D35 -> 8.25 w/ disc swap. A few questions...

Basic background: I've got an '89 XJ Limited (D30 Fr / D35 Rear / NP242) that I am going to swap a 29-spline 8.25 into. I have already done away with the ABS, and replaced the entire braking system(including the hard lines on the chassis) with the non-ABS system from a '96 that I parted out. So, I have the bigger brake booster and the associated master cylinder already. I still have the D35 with the original ABS drum setup.

I am going to the junkyards this weekend to collect a) the 8.25 rear axle, and b) rear disc brake swap parts. I've read through everything available on the site, and I still have a few questions that I'm hoping to have answered prior to making my trip to the yards. My plan is to get the 8.25, do the disc swap to it, and swap it into my truck already assembled and ready to go. So here are my questions:

Axle swap stuff:
*I'm going for a '97-> 29-spline 8.25. I know i need to get it from a truck with a full size spare. Any other things to look out for? Any years to avoid? I seem to remember something about the 00-01 trucks having a less desirable 8.25. Also, do I need the rear driveshaft, or any other parts(brackets, plates, whatever) to do the swap in place of my D35? I will be buying new u-bolts, so that's covered. I just want to be sure I get anything else I need while I'm at the yard.

Rear disc stuff:
*E-brake cables - are the Explorer, ZJ, or KJ cables a direct swap with the correct ends? I don't want to do the looped-over cables with a clamp on them as I've seen done in a number of swaps here.
*ZJ Backing plates vs KJ Backing plates - I have access to brand new KJ backing plates that include the e-brake setup at very reasonable prices(thanks to a friend in the local Chrysler dealer's parts department). My thought was to use these as I won't have to grind out the center of the backing plates as I would with the ZJ ones, and I can avoid buying and assembling all new e-brake parts. If I do go this route - what will I need from a ZJ? I intend to use new rotors, pads, and hoses, which(and correct me if I'm wrong) leaves me needing just calipers and some mounting hardware from the ZJ.
*Braided stainless steel brake hoses - any suggestions on vendors? I plan to upgrade the fronts using WJ outers later on, so if I can get a set of brake hoses that will be compatible all around, all the better.
*ZJ Proportioning valve - Any consensus on this and whether or not it's needed? And just so I'm sure I'm looking at the right thig - this is the small block that hangs out below the booster near the firewall, correct?

Thanks in advance, everyone! :viking:

some 96 8.25s were 29 spline (hit or miss) and all 97-01 8.25s were 29 spline. it doesnt matter if the jeep had a full size spare or not.

your D35 driveshaft is a little longer than that of an 8.25. if you have a lift on your xj, use your existing driveshaft to help have more spline engagement.

i modified a set of KJ e brake cables to use on my xj with an 01 8.25 with zj disks. if you use zj backing plate then use zj brake parts. if you go with kj backing plates then use kj calipers. its not a good idea to mix and match parts unless you are certain they are 100% compatible. i went with the stock soft line brake hoses from the axle hard line to the caliper. a zj prop valve helps out a ton

stewie said:

your D35 driveshaft is a little longer than that of an 8.25. if you have a lift on your xj, use your existing driveshaft to help have more spline engagement.

Click to expand...

Currently I've got a 2" BB on the truck, but I intend to go to an OME 3" setup in the near future. Should I pick up the 8.25 driveshaft to use for now and save the D35 shaft for later, or can I just stick with the D35 driveshaft?

stick with your D35 driveshaft. if you went with an 8.25 driveshaft, you would need to get the d/s out of a pre 96 xj with 8.25 because the tc output yoke changed on the late models (donnor for the 8.25).

stewie is 100% correct. Your confusion about the 00-01 axles is that the FRONT axle (the dana 30) is a low pinion on those years instead of a high pinion. The rear axle options are the same from 97-01.

Thanks for the info, guys. I managed to get myself a 29-spline 8.25" rear and all of the disc brake parts(plus some other goodies) last weekend. I have been collecting up all of the new parts that I want to replace before I install the axle(bearings, seals, etc), and I have come up with a few more questions.

Rear brake line(chassis->axle). I have a YJ hose on my truck already to work with the 2" BB. However, when I looked under my truck to just do a quick visual, I noticed that the axle vent tube in the D35 does not run through the block at the end of the brake line like it does on the 8.25. It's held on with a bolt that looks to be smaller than the 8.25 vent tube. Do I need a different hose for the 8.25?

stewie said:

stick with your D35 driveshaft. if you went with an 8.25 driveshaft, you would need to get the d/s out of a pre 96 xj with 8.25 because the tc output yoke changed on the late models (donnor for the 8.25).

Click to expand...

Is there a possibility that the D35 driveshaft will be too long if the lift is not tall enough? I ask because, in spite of the 2" BB, I'm not sure there is a whole lot of lift really going on back there, thanks to saggy stock leafs.

Also, should I pull the yoke from the D35 and move it over to the 8.25 to match the driveshaft?

I could still use a little clarification on e-brake cables, as well. I have read that Explorer cables work, or ZJ cables, or one ZJ cable and one KJ cable, or two KJ cables, etc. So I'm a little confused as to the best option on brake cables. A little guidance here would be appreciated. :wave1:

be careful and make sure u check the axle cause i have an 01 and its got the dana 35 im about to swap in an 8.8 soon

maalox said:

Is there a possibility that the D35 driveshaft will be too long if the lift is not tall enough? I ask because, in spite of the 2" BB, I'm not sure there is a whole lot of lift really going on back there, thanks to saggy stock leafs.

Click to expand...

Yes! Mine didnt work when I did this swap with 4.5" lift.

Ben

maalox said:

Thanks for the info, guys. I managed to get myself a 29-spline 8.25" rear and all of the disc brake parts(plus some other goodies) last weekend. I have been collecting up all of the new parts that I want to replace before I install the axle(bearings, seals, etc), and I have come up with a few more questions.

Rear brake line(chassis->axle). I have a YJ hose on my truck already to work with the 2" BB. However, when I looked under my truck to just do a quick visual, I noticed that the axle vent tube in the D35 does not run through the block at the end of the brake line like it does on the 8.25. It's held on with a bolt that looks to be smaller than the 8.25 vent tube. Do I need a different hose for the 8.25?



Is there a possibility that the D35 driveshaft will be too long if the lift is not tall enough? I ask because, in spite of the 2" BB, I'm not sure there is a whole lot of lift really going on back there, thanks to saggy stock leafs.

Also, should I pull the yoke from the D35 and move it over to the 8.25 to match the driveshaft?

I could still use a little clarification on e-brake cables, as well. I have read that Explorer cables work, or ZJ cables, or one ZJ cable and one KJ cable, or two KJ cables, etc. So I'm a little confused as to the best option on brake cables. A little guidance here would be appreciated. :wave1:

Click to expand...

Brake hose should work either way, iirc. I've never been asked what rear axle I had when I was replacing a brake line, and they've always fit, so I think it's the same part - I can check the parts catalog shortly.

Driveshaft - yeah, depends on lift/springs/shackles/blocks. Get the driveshaft from the donor to be on the safe side - make sure it has the same engine, transmission, and is 4WD. You don't need to move the yoke, the yokes probably aren't even compatible (not sure) and they fit the same U-joint.

E-brake cables - :dunno: sorry, hopefully someone else can clear this up