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brake portioning valve

afd516

afd516

NAXJA Forum User
Location
Fort Worth, Tx
I have been told by a few people that removing my portioning valve will help my rear brakes get more fluid, thus more stopping power. Is this true?

I have a 89 with a lp d44 front, (the brakes work great on front) and a 9" rear with drums (the rear works maginaly). It is a completely new system except for the master, booster, valve and lines.

For now the rear drums are as good as they are going to get until I try something I have not yet. I was going to pull the valve and see what happens. Good or bad idea?

This rig is 90% trail and 10% road.
 
Search for similar thread "proportioning valve" or "adjustable proportioning valve". We just had a lengthy topic on this and you may find the answer to your problem there.

Im a newb so dont take my word for it but as it was told to myself and others you do NOT want more pressure to the rear brakes. It will cause lock up and rear end to swing around and become the front end! :shocked:

edited: heres the thread... http://www.naxja.org/forum/showthread.php?t=81438&highlight=proportioning+valve
 
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I did a search and came up with nothing. Thanks for the link. I was going to pull the valve but have not yet because I do not know enough about it. That is why I am asking. I am not sure that it is what I need to do. I will have to research it more.
 
I just finished reading the thread that was linked. Thanks! I still have questions though. I will ask here since I am askin about altering the valve or removing it. What does removing the o-ring do.

BTW, i have 36" tires with probably 350 lbs of weight in the rear including bumper, cage, spare tire and parts, etc. I know that this is probably a factor.

I do see discs in the future for the rear but for now I want to try tweaking what I have and see the results.
 
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A related question here. Does pulling the o-ring have the same effect on the MJ proportioning valve? The MJs have an extra return line from the rear and the prop valve is different

I just swapped on Crown Vic discs and the braking in the rear is still pretty weak. I probably just need to bleed everything again, but I'm considering the o-ring mod if that doesn't do the trick.
 
The valve has whats called a residual valve that changes the pressure for the rear drum brakes. With out that valve the rear brakes will ingage first and they will most likely lock up, if you swap to disks in the rear you need to get the valve from the same car the brakes came off of. There is a difference, some people have modified there current valve but I would not recomend it. I would swap to grand cherokee rear disks, this way you do this brake work once and you don't hurt your self or your jeep in the process.
 
black93xj said:
The valve has whats called a residual valve that changes the pressure for the rear drum brakes. With out that valve the rear brakes will ingage first and they will most likely lock up, if you swap to disks in the rear you need to get the valve from the same car the brakes came off of. There is a difference, some people have modified there current valve but I would not recomend it. I would swap to grand cherokee rear disks, this way you do this brake work once and you don't hurt your self or your jeep in the process.
Click to expand...

For non-clip D35 axles, the Crown Vic brakes are an easier swap than ZJ brakes. Just have to make one spacer for under the retainer plate and then redo the hard lines to use the stock Crown Vic brakes. Everything else bolts right on. I'll finish the writeup someday...

I can't use the prop valve off most other vehicles since the MJ has the return line from the rear. Hence my question about removing the o-ring to allow more fluid flow to the rear.
 
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