Musings from kb8ojh.net

Identifying damaged parts

The most often-fingered culprits for the Death Wobble in a TJ Wrangler seem to be:

• Worn ball joints
• Damaged or worn steering dampener
• Worn track bar end or bushing
• Worn control arm bushings
• Poor wheel balance
• Bad alignment

I have had two sets of tires on my Jeep since it developed the Death Wobble (which, by the way, was during the warranty period, and Chrysler claimed they’d never heard of it — despite thousands of references to it on the Internet, videos of it in action, and my Jeep experiencing it, which, of course, they “couldn’t replicate”), and had it aligned twice, so I knew those weren’t the fundamental culprit. The most likely problems in my case were therefore ball joints or the track bar.

Getting under the Jeep to figure out what I might need to replace, I found that the lower driver’s side ball joint could be moved with a pry bar — not a good sign. The tie rod and drag link were also both obviously worn out (they could easily be moved/rotated with one hand). The track bar is not easy to check without removing it, nor are the control arm bushings or steering dampener.

In addition to the items I could tell were worn out, the sway bar links are often casualties of the Death Wobble, and the steering dampener was almost certainly bad after numerous Wobbles. So I put together a list of about $600 in front end components, and ordered them. I purchased mostly OEM-equivalent components, not off-road upgrades:

• Drag link assembly
• Tie rod ends
• Steering dampener
• Track bar
• Polyurethane track bar bushing
• Sway bar links
• Polyurethane sway bar bushings
• Upper and lower ball joints
• Upper and lower control arms
• Upper control arm axle bushings

Both the track bar and drag link have tie rod ends made onto the bar itself, so they had to be replaced even though only their ends were bad (or presumed so, in the case of the track bar). The track bar comes with a rubber bushing pressed in place, but I bought a polyurethane bushing to replace it. Furthermore, it took some doing to figure out the situation for the control arms; the lower control arm has two of the same bushing, and the upper control arm is sold with one bushing installed and requires the front bushing to be purchased separately, at least from Quadratec, where I was ordering. The lower control arm bushings can be bought separately or with a new control arm for very little more than the cost of the bushings, so I purchased the entire assembly.

Initial disassembly and steering linkage

When the parts started arriving, I put the Jeep up on jack stands (near the body mounts just behind the front tires, supporting the frame), took off the tires, and pulled apart the steering linkage. You’re going to want to take some measurements when you do this, so that you can get things together close enough to get to the alignment shop (or close enough to ease alignment, if you’re doing it yourself). Measure the distance from the end of the tie rod to the center of the bolt (or grease zerk) on each tie rod end, as well as the center-to-center of the two end bolts, then repeat for the movable end of the drag link. Write this all down, it’s going to be a while before you get to it again!

On my Jeep, all of the bolted parts came apart with comparative ease, nothing was substantially stuck (except some cotter pins), and nothing broke (except the aforementioned cotter pins). Your mileage might vary, there, depending on climate, storage conditions, and damage from off-road activity. My Jeep has lived in a garage for most of its life and its off road activity is limited to trail rides (no rock climbing or river fording here), so things weren’t in terrible shape down there.

With the steering linkage off, the steering knuckles (the bit the wheel hub mounts to) are free to rotate back and forth, making disassembly easier, so I removed the brake calipers and rotors. When you remove the calipers, set something by the frame to support them; I used some buckets and boards. They shouldn’t put tension on their brake lines, and they’re going to be there for some time. At this point I had to go buy my first “oops” part — a 1/2"/13 mm spline socket for the wheel hub bolts. They’re either 12 point or spline, but the spline socket worked great. Fortunately a friend had the 36mm axle nut socket, so I didn’t have to buy that. Once I had the tools, I got the wheel hubs off without difficulty. Miraculously those spline bolts were not siezed (they looked terrible), and came right out. siezed, and the

At this point the narrative order gets a bit muddied; I definitely took the passenger side wheel hub off one day and the driver’s side wheel hub off the next day, but I don’t remember what (if anything) I removed in between. I think nothing. Either way, it turned out that a) both wheel hub bearing seals were leaking, so I needed two new wheel hubs (it’s a sealed, non-repairable unit, about $63 each); and b) no local parts store had two wheel hubs. I bought one each at two different stores and called it good.

Ball joints, sway bar, and reassembly of steering

With the wheel hubs off, the U-joints and half axles literally pull right out. My U-joints seemed to be in good shape, so I just set those aside. This leaves the steering knuckle mounted on the ball joints and ready to be removed by removing the ball joint castle nuts. A few swift raps with a 3 lbs drilling hammer (the best hammer ever: Estwing B3-3LB Drilling Hammer) knocked each knuckle off the ball joint tapers. At this point the ball joints can be inspected properly; both of my lower ball joints were completely destroyed, and flopped around in their housings like a ball-in-socket. The upper ball joints were still pretty stiff, but I elected to replace them anyway. The amount of play in the lower ball joints when prying them with the frame lifted but everything assembled versus the amount of play in the disassembled joint was shockingly (to me) misleading; I would not have guessed they were so bad, from the assembled movement.

Removing the ball joints with a rented ball joint press was somewhat complicated, as the receiver rings supplied with the press were not quite appropriate sizes and the press was not deep enough to place a ring on both sides of the bracket (which would have been required for replacement of the lower ball joint and both removal and replacement of the upper). This required some jury-rigging. The lower ball joints were relatively easy to push out, except that the press had to be mounted a bit crooked. The upper ball joints I then pushed out by the stud; the passenger side ball joint separated (and the stud came out entirely) by this method, allowing me to push directly on the ball joint body without a ring. The driver side joint pushed out by the stud!

Replacing the ball joints was more difficult than removing them, for the same reasons. We put the lower ball joints in first, which may have been a mistake; it’s not clear which order would have been easier. They could be pushed most of the way in without a receiving ring on the back, which allowed enough throat in the press to put a large socket on the back to receive them. The press plates and rings would not have fit. The upper ball joints took a lot of head-scratching and fiddling, but ultimately we were able to get them in by placing the smallest ring available for the press directly on one side of the press (which was OD sized almost exactly the same as the ID of the ring, so separating them after the fact was rather … enjoyable), saving the depth of an end plate, and shimming the other side with a piece of metal plate and a screwdriver tip to get everything straight. It took four hands.

Installing the ball joints was the second most difficult part of the whole job; it took maybe two or two and a half hours. Once they were in, re-installing the (cleaned, primed, and painted) steering knuckle was easy. Before re-installing the steering linkage, however, it seemed prudent to do the sway bar links and sway bar bushings; both were trivial. My only note here is that I couldn’t find any torque numbers for the poly sway bar links; a call to the manufacturer (Crown) confirmed that they require OEM torque (70 ft-lbs for the lower bushing and 40 ft-lbs for the upper joint). The steering linkage was not difficult. The steering dampener did require rocking the wheel back and forth a bit, as the bolt (installed to the drag link) was not precisely at 90 degrees to the bushing in the dampener.

Track bar

Removing the track bar was not difficult. Re-installing it did require pulling the axle toward the driver side of the vehicle, which we accomplished by way of a ratcheting tie-down strap. Removing the factory bushing was straightforward with the ball joint press, and the polyurethane replacement bushing can be inserted by hand.

Wheel hubs and brakes

With the steering knuckles and linkage back in place, the wheel hubs could be re-installed. As previously mentioned, I had to replace both hubs. I elected to clean and paint the shields that mount behind the hubs to protect the back side of the brake rotors before re-installing the hubs over them, as well. Bolting the hubs on was as easy as taking them off, with the most difficult part being putting 175 ft-lbs on the axle nut.

At this point, it did become obvious that the grease zerks supplied with the lower ball joints are unusable. They were tall 45 degree affairs that interfered with the U-joint. The passenger side sheared without any commotion (I didn’t even notice), but the driver side stopped the wheel from rotating and I briefly thought there was a problem in the half-axle or differential. Once the offending zerk was located and both sides were replaced with simple caps, the problem went away.

Control arms

In order to keep the axle in place as much as possible, I elected to replace the control arms one at a time. Because I was replacing the arms along with the bushings, I didn’t have to push out the lower arm bushings or the upper arm frame bushings, and the new arms came with these bushings pre-installed. Removing and replacing each lower control arm in turn was straightforward, although re-installing the bolts required jacking up the axle on the installation side and pulling it to the rear with a ratcheting tie-down.

Removing each upper control arm was similarly straightforward. Removing and replacing the upper control arm bushings (specifically the driver side upper control arm axle bushing) was the most difficult part of the whole job. This was due to a combination of the unsuitability of the ball joint press for the job and the difficulty of reaching the driver side ball joint due to interfering parts (such as the coil spring, pitman arm, and drag link; in retrospect, replacing this bushing before installing the steering linkage would have been somewhat easier). The passenger side bushing was easier than the driver side bushing due to the construction and geometry of its bracket (it’s a U-shaped sheet metal bracket, versus the driver side bracket which is cast into the differential housing, and the bushing presses almost all the way through it, allowing the control arm to be used for final seating). However, I did bend the bushing bracket slightly removing the bushing; I’m not sure how one would press it out without doing so, actually. It did not bend far, and straightening it was not difficult, and I do not believe it to be worse for the wear.

The passenger side bushing was pushed back in with a combination of the ball joint press to get it started and the control arm itself with large washers and some light blows against the bracket to do final seating. I wouldn’t recommend this method, necessarily, but it worked and it was easier than the other side.

The driver side bushing couldn’t be pushed out because there was no way to get the press on it square enough to move it substantially. Removing it was therefore a combination of burning the rubber (with a propane torch), pushing out the center metal bushing, then cutting, crushing, pulling, twisting, and otherwise brutalizing the outer metal shell until it came free. This was the single most time consuming task of the entire job; it took approximately two and a half hours. Re-installing it likewise could not be done with the press, so we employed the press receiving rings, a large socket, a number of washers and nuts, and a long piece of threaded rod to press it into place. Getting it started square with the hole was tricky (for one thing, the hole in the bracket appears to be neither square with the ground nor parallel to the front-back axis of the vehicle), but by witnessing it both from the front through the steering linkage and from the top past the steering fluid reservoir and employing judicious blows from the 3 lbs hammer (another two-person job), we got it started. Once it was started, it was simply a matter of cranking down on the threaded rod until it broke (we could get neither grade 5 nor grade 8 rod on short notice) and then finding a fresh part of the rod where the nuts would thread on and starting again. All told, it was much easier than removal, but still time-consuming.

I found that re-installing the upper control arms was easier if the axle end bolt was pushed in first, as the front of the control arm itself has more play in it than the rear (as the rear has a bushing pressed into it holding it rigid, while the front is a loose U until bolted in), allowing the rear bolt to be jimmied into place by bearing on the control arm. I believe the driver side upper control arm also required some ratchet strap treatment, although I do not fully recall.

Final assembly and alignment

With the steering linkage assembled and the control arms replaced, the tires can be remounted and the Jeep set back on the ground. I tightened the sway bar bushing bolts after setting it back down, then checked the various fasteners that do not have a cotter pin (sway bar links, control arms, steering dampener, etc.).

I had alignment done by a professional shop. The driver’s side wheel was not toed in quite far enough, but other than that everything checked out. Getting to the alignment shop was not an issue. Measuring the tie rod ends and reproducing those measurements worked great; my suspicion is that the remaining alignment problems were from the previous alignment correcting for destroyed lower ball joints (as it was last aligned after the Death Wobble had taken hold). Measurement error is of course also a possibility.

Lessons learned

It took about four days for this job. I started on Friday afternoon and finished late on Monday, skipping only Saturday morning due to other commitments. I think if we did it again this coming weekend, it would take about two days. It’s a big job no matter how you slice it, and it’s going to be a lot easier with two people; in particular, getting the ball joints and upper control arm bushings pressed in will be easier with an extra pair of hands. Most of the other operations can be done solo with a minimum amount of difficulty, but not having someone to “hold the other end” or hand you tools will slow you down.

The biggest non-equipment lesson taken out of this is order of operations. I wanted to get the steering linkage completely in place before doing the control arms in order to minimize the possibility of anything coming too far out of alignment, but in retrospect it would have been much easier to deal with the upper control arm bushings (particularly on the driver side) with the steering linkage removed. I don’t think there’s any reason not to do this. The steering linkages are all flexible anyway, and the track bar and remaining control arms (assuming they’re replaced one at a time) will keep things where they belong.

As far as equipment, I had seen several comments that the typical ball joint press that can be rented at local auto shops doesn’t really have the right fittings for a TJ Wrangler. There are kits available to adapt those presses for Jeeps, and there are presses for Jeeps. They are relatively expensive; I am not sure I would purchase one, but I might call around to local shops and see if I could find one to rent. The shop I rented the press from did have adapter kits for some vehicles (mostly imports), but not Jeeps.

Total costs

The total costs were as follows:

Several of these parts are available cheaper, but I wound up paying more either to get them in time or to consolidate orders, or because I didn’t trust some sources (e.g., the entire steering linkage is available for just a few dollars more than I paid for the drag link … and possibly made of cheese?). In particular, I bought the tie rod ends locally, which cost me about $20 more than ordering them with the majority of the rest of the parts, but Quadratec didn’t have them in stock.

While I did preorder most of the parts without knowing if they were absolutely required, when all is said and done I don’t think I replaced a lot of things that didn’t need to be replaced. The upper ball joints may have been OK, as may have been the control arms themselves (but the bushing rubber wasn’t in great shape). However, I don’t think I would change the lower ball joints without the upper, and the upper control arms were sold as a unit with the rear bushings; I might have been able to save $30 or so by buying lower control arm bushings instead of lower control arms. I could of course have aligned everything myself, but I was more comfortable leaving that to a professional. I don’t think I could have reduced the above cost by more than about $100 in practicality, except maybe by vetting some of the cheaper parts suppliers for legitimacy and ordering from multiple sources.

Results

So far, it seems to have worked. I’ve driven several problem roads with nary a Wobble, and no pre-Wobble vibrations. The steering is much stiffer and more responsive; I attribute this to three things: 1) the old parts were worn, 2) the new parts haven’t yet broken in, and 3) replacing rubber bushings with polyurethane in several places. All in all I like the feel much better than what I’d grown used to!

Acknowledgments

I had a lot of help on this one. One friend spent about 2 1/2 of the four days here working in my driveway, and my dad dispensed a fair amount of advice over the phone (he has an XJ, which has a very similar front end).