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  #1  
Old December 19th, 2008, 12:23
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Nuke Proof Nuke Proof is offline
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Looking for a ZJ prop valve

I've been looking for a couple of weeks now and cannot find one anywhere. Does anyone know of a parts dealer or wrecking yard that might have a line on one? Or does anyone know of another way to have a rear disc brakes on an 89 XJ without dragging the rear calipers? Any help would be appreciated.

Thanks

Last edited by Nuke Proof; December 19th, 2008 at 12:27.
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Old December 19th, 2008, 13:08
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cal cal is offline
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Re: Looking for a ZJ prop valve

As far as I have been able to tell, the ZJ prop valve is no major upgrade if any at all.

If your rear brakes are dragging, I'd look for a problem the same way you would if your drums had been dragging - bad caliper, pinched brake line, etc.
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  #3  
Old December 19th, 2008, 13:49
Jess Jess is offline
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Re: Looking for a ZJ prop valve

I got my full WJ setup (booster, mc, prop valve) on ebay. The whole setup with shipping was less than $30.
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  #4  
Old December 19th, 2008, 16:35
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Re: Looking for a ZJ prop valve

Thanks guys. I'll check ebay.
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  #5  
Old December 19th, 2008, 17:18
shmoken875 shmoken875 is offline
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Re: Looking for a ZJ prop valve

Quote:
Originally Posted by Nuke Proof View Post
Thanks guys. I'll check ebay.
I run rear disks on a 9", all I did was remove the o-ring out of my distribution block and ran an aftermarket proportioning valve on the rear line.
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Old December 19th, 2008, 17:20
shmoken875 shmoken875 is offline
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Re: Looking for a ZJ prop valve

Didn't see you said 89, might as well follow jess's advise to get a dual diaphragm booster.
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Old December 19th, 2008, 17:39
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JeepFreak21 JeepFreak21 is offline
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Re: Looking for a ZJ prop valve

There's a couple ZJs in my local PnP
Billy
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  #8  
Old December 19th, 2008, 18:31
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Nuke Proof Nuke Proof is offline
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Re: Looking for a ZJ prop valve

I spoke with Cal pretty extensively and it looks like my best option is to do what Jess suggested. My only problem I have now is finding a WJ MC and booster for a reasonable price. I found one at a couple of JY's, but one was $150 and the other was $115 for the MC and booster.

I'll keep checking, but I called about a dozen today and only those two had one in stock.

Thanks again guys
Darin
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  #9  
Old December 22nd, 2008, 22:17
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Nuke Proof Nuke Proof is offline
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Re: Looking for a ZJ prop valve

Where is a good place to locate a WJ MC and booster? If anyone has a line, please let me know.
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  #10  
Old December 23rd, 2008, 07:07
badron badron is offline
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Re: Looking for a ZJ prop valve

AS for the P-value goes. Any disk/disk P-value will work. Some are easier to bolt up that about it. The guts for a ZJ P-value MAY slide right in. This has work for some. Making the install super easy.
Removing the O ring works for many but you lose your independent systems that way. If it maters. The rear may lockup a bit sooner to. But big tires will hide this for the most part. I asume you running big tires anyway hence the need for more braking.
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Old December 23rd, 2008, 07:11
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Re: Looking for a ZJ prop valve

How many people actually have found swapping p-valves helps them?

I have a ZJ booster/MC and didn't need to touch my stock XJ p-valve. I have no problems with the rear brakes dragging at all last time I checked.
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Old December 23rd, 2008, 08:28
badron badron is offline
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Re: Looking for a ZJ prop valve

I have a ZJ booster/MC and didn't need to touch my stock XJ p-valve.
============================================
Changing of the P-value is for the disk/disk conversion. The P-value cares little about what booster (if any) or MC is in use.

============================================
How many people actually have found swapping p-valves helps them?
===============================================
Few will ever FELL any change. But using a disk/drum P-value on a disk/disk system may permit the rear disk to engage before the fronts. With stock or near stock tires the wrong P-value may show up as early rear lockup. Even more promoted then the stock setup.
But most XJ that do the disk/disk conversion do so because of much larger tires. The larger tires tend to prevent lockup. The most they will see is MAYBE rear pads wearing faster then the front.
Also many XJ run with tons of heavy junk in the trunk. Spare axles big tool boxes beer etc etc. In there case the "wrong" P-value may proved a better front to back braking bias for there load.
Truly even braking is a balancing act. That few ever see or care about as long as they stop before they hit the tree,
All this is (IMO)
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Old December 23rd, 2008, 12:19
89xj 89xj is offline
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Re: Looking for a ZJ prop valve

Quote:
Originally Posted by Nuke Proof View Post
Where is a good place to locate a WJ MC and booster? If anyone has a line, please let me know.
if your still looking for the wj set-up, i went to car-parts.com and found a local junk yard that had it. went down to junkyard to pay for it(65$ for the booster and master) as they wont pull it off until you pay. 30 minutes later i was out of there with the parts i needed. bought a double flaring kit and some brake lines and installed it. night and day difference on my 89(still have the 10" drums on the rear).
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Old December 23rd, 2008, 15:41
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Re: Looking for a ZJ prop valve

Quote:
Originally Posted by 89xj View Post
if your still looking for the wj set-up, i went to car-parts.com and found a local junk yard that had it. went down to junkyard to pay for it(65$ for the booster and master) as they wont pull it off until you pay. 30 minutes later i was out of there with the parts i needed. bought a double flaring kit and some brake lines and installed it. night and day difference on my 89(still have the 10" drums on the rear).
Thanks, I keep forgeting about car-parts.com.

As far as the prop valve is concerned. After speaking with Cal pretty extensively, I am going to leave the XJ one in.

Thanks again

Does it matter what options the WJ has? Or will any master out of a 99 and newer Grand Cher work?

Last edited by Nuke Proof; December 23rd, 2008 at 15:46.
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  #15  
Old December 23rd, 2008, 19:08
Oatmeal Oatmeal is offline
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Re: Looking for a ZJ prop valve

When I first did my rear disc swap I ran the original prop valve for a while (this is on a '96 btw so, I already had the better booster) and it stopped ok (not great). I went to a Jeep only wrecking yard and picked up a ZJ valve for about $30 and just swapped the guts (much easier than swapping valves as the ZJ valve has a different mounting bracket) and it did indeed stop much better........discs require more pressure than drums (which are self energizing) so, using a prop valve that's metered for drums won't give full pressure to your new rear discs and most of the stopping will be done by the fronts............I would do the swap-----------Hans

Last edited by Oatmeal; December 23rd, 2008 at 19:14.
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