I was on another thread discussing this but I have a little more data now. I purchased a '99 XJ. It currently has a CAD front axle. I received a donor HP D30 with the purchase of the Jeep. I am in the process of rebuilding it to replace the CAD that is in it now. The HP D30 is a mfg date of 11/98 so it's close enough to my 03/99 mfg date XJ that I could call it original.

The donor is missing one steering knuckle, the pinion yoke and both hubs. I was told that none of the stuff from the CAD will fit the HP D30. However, the previous owner replaced the hub assemblies on the CAD axle in mid 2021 and he said he ordered assemblies for a '99 Cherokee(Raybestos PN 713084). Wouldn't that mean they should fit my HP D30?

I really don't want to spend several hundred dollars on parts if I can use them from the CAD axle. I doubt that I can get much for a complete CAD. But if I'm wrong and I can sell it $150-200, I am happy to do that and take the proceeds and buy new hubs, knuckle and yoke.

The yoke is not a biggie as I may upgrade to the u-bolt type. But the knuckle and hubs would save me quite a bit.

 

as far as i can remember hub wise they are all the same. the tricky bit is the knuckles themselves. While the knuckles for an early XJ axle will direct mount into a late xj axle the difference comes with the brake caliper setup and how they mounted to either year range steering knuckle. I forget which year it changed but i would guess it to be around 89-91. This also came with a slight change in hat height of the rotor as well. The yoke's should be all the same. Im sry this is a little bit of fog info and not crystal clear #'s but this might get you in the direction your trying to go.

 

if the hubs are already for a 99, then they should work on the HP axle. I didn't know when you said they were new that they were the '99 ones.

 

Just looked some of this up in https://www.cherokeeforum.com/f2/89-...rotors-265440/
Hub height and rotors changed in 1990. Calipers, knuckles stay the same.

I believe the switch between cast and composite rotors and hub height happened mid-year in 1999, so you really need to measure to be sure.

 

I will check the steering knuckle on the CAD and compare it to the one I have on the HP. If they are the same I'll use it. Looks like the hubs and yoke are good to go. As far as rotors, I'm not sure the condition of the rotors on the CAD but if they currently fit the hubs, they should also be fine. But if the rotors are going to be replaced if I buy rotors for a '99, I should be good there also. I'll measure the hubs to confirm early or late.

The goal is to end up with the proper components for a '99 when I complete the diff swap.

Am I on the right track?

 

Follow up for those that may be interested: the knuckles are the same so I took one from the CAD to use. The yoke is the same but has some scoring. Not sure if I should use it as is, sleeve it or buy new. What are your thoughts?




Hubs are the same and the new rotors I bought are cast. The rest of the brake components are the same.

However, one of the axle stubs on the HP D30 have some thin threads at the end. I can still thread on the nut and it ends up on good threads but I thought I'd grab a stub out of the CAD axle. Upon examination though, the CAD version has a smaller "cross" than the HP. Less steel. Hmm...

 

huh, I thought all CAD axles got those weird 2 part knuckles. Learn something new everyday apparently.

 

I will be posting up a picture of the brake pad/caliper interface with the knuckle to see if I need to have it welded up. There is wear on a portion of it. I'm not sure how wear necessitates a weld up.

 

Here is the pic of the knuckle. Shows some wear. Is it enough that I should have it welded?

 

yeah cause the pads could get hung up and wear weirdly/loose braking power.

 

or get wedged, they should be welded up and ground smooth.

best to preheat best as possible and MIG them up

 

Thanks. What about the area looking at the pic on the top right portion? If you look closely you can see a slight dip on the edge that is perpendicular to the portion that has the divot on it.

 

Definitely preheat any cast part. I would weld the dip and regrind the surface. Brakes are good to have......