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rear proportioning valve


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Ok, I have a question. What about leaving everything alone (going with the "if it ain't broke don't fix it" theory) and swapping out axles to full width and rear disc's? The rear proportioning valve was designed for drum brakes right? I know some of you guys on here have switched to rear disc, so what did you do? Just leave it alone or take it out? I'll also be running a Ford 1 ton master cylinder, at least that's what I was told to run. Just let me know what you guys think. Thanks, Shawn. 8)

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the xj only has one prop valve. go with a newer one 97+ and they work great. i had a write up on this somewhere. :hmm:

 

Alex

Why the need for the newer one?

 

ok i still can't find my write up i had but here is a page that will help on this topic.

http://www.comancheclub.com/forums/view ... ve&start=0

 

i can't remember y the newer ones were better. if i find the write up i have i will post the link and i think it said in there y. i do know it had something to do with the xj only haveing one and something to do with discs i think.

 

another good option is an adjustable one like is mentioned in that link.

 

ok well here is part of it. still no reason to go newer except maybe for it being in better shape and the chance that it wasnt defective as some of us have found out. but the XJ only has one line going to the rear brakes. the thing to do here is to use an XJ valve and run one rear line back.

 

not sure if this was stated before on this post but the second line for the MJ rear is a safety line incase you lose your front brakes all pressure is applied to the rear, IIRC. it is not wise to run lines back without the valve because then there is a better chance of locking up your wheels, which as we all know is not good on ice and snow or even on wet pavement.

 

so what you should really do is use the XJs setup or use an adjustable valve which i think would be the better thing to do here. expecially if you are going to do the disc swap now or later on even.

 

here is a good one i was pointed to when i was asking about this.

http://www.naxja.org/forum/showthread.php?t=60086

 

as you can see once eagle jumps on this one it will be all over.

 

Alex

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Mine is removed, and I'm still using the stock MJ prop valve.

WHen my rear brakes failed I still had front brakes, the pedal travel was just messed up.

It doesn't lock the rear end often, but in wet conditions it can be a problem, and only under real heavy braking. it'[s just like any other pickup I've ever driven for that matter.

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my rear prop valve arm thing is long gone somewhere in West GA :brows:

and i only lock them up when expected. IE when people do dumb stuff around me!#*$@ truck stops just like mum&bros XJs do

while hauling 2 D44's and 2 spare 235 tires with rims and other goodies truck stopped fine.

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i've heard about people ditching it for an XJ rear prop. valve, maybe you could look into that?

 

the xj only has one prop valve. go with a newer one 97+ and they work great. i had a write up on this somewhere. :hmm:

 

Alex

The MJ only has one proportioning valve, too ... the one in the rear. What is the proportioning valve in the XJ is nothing but the brake system warning light switch in the MJ. There is no proportioning going on in that front juntion block.

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i've heard about people ditching it for an XJ rear prop. valve, maybe you could look into that?

 

the xj only has one prop valve. go with a newer one 97+ and they work great. i had a write up on this somewhere. :hmm:

 

Alex

The MJ only has one proportioning valve, too ... the one in the rear. What is the proportioning valve in the XJ is nothing but the brake system warning light switch in the MJ. There is no proportioning going on in that front juntion block.

 

i knew that but for some reason wasnting thinking when i wrote that and it came out wrong. :dunce:

 

Alex

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ok now we are talking. if you are going to do a disc swap then you need to swap to an adjustable prop valve or do away with it. an adjustable one would be the better choice here. the factory one was made for drums and will not work correctly with discs. now I'm not sayin it won't work somehow with some mods or something but it just wasnt made for discs and an adjustable one would be the way to go.

 

Alex

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yes i would assume that that would work. i have not heard of anyone doing this yet and it would need to be looked into more. the problem with the factory MJ one was that it either applys too much or not enough pressure to the discs since it was made for drums. that would be something to look into for sure. i might get on that and see what i can turn up since it might be an option for me not too far doen the road. good idea.

 

Alex

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