brakes with the 44/60 install and think I may just plug the mj valve and keep the stock booster and see how that goes and go from their if not enough.

[MiNi Beast]

found it, was looking for this thread. :wrench:

[MJeep]

If you get premature lockup of the rear wheels, either use smaller diameter rear wheel cylinders or buy a Wilwood adjustable proportioning valve from Summit Racing and put that in the single line to the rear.

 

Which valve would work, as they have several. And where would you locate it? In the cab or can it just be attatched to the frame?

[HOrnbrod]

http://www.comancheclub.com/forums/viewtopic.php?f=2&t=32143&start=15

 

I would locate it at the same place Jon (jeepcoma) did. :cheers:

[shawn]

does anyone still have the diagrams for the re-plumbing of the distribution block? they seem to have been removed from this thread. ( i think I'm looking in the right place .....).

[Alexia]

does anyone still have the diagrams for the re-plumbing of the distribution block? they seem to have been removed from this thread. ( i think I'm looking in the right place .....).

Not a diagram, but this should help. The rear port goes to the front left. The bottom rear port goes to the front right. The bottom front port goes to the rear. All of the lines there are straight from the dealership prebent for a 1997 XJ and were roughly $30 total. The short line from the XJ for bottom front port hooks right up to the feed line that goes to the MJ rear brakes. This setup eliminates the rear load sensing adjustment valve.

 

[Eagle]

Alexia's photo shows an XJ proportioning valve. Pete's photo, in the second post in this thread, shows an MJ metering block.

 

Take your pick.

 

Personally, knowing that the purpose of the XJ proportioning valve is to ensure that the rear brakes don't do anything until you hit panic stop pressure, which will then result in the rears locking up before the fronts and the back end of the truck suddenly preceding the front down the road, I think putting an XJ valve into an MJ is a VERY bad idea. But ... I'm an olde pharte, and I prefer to have brakes that work all the time, not just when some dweeb engineer who probably never drove a Jeep or a truck in his life thinks they should work.

[ARareBreed]

I'm trying to figure out what to do here. Anyone who can chime in would be greatly appreciated.

 

I want simplicity but functionality. I want to remove the load sensing valve because its confusing won't work with my Ford 8.8 axle. Therefore, is it best to just plug the MJ front valve hole and add a Wilwood 260-8419 Adjustable Proportioning Valve Knob for the rear from the beginning?

 

Also what would be a suitable upgrade for BB and MC?

[jeeptruck636]

I'm trying to figure out what to do here. Anyone who can chime in would be greatly appreciated.

 

I want simplicity but functionality. I want to remove the load sensing valve because its confusing won't work with my Ford 8.8 axle. Therefore, is it best to just plug the MJ front valve hole and add a Wilwood 260-8419 Adjustable Proportioning Valve Knob for the rear from the beginning?

I wanted to get rid of the load sensing valve, and have adjustability. So I used a Wilwood 260-11179 proportioning valve. It gives full flow to the front brakes, and has a adjustable rear output. It also has a built in pressure switch. I ended up running new NiCopp brake lines and got rid of the extra rear line. This could be a option for you.

 

 

Also what would be a suitable upgrade for BB and MC?

I am using a 96 brake booster/ master cylinder, and on my '91 everything bolted right in.

* Picture was taken before it was finished.

[Eagle]

I wanted to get rid of the load sensing valve, and have adjustability. So I used a Wilwood 260-11179 proportioning valve. It gives full flow to the front brakes, and has a adjustable rear output. It also has a built in pressure switch. I ended up running new NiCopp brake lines and got rid of the extra rear line. This could be a option for you.

...

I am using a 96 brake booster/ master cylinder, and on my '91 everything bolted right in.

Very nicely done.

 

Where did you get the Wilwood proportioning valve? I don't think that's the same one that Chrysler used to sell through the Mopar Performance catalog.

[jeeptruck636]

Very nicely done.

Where did you get the Wilwood proportioning valve? I don't think that's the same one that Chrysler used to sell through the Mopar Performance catalog.

 

 

Thanks, I got the valve from Jegs for $78. I am not sure if it was offered through the Mopar Performance catalog.