Disc Brake Conversion

[Island XJ]

island xj didn't mean to knock on anyone just wondering. but ok so people are saying that i can just swap out my 35 and put in a ZJ 8.25 right?? So the question is then what ZJ year would i want, do the gears i have in my 35 fit in the 8.25, does the mounts for the shocks fit and is the axle the same length which would make the mounting points for the leafs the same. please help bc i might just put this 8.25 in my jeep and then i would get the brakes and the good axle. So if this is good what is the axle name for instance i have a Dana 35 what is the Zj a Dana 8.25?

I didn't mean to sound critical, i'm just a redneck.
You can't swap in a ZJ 8.25 without some modifications to the axle. ZJ's are coil sprung in the rear end and yours is leaf sprung. You can bolt up an XJ 8.25 though if you can find one. They are pretty plentiful up here in Canada, but I have heard they are harder to find in the US. The 8.25 is a DaimlerChrysler rear end, and people often refer to it as the Chrysler 8.25. To match the gears to your jeep, you have to find one that came out of a similar vehicle. The automatics and the standards came with different gears. So if yours is an auto, you need to find an 8.25 that came with an auto. ( i can't remember what the ratios are but you can find them by searching this site for "stock gears", someone willknow offhand, I THINK its 3.07 with a standard and 3.55 with an automatic, and some 4bangers came with 3.73s, but i could be wrong - someone correct me! ). If you are planning on moving up to larger tires in the future, I would actually recommend finding a junkyard Ford Explorer 8.8" axle instead. It will also have to be adjusted to fit your jeep (new spring and shock mounts). The newer ones came with disc brakes and have a 4.10 ratio, which will work with larger tires on the XJ. the only downside is that you then have to regear your front axle to match the 4.10. You can also look for a cherokee or ZJ D44 rear end and make that work too, but some of them came with aluminum differentials that i think suck. There is quite a bit of research to do here in order to do this right. Its not terrribly involved to change out your axle, but you need to have the time, flexibiltiy and $ to do it right. I suggest starting to search and email people who have done it and ask what there recommendations are before taking it on. There are a million things you can do to an XJ to make it more functional, larger tires, stronger axles and lower gears are great ideas. I have a narrowed ford 9" with custom axleshafts on one of my XJs, if i had to do them all over again, I would find one that fits adn save the custom $.
just another 2 cents...

 

[RichP]

As long as yours is running ok for a DD then start hitting some boneyards, find an 8.25 or D44, take it home and do the mods in your house. They are easy to work on out the vehicle and just as easy to take to a shop to do stuff you can't do. What you could do is get it, pull the axles and fit a set of ZJ discs, with it out you have all the time in the world and it would make a good winter project. Look for a front and do that one too, gear them up the same and then do the swap on both ends.

 

[bigwhitey]

As long as yours is running ok for a DD then start hitting some boneyards, find an 8.25 or D44, take it home and do the mods in your house. They are easy to work on out the vehicle and just as easy to take to a shop to do stuff you can't do. What you could do is get it, pull the axles and fit a set of ZJ discs, with it out you have all the time in the world and it would make a good winter project. Look for a front and do that one too, gear them up the same and then do the swap on both ends.

Thats what I did. I had a 94 8.25 (27 spline) and went to the junkyards looking for a d-44. When I finaly found it I paid 200 bucks and learned how to install one by removing it from the old XJ it was under (no practicing on my own). Then I pulled the ZJ disc brakeshard lines, pads, rotors, backing plates, everthing. brought them home and made them fit. then last weekend I had 4wheel parts install the gears I wanted brought it home and installed it under my XJ. Now I just have to have the front regeared to match the back next week.
It was much easier learning at the junk yard and on my back porch then on my daily driver and saved me 60 bucks an hour in labor.

 

[Jeep839]

well thank you everyone for the info and all the great ideas i think that i have all my options and i agree with you guys that just try and find something now and slowwly put it all together. I have no money bc i am going to college right now so slowly gathering the parts would work great. I really appreciate the input.

 

[Boris T]

well thank you everyone for the info and all the great ideas i think that i have all my options and i agree with you guys that just try and find something now and slowwly put it all together. I have no money bc i am going to college right now so slowly gathering the parts would work great. I really appreciate the input.

Glad to help and I am with you... Going to school takes all the cash
:lecture:

Travis

 

[roke40]

Or you can use all jeep parts from a ZJ on to a 35, if you have an 8.25 same thing, OR you could find a newer liberty and swap it's factocy equipped 8.25 disc brake rear in. No welding required and you don't have to remember 'is that an 81 or 83 caddy disc and ford pads' or was it 'caddy pads and ford discs'...

There would be welding required on the Liberty axle. They have coils in the rear so the coil pads would have to be cut off and leaf spring perches welded on.

 

[roke40]

I didn't mean to sound critical, i'm just a redneck.
You can't swap in a ZJ 8.25 without some modifications to the axle.

I don't want to sound too critical either but you can't swap in a ZJ 8.25 at all because they don't exist. ZJs either came with 35 or an aluminum center 44. Neither is worth swapping.

 

[PWRDrill]

Thats what I did. I had a 94 8.25 (27 spline) and went to the junkyards looking for a d-44. When I finaly found it I paid 200 bucks and learned how to install one by removing it from the old XJ it was under (no practicing on my own). Then I pulled the ZJ disc brakeshard lines, pads, rotors, backing plates, everthing. brought them home and made them fit. then last weekend I had 4wheel parts install the gears I wanted brought it home and installed it under my XJ. Now I just have to have the front regeared to match the back next week.
It was much easier learning at the junk yard and on my back porch then on my daily driver and saved me 60 bucks an hour in labor.

From what I'm reading you put ZJ discs from the aluminum D44 on an XJ D44 correct? I'm very interested in doing this as well.

How difficult was the modification?

Kevin

 

[bigwhitey]

From what I'm reading you put ZJ discs from the aluminum D44 on an XJ D44 correct? I'm very interested in doing this as well.

How difficult was the modification?

Kevin

you just have to take it off the ZJ, take off yours, line up and drill the holes, change the reatainer plates and bolt it back up.

 

[BCKNBLK]

Definitely go with the hardware from the ZJ ('94-'98 Grand). I just looked into the same conversion for my '01 XJ (60th Anniv. Ed, All black and all sexy btw) and came across a guy who not only did the conversion, but took photo's and wrote down the procedure and put the whole shebang online for anyone to copy for free! Free is good. The job sounds and looks like a piece of cake and shouldnt take more than a day. Cant set up a link for you, but the site is:
Mywebpages.comcast.net. Follow the yellow brick road to the disc brake swap and print it out. It doesnt get any easier! If I knew the guy, Id give him a sixer of MGD for setting the whole thing up online for all of us!

 

[ASJackman]

Definitely go with the hardware from the ZJ ('94-'98 Grand). I just looked into the same conversion for my '01 XJ (60th Anniv. Ed, All black and all sexy btw) and came across a guy who not only did the conversion, but took photo's and wrote down the procedure and put the whole shebang online for anyone to copy for free! Free is good. The job sounds and looks like a piece of cake and shouldnt take more than a day. Cant set up a link for you, but the site is:
Mywebpages.comcast.net. Follow the yellow brick road to the disc brake swap and print it out. It doesnt get any easier! If I knew the guy, Id give him a sixer of MGD for setting the whole thing up online for all of us!

Try copying the website, the one you gave is a generic website, nothing to follow.

 

[Jackhill442]

I have the TSM rear disc kit and I love it. It took some rigging to get it to work, and the adjustable proportioning valve was a pain, but the brakes are so much better. Love the looks of the rear discs, too!

 

[XJ_ranger]

im a fun of drum breaks, just because then you dont have rotor cooling holes getting pluged with mud and breaks overheating... but thats just me

 

[Dirk Pitt]

try this one...

http://geocities.com/dcpaschal/mitch.html

hth

 

[Billm]

try this one...

http://geocities.com/dcpaschal/mitch.html

hth

That link doesn't work. I even tried "www" in front of it.

Bill

 

[XJack]

Do a search on here for rear disc conversion - lots of good tech info.

Here's a start:

http://madxj.com/MADXJ/technical/technicalfiles/BAzjRearDiscsOnXJ/ZJrearDiscsOnXJ.htm

http://www.stu-offroad.com/suspension/d44brake/bc-1.htm

http://jeepin.com/features/cvdiscs/index.asp

http://members.tripod.com/cherokeekid5/zj_axle_build_up.htm

edit: Ugh... Thread zombie..

 

[MGrobe]

http://home.comcast.net/~derek.paschal/mitch.html

A parts list that someone compiled:

Backing Plate (Left) - Part# 4762129
Backing Plate (Right) - Part# 4762128
Brake Rotor (2) - Part# 52008184
Parking Brake Lever Boot (2) Part# 4762124
Banjo Bolt (2) - Part# J4006700
Brake Caliper (Left) - Part# 4762103
Brake Caliper (Right) - Part# 4762102
Caliper Bushing (4) - Part# 4762106
Caliper Sleeve (4) - Part# 4762105
Brake Caliper Bolts (4) - Part# 5253000
Brake Hose Washer (4) - Part# J3237672
Caliper Mounting Bracket (Left) - Part# 4796343
Caliper Mounting Bracket (Right) - Part# 4796342
Flex Line (Left) - Part# 52008663
Flex Line (Right) - Part# 52008662
Proportioning Valve - Part# 52009061AB
Parking Brake Lever (2) (Slide) - Part# 4762132
Parking Brake Lever (Left) - Part# 4762130
Parking Brake Lever (Right) - Part# 4762131
Parking Brake Adjusting Nut (2) - Part# 4762118
Parking Brake Adjusting Screw (2) - Part# 4762120
Parking Brake Adjusting Socket (2) - Part# 4762115
Parking Brake Hold Down Clip (4) - Part# 4762125
Parking Brake Hold Down Pin (4) - Part# 4762126
Parking Brake Spring 2 (Lower) - Part# 4762116
Parking Brake Spring 2 (Upper) - Part# 4762127
Rear Disc Brake Pads - Part# 4883717AA
Parking Brake Shoes - Part# 4796337