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WJ brake/knuckle/steering swap to a ZJ

peej08

NAXJA Forum User
Location
Biloxi, MS
Going to be do the WJ brake upgrade to my ZJ soon and have some questions. First to clear the hub spacer situation up for me; the hub spacer is required in order to clear the axle shafts correct?


Question : Is it possible to swap the WJ hubs over to the ZJ along with the knuckles in order to avoid using a hub spacer? if so would it matter if i used WJ or ZJ axle shafts?
- if this is possible, can i then swap the rear axle shafts for a WJs to get a 5x5 bolt pattern on all 4 corners?

Thanks!
 
Could someone just answer my last question?

I really wanna know if I can go to 5 on 5 because I have a set of rubicon rims and tires laying around.
 
Could someone just answer my last question?

I really wanna know if I can go to 5 on 5 because I have a set of rubicon rims and tires laying around.
 
The axle u-joints have to be aligned with the ball-joints so that there is no binding when the knuckles are turned, and also so that the inner shaft is the correct depth in the pumpkin. Since the outer axle shaft is bolted to the hub unit, the outside edge of the hub unit bearing is what determines the position of the shaft. The WJ and XJ/ZJ/TJ hub units are different in this regard. The purpose of the spacer is to reposition the older-style hub unit on the knuckle so that the final depth of the axle is correct (although you have to use the 00-01 XJ hubs). You can use the WJ hub unit without a spacer, and the final position of the axle will be correct for the knuckle, but it will have 5x5 bolt pattern.

I've done some preliminary research into doing a WJ 5x5 conversion for the rear but have not figured out if it's feasible. The flange on the WJ rear axle is square, as is the bearing retainer plate, and all of the other parts (such as the disc brake backing plate) also make assumptions about that same basic shape. However the XJ, ZJ and TJ all used other shapes and bolt patterns for the axle flange and bearing retainers. In order to bolt the WJ rears onto a ZJ axle you would need to either replace the flange on the axle, or fabricate some bearing retainers that used the WJ square shape with the ZJ rectangular bolt pattern. At some point you would also need to drill and stud your ZJ axle shafts to have a 5x5 lug pattern so that you could use the WJ rotors. [edit--you will also need to verify the distance from flange to rotor is the same as the stock setup so that the axle depth in the pumpkin is correct, and you may need to fabricate spacers to get it right.] Somebody on mallcrawlin put WJ brakes on a Ford 9" axle so this is all technically possible, but nobody has done it for XJ/ZJ/TJ axles that I know of. The difference in the ZJ and WJ rear disc brakes is very small, so most people think it's a waste of time.
 
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The axle u-joints have to be aligned with the ball-joints so that there is no binding when the knuckles are turned, and also so that the inner shaft is the correct depth in the pumpkin.

Yes, the flange spacer needs to be used for these reasons.

Since the outer axle shaft is bolted to the hub unit, the outside edge of the hub unit bearing is what determines the position of the shaft. The WJ and XJ/ZJ/TJ hub units are different in this regard. The purpose of the spacer is to reposition the older-style hub unit on the knuckle so that the final depth of the axle is correct (although you have to use the 00-01 XJ hubs). You can use the WJ hub unit without a spacer, and the final position of the axle will be correct for the knuckle, but it will have 5x5 bolt pattern.

It's actually the back side of the unit hub that determines the axle depth. The WJ and XJ hubs have the same mounting depth on the back side so the spacer would need to be used with either hub. The difference is that the WJ used a CV axle shaft, and the pivot point in the the CV shaft is about .25" different than that of a u-joint shaft. Hence the need for the spacer to line up the u-joint shaft correctly.

You could use the WJ hubs with the spacer and also space the caliper bracket the same to end up with the 5x5 bolt pattern on the front.

As for the back, sounds like you could just have a machine shop re-drill your ZJ rear shafts and rotors to a 5x5 bolt pattern.
 
It's actually the back side of the unit hub that determines the axle depth. The WJ and XJ hubs have the same mounting depth on the back side so the spacer would need to be used with either hub. The difference is that the WJ used a CV axle shaft, and the pivot point in the the CV shaft is about .25" different than that of a u-joint shaft. Hence the need for the spacer to line up the u-joint shaft correctly.

Thanks for the correction
 
My understanding is that it's the inner C that is shallower than the XJ/TJ/WJ/YJ D30 for use with the CV shafts. You'll still need the hub spacer with the WJ hub, and will need 1/4 inch caliper spacers to compensate.
 
Thank you guys, I can't post on mallcrawlin (tech section) until I reach 100 posts. I will look into a machine shop around my area and see what they say.
 
I ran by the parts store on my way home today to get some measurements on some other parts, while I was there I compared a WJ and '00-'01, XJ hub. They both have the same mounting depth into the knuckle and will both put the shaft in the same place. You will definately need the spacer with either hub.
 
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