I know there are 10,000 threads on rear disc swaps so please save me the time of reading all of them. I know they are interchangeable for some years.. Does someone have an idea on which will fit my 2001 XJ with a Dana 35c? I just need the year of ZJ I can cannibalize. As soon as i get this little piece of info I'm going to the junk yard. Had a close call this morning. Brakes suck..
Thanks!!

 

I know this one is an option, but i don't have that kind of money at the moment..

http://www.4wd.com/productdetails.as...&partID=55770#

 

95-98 with the 35. 44a version will work but the 35 will be easier.

 

Thanks a bunch. Just found a 96 being parted out.

 

How about the proportioning valve for the ZJ? Will it work on my XJ? Or do i need to find a different valve?

 

The ZJ proportioning valve will work but you can save yourself a lot of hassle. Go to your proportioning valve, take off the side screw and take the little rubber o-ring out of it then bleed the system. It gives you pretty much the same results as replacing the whole prop valve with a ZJ one.

 

This will correct the pressure to the rear?

 

Really? what does the O ring do? Just restrict flow?

 

From what I understand (and correct me if I'm wrong), the o-ring restricts the flow and causes residual pressure on the rear brakes. Drum brakes need the residual pressure to operate correctly while disc brakes will only burn up with it, drum brakes also need less flow since the piston area in them is smaller than that of disc brakes. I've done multiple rear disc swaps on buddies rigs and we did this and they all work 100x better than stock (you don't really realize how much drum brakes suck till you swap on disc).

 

I don't mind spending the extra $ getting the new prop valve if it is the better option.. I am a shade tree mechanic so, i want it to be a safe and easy a conversion as possible.

 

But does it properly distribute the pressure to the rear brakes? It seems that it would correct negative pressure (when the brakes are not engaged) but what about when applying the brakes? Wouldn't it just apply the same amount of pressure to the rear as with the drum?

 

The issue isn't so much the pressure, it's the volume. Pressure is based on volume and area, the more the area, the higher the volume in order to achieve the same about of pressure. By opening that o-ring, it removes the restriction and the volume of fluid increases (sorry, had to use my education for something! ).

From years of being a mechanic and years of modifying and working on Jeeps, I have yet to see any ill effects from just doing this quick and easy alteration. Two of my wheeling buddies did this (one with an XJ and one with a TJ) while I swapped to the ZJ proportioning valve on my old XJ. I went the whole route with he prop valve, master cylinder, and had Cadillac disc brakes on the rear (came with the axle I bought) and there was no real difference between his stopping power and my stopping power (this was when I dropped down to 33's just to test this out). My buddy with the TJ only has 30's on his but it stops real fast now. This was with three different disc brake setups though (mine were Cadillac, my buddies XJ were Explorer and my buddies TJ were ZJ brakes).

I kinda went rambling there a bit but think I answered the question.

 

I bought a rear disk conversion kit for my XJ. I will see if it says anything in the instructions about it...

 

That is good to know. I just got done taking the hardware off of the ZJ and the guy sold the proportioning valve with the master cylinder to someone else, so I guess the decision has been made for me. I will try it. Thank you for the info.. And don't worry about rambling. I have precious little knowledge as it is. All the help I can get is appreciated.

 

Please let me know what you find out.