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Hi all, this post is to document my WJ upright and brake swap on my 1999 XJ.
There are lots of how-to's on this swap, most involving custom steering arrangements that really drive up the cost and time involved. My goal for this was to reduce the amount of fabrication and design choices to a bare minimum. No crossover or high steer setups, no heim joints. I want factory style parts for ease of maintenance and parts sourcing on a light duty Jeep.
I used the following components:
Wheels that clear the larger calipers - 16" or larger recommended
WJ uprights, any year
2003+ Akebono brake calipers
0.25" hub spacers
Timkin HA597449 front wheel hubs for 2001 XJ
WJ rotors redrilled to XJ bolt pattern
WJ Ball Joints - Dana 707488X contains two ball joints (one upper, one lower) and will service one side of the axle.
ZJ Pitman Arm - Crown Automotive 52005285
All new consumables like caliper rebuild kits, pads and pad clips, etc.
Anyway, lets get into it!
Checking the clearance to the 16" wheels.
Some measurements showed the WJ uprights to have the tie rod locations about 0.9" - 1" lower than the XJ tie rod locations. I'm not going to pretend this was a perfect measurement, maybe someone else has more accurate numbers. This picture seems to exaggerate the difference.
These are the measurements I took of the XJ and WJ uprights, if you're curious.
While I was rebuilding the calipers, I measured the pistons of the WJ and XJ calipers to determine the change in brake bias from this mod.
A ZJ pitman arm gives a 0.75" drop over the XJ part. The ~0.25" difference isn't perfect, but close enough for me. If anyone can point to a 1" drop pitman arm, that would be perfect for this swap.
Midway through 1999, the XJ brake rotors and wheel hubs changed dimensions. Later version on the left, earlier on the right. As long as you keep the rotor and hubs matched, you can swap with ease. For the WJ swap, you need the later hubs.
All the parts prior to welding. A friend of mine has a CNC machine, so I had him cut out the 0.25" spacers. An old 2wd wheel hub was knocked apart and degreased to use as an alignment jig. The center hub bore helps locate the bearing hub, so yes, you need to do a good job of welding it on.
After bolting them together, it went into the oven at its max temp for an hour. Note that I sandblasted the entire upright for cleanliness. The spacer was welded on, then allowed to very slowly cool in the oven for several hours. Some people will only heat the upright and spacer, and bolt on a hub after pulling it out of the oven. That's a great way to waste time and heat. Just use some sacrificial hub housings and bolts.
Post welding. Not my best work here… oh well. It should hold.
I ground down the welds a bit and painted the uprights. Probably should have left the welds alone, oh well.
I ordered Timkin hubs for a 2001 XJ, and found that this perfectly centered the WJ rotor in the caliper. I did not need any caliper spacers as I've seen in some guides. My friend again used his CNC to redrill the WJ rotors to the XJ's 5x4.5 bolt pattern.
Now, just put it all together. Install the WJ ball joints in your axle, and the ZJ pitman arm onto your steering box. You're now able to treat everything that follows as basically stock parts. Refer to XJ and WJ service manuals as appropriate for torque specs and more detailed instructions.
Clearance to the wheel when on the Jeep. Note that I used an old ball joint center to keep the WJ drag link taper nice and clean, in case I ever want to convert to crossover high steer.
What it looks like from the outside. What have we got here... WJ brakes/uprights, WJ control arms, YJ brake lines, ZJ springs, and some other goodies that are definitely not original to this chassis.
Other notes:
Factory XJ 15" wheels will not fit. The smallest wheels a WJ came with are 16"s. Some aftermarket 15" wheels may work, but I cannot help with that.
There is a change in the XJ hub dimensions mid-year in 1999. I ordered hubs for a 2001 to make sure they were the later style.
Don't get the Teves calipers with a retaining wire that are in earlier model year WJs, they suck and have a service bulletin out for their replacement with the Akebonos.
If you got junkyard calipers, rebuild them. It's very straightforward even with the dual pistons, and extremely cheap.
The front brakes will be about 15% more powerful after the swap if my math is right. I have not done anything to deal with the proportioning valve as part of this swap. I do also have ZJ rear discs, and the proportioning valve to match them.
The ZJ pitman arm is to bring the drag link angle back (closer) to factory specs and match the track bar angle. Everything will bolt up with an XJ pitman arm, but you're more likely to get bump steer. The ZJ part is only a 3/4" drop, a 1" drop arm would be the perfect part.
Supposedly, the WJ brake banjo bolts are located about an inch lower, but I did not measure to confirm this. If your brake line length is marginal, you may need longer lines. I have YJ lines on my XJ to match the 3" lift and they work fine.
Your front brakes can now be treated as if they are that of a 2004 WJ Grand Cherokee. If you need help with pad selection and determining which pad clips you need to buy, this swap is not for you.
This isn't meant to be an end all, be all source. If it's not in the post, I probably can't help. I don't know if your aftermarket 15" wheels will fit, I don't know about your desired custom steering setup, I don't know if your different wheel bearings will work, I don't know how you can perfectly drill out your WJ rotors with a hand drill, etc etc.
Lastly, the traditional warning that I take no responsibility for what you do with this info or what you do to your Jeep. Use your own brain when screwing with important safety systems like brakes and steering. Professional driver, closed course, don't copy me, etc etc.
Last edited by OptionXIII; 02-09-2021 at 09:22 AM.
The pedal is definitely much more sensitive now. Combined with the ZJ rear discs and it's a night and day difference compared to my unmodifed XJ. That said, I've got very few miles since the swap, as the Jeep is a long term project.
I did this swap a year ago, but I don't recall any difference in the length of the tie rod mounting point. So there shouldn't be any need for a longer pitman arm.
You not having issues with turning radius limited is good to know.
I am only asking because I am comparing xj to zj pitman arm as equal length with a drop below but the wj pitman arm is longer.
I am doing a similar swap but want to use the upper connection with a raised pitman.
Yj and wj have the same drop but wj is longer. Both are a raise up from stock xj.
Yes, the standard WJ drag link location definitely has a shorter arm, so you would need a longer pitman arm to get the same steering angle out of a given steering box angle. I gave up on trying to figure it all out as I have a bunch of other work to do on this Jeep, and figured this would be a good intermediate improvement.
Let us know if you find something that works well! I still want to go crossover eventually with a raised pitman arm just like you describe.
Last edited by OptionXIII; 02-09-2021 at 08:35 PM.
02-07-2021, 02:25 PM
WJ Brake Swap, on the cheap
