Rear Disc Brake Conversion
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Newbie
Joined: Aug 2011
Posts: 18
Likes: 0
From: Robinson IL
Year: 2001
Model: Cherokee
Engine: 4.o
I have an 01 XJ Sport I'm wondering if anyone has installed a rear disc brake conversion and if so, is it an easy job to do yourself and what brand because I've seen huge price differences in the ones I've found online. My XJ is my work truck and I drive over 1000 miles per week so I'd much rather have all disc brakes. Any help or advice is much appreciated.
Senior Member
Joined: Jul 2011
Posts: 598
Likes: 1
From: Wilmington, NC
Year: 1997
Model: Cherokee
Engine: 4.0L
Most of the kits you are probably looking at are based on the ZJ rear disc brakes which can usually be done for much cheaper than what those kits cost if you shop around online and have decent junk yards near you.
The conversion itself is pretty straight forward. You have to do some grinding if you have an 8.25 axle (but it isn't any sort of precision work) and you have to come up with something for the parking brake cable should you decide to retain the parking brake.
All of the parts needed are off-the-shelf ZJ. The 2 parts that can be tough to find are the backing plates/caliper brackets and the parking brake actuators. Those are junkyard or dealer most likely.
You do have to pull the axles to do the swap however. Simple but an added step beyond typical brake work.
The conversion itself is pretty straight forward. You have to do some grinding if you have an 8.25 axle (but it isn't any sort of precision work) and you have to come up with something for the parking brake cable should you decide to retain the parking brake.
All of the parts needed are off-the-shelf ZJ. The 2 parts that can be tough to find are the backing plates/caliper brackets and the parking brake actuators. Those are junkyard or dealer most likely.
You do have to pull the axles to do the swap however. Simple but an added step beyond typical brake work.
CF Veteran

Joined: Sep 2009
Posts: 3,612
Likes: 0
From: West Valley
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Heres an awesome writup regarding the ZJ conversion.
https://www.cherokeeforum.com/f51/re...-8-25-a-57807/
https://www.cherokeeforum.com/f51/re...-8-25-a-57807/
ALso to help with the braking situation you can either change the prop valve spring
ZJ one is shorter and used with 4wd brakes.

Or you can use a 78 grand marquis w/4wheel disc brakes MC (1 1/8 bore) and that should give you more then enough brakes to stop you rig. there is a lil fab work involved in this.. and you will have to be able to do double flares on tubing.
ZJ one is shorter and used with 4wd brakes.
Or you can use a 78 grand marquis w/4wheel disc brakes MC (1 1/8 bore) and that should give you more then enough brakes to stop you rig. there is a lil fab work involved in this.. and you will have to be able to do double flares on tubing.
The TJ retainer has a ring built onto so it eliminates the need for having a ring cut to keep the right pressure on the oil seal.....
This was done on my XJ d44 I had under my chop top until summer 2010. Brakes worked great with the zj prop valve upgrade.
I did the m/c upgrade when I went to chevy 3/4 ton brakes.
This was done on my XJ d44 I had under my chop top until summer 2010. Brakes worked great with the zj prop valve upgrade.
I did the m/c upgrade when I went to chevy 3/4 ton brakes.
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Renix Super Guru
Joined: Mar 2008
Posts: 24,653
Likes: 19
From: In yourz postez fissin jurr spelinzs
Year: 1990XJ/1989MJ
Model: Comanche
Engine: 4.0L Renix
Has anyone considered the Liberty disc brakes. The Lib also has a 8.25 rearend. Not sure if everything will transfer but it is worth a look to see if it is feasible.
Newbie
Joined: Sep 2011
Posts: 4
Likes: 0
From: Louisville KY
Year: 2001
Model: Cherokee
Engine: 4.0L Straight-Six
For a Junkyard swap you need the backing plates, rotors, and calipers from a ZJ with a 35 and discs. If you have ABS and want to keep it, you need the ZJ axle shafts (or replace your tone rings) and the ZJ ABS wheel speed sensors as well. You can also replace your proportioning valve with the ZJ one as well.
ITs all bolt off/bolt on except for the e-brake cables. There are a couple of options for that, you can get the ZJ cables, modify your cables, or modify the e-brake lever on the brakes themselves (which is what I did).

Alternatively you can fork out some cash for an off the shelf kit you can find online, which is usually just new ZJ or - I think - explorer brakes.
ITs all bolt off/bolt on except for the e-brake cables. There are a couple of options for that, you can get the ZJ cables, modify your cables, or modify the e-brake lever on the brakes themselves (which is what I did).

Alternatively you can fork out some cash for an off the shelf kit you can find online, which is usually just new ZJ or - I think - explorer brakes.
Last edited by Kettles; Sep 11, 2011 at 11:15 AM.
Senior Member
Joined: Oct 2010
Posts: 842
Likes: 4
From: Everett, WA
Year: 1996
Model: Grand Cherokee
Engine: 5.2L
IMO this is a MUST when going to rear discs. When I swapped in my 8.8, I had no brakes due to the stock MC not moving enough fluid. Swapped in a marquis MC and that took care of it.
Member
Joined: Mar 2011
Posts: 138
Likes: 0
From: Knoxville, TN
Year: 1993
Model: Cherokee
Engine: 4.0
I'm guessing since Libertys are not a common site in junkyards yet, no one's tried it. I have a feeling it'll work about the same as any other setup
Senior Member
Joined: Oct 2010
Posts: 842
Likes: 4
From: Everett, WA
Year: 1996
Model: Grand Cherokee
Engine: 5.2L


