ZJ discs on Chryco 8.25" in XJ

#1
So this is a pretty common mod for XJers and on NAXJA, figured i'd post it up here.

Went to the LKQ jy in Greenville, and snagged the backing plates, dust shields, backing plate studs and nuts, the calipers, and the flexible hoses. I also grabbed the ZJ e-brake cables, though I ended up not needing them. I also got the wheel studs from the front of an XJ.

The backing plate for the discs is quite a bit thicker than for the drums on the 8.25", so that is why you need the backing plate studs, they are longer for better thread engagement, and the XJ front wheel studs (or any studs from a ZJ) - because the rotor is thicker than the drum.

The setup from a D35 can work, but you need to enlarge the center hole a tad for the 8.25. If you happen to find a libby (which I didnt), it is a direct swap.

The ebrake cables can cause problems. KJ cables are too long, but can be looped and work fine, they have the same ends as the ZJ. The Driver cable from a ZJ works, but the pass side is too short. XJ cables are obviously perfect length, but have different ends. Someone on naxja came up with a nice fix for that which I will show later.

For the brakelines - the ZJ calipers have a separate, short flex hose. The later KJ lines have the flex hose permanently mounted to the hardline, so they won't work. I just used the ZJ lines and bent my XJ hardlines to mate up with them, and they bolted together perfectly.

I didn't take the rotors because they were in terrible shape - got new rotors and pads from Rockauto.com. I also returned the calipers for cores - piece of mind.

Pictures to come tonight when I get back in the garage. I am a little over half way through. One side is complete, just need to finish the other, replace gear oil, and bleed.

Stay tuned.
 
#2
So this is a pretty common mod for XJers and on NAXJA, figured i'd post it up here.

Went to the LKQ jy in Greenville, and snagged the backing plates, dust shields, backing plate studs and nuts, the calipers, and the flexible hoses. I also grabbed the ZJ e-brake cables, though I ended up not needing them. I also got the wheel studs from the front of an XJ.

The backing plate for the discs is quite a bit thicker than for the drums on the 8.25", so that is why you need the backing plate studs, they are longer for better thread engagement, and the XJ front wheel studs (or any studs from a ZJ) - because the rotor is thicker than the drum.

The setup from a D35 can work, but you need to enlarge the center hole a tad for the 8.25. If you happen to find a libby (which I didnt), it is a direct swap.

The ebrake cables can cause problems. KJ cables are too long, but can be looped and work fine, they have the same ends as the ZJ. The Driver cable from a ZJ works, but the pass side is too short. XJ cables are obviously perfect length, but have different ends. Someone on naxja came up with a nice fix for that which I will show later.

For the brakelines - the ZJ calipers have a separate, short flex hose. The later KJ lines have the flex hose permanently mounted to the hardline, so they won't work. I just used the ZJ lines and bent my XJ hardlines to mate up with them, and they bolted together perfectly.

I didn't take the rotors because they were in terrible shape - got new rotors and pads from Rockauto.com. I also returned the calipers for cores - piece of mind.

Pictures to come tonight when I get back in the garage. I am a little over half way through. One side is complete, just need to finish the other, replace gear oil, and bleed.

Stay tuned.
Good tech! We did a similar swap on someones jeep in Clemson using d35 parts. cant remember whose it was though.
 
#5
So to start, first jack up the jeep, remove the wheels, and pull the drum. Then drain the diff, remove the cover, and remove the bolt holding in the cross shaft. Then push the axle shafts in and pull the c-clips. Then you can pull the axles. Once they are out, you can remove all the drum bullshit.
1353455407.jpg

Leaving you with this. I immediately bolted up the loaded calipers to minimize brake fluid lost.
1353455433.jpg

Next, I opened up the center hole on the backing plate. Then I pounded out the backing plate studs. Here is a comparison between the studs. XJ are the short ones, and the long ones are ZJ for the thicker backing plates
1353455558.jpg


Then I pounded out the lug studs in the axle shaft and replaced with the Front studs from an XJ. They are longer to accommodate the thickness of a rotor.
1353455546.jpg

Then we have to deal with the ebrakes. Here are the XJ ends.
1353455505.jpg
ZJ ends
1353455518.jpg

The backing plate ends. The two holes i drilled to fit a 1/8" cable clamp, which will be used to bolt down the XJ ends.
1353455530.jpg

And clamped down
1353455576.jpg

Here is the backing plate with ebrake hardware bolted up to the axle.
1353455587.jpg

Next, slide the shafts in, replace c-clips, replace cross shaft, bolt into place, and bolt the cover back up. Fill with fear oil.

Then place the rotors over the axle shafts an backing plates, then bolt up the calipers. Bleed, then test drive. Done!
 
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