This will be a brief overview of what I did to my TJ front axle to put WJ knuckles on. Especially brief since I took zero pictures during the process, only after the fact. There are certainly several options of how, this is one of them.
Basically, this swap takes the outer knuckles, brake calipers and brackets from a WJ to upgrade the steering and brakes of a TJ/XJ/ZJ. To do that, you need to space the unit bearing out from the knuckle, since the WJ uses a different setup. The spacer gets welded onto the knuckle, and is sandwiched between it and the unit bearing. The WJ also uses a different lower ball joint, so that needs to be swapped also.
The basic parts needed are the knuckles, brake calipers, and brake brackets from a WJ axle. You also need brake rotors and lower ball joints--I bought new on both of these. You'll use your TJ brake rotor as a pattern to drill new lug holes into the WJ rotors, in between the factory holes. (the WJ is 5x5" lug pattern, the TJ is 5x4.5") Then you'll need the knuckle spacers, trackbar brackets, swaybar brackets, and new trackbar/drag link/tie rod.
This is a picture of the parts I made. The 4 pieces on the left make up the axle-side trackbar bracket, then the swaybar mount and knuckle spacer, then the frame-side trackbar mount is the 4 pieces on the right.
Here is the main thing we're after: The two steering arms on the passenger side knuckle, so you can separate the drag link and tie rod. (and have a real, wheel-to-wheel tie rod) You can also see the axle-side trackbar mount, which needs to be altered when you alter the position of the drag link. Separate issue, I also boxed the front of the factory upper control arm bracket, since those are prone to bending if you leave them open on the front. You can also see the end of the swaybar link bracket.
Backside of the axle-side bracket:
Here is the frame-side bracket. It can't stick out too far outside the frame if you want to use a swaybar like an Antirock, or my Teraflex dual-rate S/T swaybar.
This shows the swaybar bracket fairly well. This is the driver's side, and it doesn't need to be so high here. On the passenger side it does need to be up high to clear the drag link. These weld onto the top of the inner knuckle.
In addition to the steering, you get better brakes with this setup. The rotor is about 1" larger diameter compared to the TJ, and the caliper is huge. There is about 1/8" of clearance to my 15" wheel...but it sure stops better than it did before!
One possible downside to this setup, is that it requires a longer pitman arm to get full steering. This is where I messed up a little bit--I intended to use a totally flat pitman arm, and made the trackbar brackets accordingly--but then found out the nut for the tie rod end would hit my radiator. So, I went with this 1" drop arm from a Wagoneer instead. That makes my drag link and trackbar angles not quite matching anymore, but it's still closer than it ever was before.
Also, this pitman is slightly longer than the one I used at first, so the trackbar gets friendly with the tie rod end. That could be fixed just by welding the frame-side bracket a little bit farther backward on the frame. I have adjusted the brackets shown in the first picture so the next one will be closer to correct using this same pitman arm.
On the tie rod--from the factory, the tie rod ends go in from the bottom. If you do that same thing, nothing special needs to be done. If you want to move the tie rod to the top of the steering arms as I have, you will need to use offset ends to get the tie rod a bit further forward....and even then, you'll need to trim the front of the coil spring perch to clear. I used tie rod ends from Teraflex, they are also available from Ruffstuff Specialties. (and you can see them in the pic showing the two steering links)
Let me know if you have questions, or need anything clarified.
Basically, this swap takes the outer knuckles, brake calipers and brackets from a WJ to upgrade the steering and brakes of a TJ/XJ/ZJ. To do that, you need to space the unit bearing out from the knuckle, since the WJ uses a different setup. The spacer gets welded onto the knuckle, and is sandwiched between it and the unit bearing. The WJ also uses a different lower ball joint, so that needs to be swapped also.
The basic parts needed are the knuckles, brake calipers, and brake brackets from a WJ axle. You also need brake rotors and lower ball joints--I bought new on both of these. You'll use your TJ brake rotor as a pattern to drill new lug holes into the WJ rotors, in between the factory holes. (the WJ is 5x5" lug pattern, the TJ is 5x4.5") Then you'll need the knuckle spacers, trackbar brackets, swaybar brackets, and new trackbar/drag link/tie rod.
This is a picture of the parts I made. The 4 pieces on the left make up the axle-side trackbar bracket, then the swaybar mount and knuckle spacer, then the frame-side trackbar mount is the 4 pieces on the right.
Here is the main thing we're after: The two steering arms on the passenger side knuckle, so you can separate the drag link and tie rod. (and have a real, wheel-to-wheel tie rod) You can also see the axle-side trackbar mount, which needs to be altered when you alter the position of the drag link. Separate issue, I also boxed the front of the factory upper control arm bracket, since those are prone to bending if you leave them open on the front. You can also see the end of the swaybar link bracket.
Backside of the axle-side bracket:
Here is the frame-side bracket. It can't stick out too far outside the frame if you want to use a swaybar like an Antirock, or my Teraflex dual-rate S/T swaybar.
This shows the swaybar bracket fairly well. This is the driver's side, and it doesn't need to be so high here. On the passenger side it does need to be up high to clear the drag link. These weld onto the top of the inner knuckle.
In addition to the steering, you get better brakes with this setup. The rotor is about 1" larger diameter compared to the TJ, and the caliper is huge. There is about 1/8" of clearance to my 15" wheel...but it sure stops better than it did before!
One possible downside to this setup, is that it requires a longer pitman arm to get full steering. This is where I messed up a little bit--I intended to use a totally flat pitman arm, and made the trackbar brackets accordingly--but then found out the nut for the tie rod end would hit my radiator. So, I went with this 1" drop arm from a Wagoneer instead. That makes my drag link and trackbar angles not quite matching anymore, but it's still closer than it ever was before.
Also, this pitman is slightly longer than the one I used at first, so the trackbar gets friendly with the tie rod end. That could be fixed just by welding the frame-side bracket a little bit farther backward on the frame. I have adjusted the brackets shown in the first picture so the next one will be closer to correct using this same pitman arm. 
On the tie rod--from the factory, the tie rod ends go in from the bottom. If you do that same thing, nothing special needs to be done. If you want to move the tie rod to the top of the steering arms as I have, you will need to use offset ends to get the tie rod a bit further forward....and even then, you'll need to trim the front of the coil spring perch to clear. I used tie rod ends from Teraflex, they are also available from Ruffstuff Specialties. (and you can see them in the pic showing the two steering links)
Let me know if you have questions, or need anything clarified.
