So I’ve posted before about this, brought my Jeep to a shop and basically for no answers, but I swapped in a ford d44 front axle and a sterling 10.5 rear on my 01 Cherokee, both axles are disc brakes, and the pads are dragging on all 4 corners. Plenty of brake pressure and stopping fine but the calipers aren’t releasing all the way off. The rear calipers seem ****ty and I’ll change them, but I what I’m wondering is is there something with the stock Cherokee brake system setup for disc front drum rear that is making all 4 corners drag? I don’t want to spend $1000 on brakes all the way around and have them still dragging.

 

What year is your XJ?
All I can tell you is that when we do the rear disc conversion on our OEM rears most swap out the proportioning valve guts for those out of a ZJ with rear discs. Some don't and have no issues. MAYBE your set up is more critical. If you do this don't mix the parts as it will leak.

 

The Jeep is a 2001. I was under the understanding the proportioning valve is to allow the front brakes to squeeze first and almost delay the rear so it doesn’t lock up easily in the back. Like I said my problem isn’t stopping and break pressure, it’s getting the calipers to release.

 

My guess is what your wondering about. The stock Cherokee set up may be the cause.
See if any of this will help (especially the last post):
https://www.pirate4x4.com/forum/jeep...-ton-swap.html
Trouble shoot 101: with the brakes locked remove the rod from the pedal, if this relieves the problem, the rod is too long.
If you still have the problem, loosen the nuts that hold the master cylinder to the booster, remove the master cylinder if you have to, if the problem still exists get rid of the proportioning/metering valve. If the removal of the master cylinder cured the problem, the rod that is part of the booster is too long, this is where you have probably read about using "washers" to shim the master cylinder away from the booster. Most booster have an adjustable rod.
TroubToot 101: with the brakes locked remove the rod from the pedal, if this relieves the problem, the rod is too long.
If you still have the problem, loosen the nuts that hold the master cylinder to the booster, remove the master cylinder if you have to, if the problem still exists get rid of the proportioning/metering valve. If the removal of the master cylinder cured the problem, the rod that is part of the booster is too long, this is where you have probably read about using "washers" to shim the master cylinder away from the booster. Most booster have an adjustable rod.le shoot 101: with the brakes locked remove the rod from the pedal, if this relieves the problem, the rod is too long.
If you still have the problem, loosen the nuts that hold the master cylinder to the booster, remove the master cylinder if you have to, if the problem still exists get rid of the proportioning/metering valve. If the removal of the master cylinder cured the problem, the rod that is part of the booster is too long, this is where you have probably read about using "washers" to shim the master cylinder away from the booster. Most booster have an adjustable rod.
Trouble shoot 101: with the brakes locked remove the rod from the pedal, if this relieves the problem, the rod is too long.
If you still have the problem, loosen the nuts that hold the master cylinder to the booster, remove the master cylinder if you have to, if the problem still exists get rid of the proportioning/metering valve. If the removal of the master cylinder cured the problem, the rod that is part of the booster is too long, this is where you have probably read about using "washers" to shim the master cylinder away from the booster. Most booster have an adjustable rod.

 

Also for this, you’re saying you can just take the spring and plunger out of a ZJ and it goes right in the xj proportioning valve or you need to change out the entire block?

 

Just the spring,plunger,and threaded cap. Like said before don't mix the XJ and ZJ parts. There's a lot of tension when compressing the parts to get the cap started.

 

So slide the spring plunger and cap out of a ZJ and put it in the proportioning valve of my XJ?

 

Yep. Out of a ZJ with rear discs.

 

Thanks man!

 

Good luck with her.