4X4NOW Buildups - Sam Houston's '98 Jeep TJ Part III

After promising Wayne forever that I would provide some updates into the buildup of my TJ for 4X4NOW, I am finally doing it a year or so since my last update (the Kayline top install). Since then, I've put about 7,000 miles on the odometer (about 1,000 of them off-highway) and I've put about 3,000 mile on the TJ flat towing it behind either a ZJ or Dodge Cummins 4x4. During this time, I have consistently upgraded the Jeep, broken a few parts, and fine-tuned what I have. I'll try to cover these learnings / upgrades in chronological order.

On my first ride, I noticed that the 15x8 inch wheels with 4 inch backspacing on my 33x10.5 Swamper radials caused the tires to stick out past the factory flares and did not provide any protection for the rims. Even worse, I really could not air the tires down as far as I would have liked for fear of popping a bead. This was solved with a little research into American Racing sizes and backspace availability. I ended up with the same style steel wheel in 15x7 with 4.25 inch (I'm working from memory ... it's either 4.25 or 4.5) backspacing. This turned out to be the perfect setup for my tires and Jeep, keeping the tires under the flares until I added a Warn hub conversion (more on that later).

It didn't take me too long to realize that the Rancho RS5000's I initially installed were too long (Part number 5010s). Both the front and rear shocks would bottom before the bump stops contacted and they allowed too much droop ... yes you did read that right. In the front, the lower control arms would bottom out on the axle brackets. I caught this when I noticed that the powder-coating had been chipped off of the arms. Luckily, I caught this before any real damage was done to the control arms. I then checked the rear ones and found that they allowed so much droop that the rear driveshaft would start to bind and the coils got real loose in their mounts.

After some careful measuring, I gave Greg at Jim's Off Road a call with compressed and extended length targets and got what I needed ... Rancho RS900s, Part number RS9168 for the front and RS9118s for the rear. At this time, I also added JKS bar pin eliminators to the front (I tried to add them on the rear as well, but my TJ did not have enough room for them due to manufacturing tolerances). These shocks worked great until I beat the knobs off the rear shocks and I added a JB Conversions tail shaft kit that allowed for more rear droop. Now I am running RS9124 shocks in the rear in a can-up position. These allow for a bit more droop in the rear while maintaining acceptable compression. The rear shocks now hardly ever get adjusted :-)

During a May, 1998 trip to Tellico, I managed to come down HARD on a rock and put a nice gouge in my front driveshaft. When I noticed that the CV centering ball was bone dry (after only 5,000 miles) I understood where the rhythmic squeaking I had been hearing had come from every time it rained. A quick phone call to Six States got me a new heavy duty front driveshaft. The emphasis here should be on heavy ... the Six States shaft is smaller in diameter than the stock one, but is 75% heavier as well. Plus it is greaseable

On the way to Tellico, I had stopped at Jim's Off Road and was BSing with Greg who told me that Warn was developing a lockout kit ...was I interested. My famous last words were "Nahhh ... I'm OK the way I am now." Well, after shaking a while and burning myself and uttering enough profanity to earn me a few weeks in purgatory while removing the mangled front drive shaft, I was seriously contemplating this conversion. When I fuel economy improved almost 2 MPG for the trip back to Ohio over the trip down and the only difference was no front driveshaft freewheeling, I was more serious. bu98tjea.jpg (9462 bytes)

When I found out that Warn would offer a lifetime warranty on the components, I said what the hell. So I placed an order for the first 5 on 4.5 inch hub kit they got their hands on. I'll admit to paying them to install the kit, but I do not regret it as the charge for the install was quite reasonable. This modification has been flawless to date, I only wish that Warn had been making their inner axles at the time I ordered the kit.

bu98tjeb.jpg (9208 bytes)
In this picture, the new springs, coil spacer, and Rubicon Express control arms are visible.

For the next several months, I did a little 'wheeling and a bunch of road driving as I moved myself and my wife from Ohio back to middle Tennessee. But the Jeep was great and drove well. In early 99, the rear springs, which had always caused the Jeep to sit tail low started sagging noticeably. In the course of 5 weeks, I measured a drop of almost 3/4 of an inch down to a net lift of 1.75 inches with the hardtop on and loaded with tools and spare parts plus the rear of the Jeep wallowed badly over bumps. A quick call to Jim's and the hard top springs were on their way at no cost to me. 30 minutes with a friend helping and the old springs were removed and new ones installed. This raised the rear back to the original level (slightly tail low) but improved the handling tremendously. The Jeep had never driven so well since I had lifted it But more height was needed to level the TJ. The next time the axle was out of the Jeep, a set of coil spacers were added (1.75 spacers were used since more weight was added to the rear). Now the Jeep sits level and drives great.

During a ride in late February, I started hearing popping and snapping noises coming from the rear axle of the Jeep under torque reversals at first, but later whenever a turn was made. A quick blip of the throttle in a muddy spot while in 2wd with the ARB locked showed that I had not broken an axle. A similar blip of the throttle with the ARB having been "unlocked" for about 10 minutes revealed that the differential was still locked. Further diagnosis reveled that the ARB was pressurizing and depressurizing fine, but it was not unlocking and it was doing a good job of imitating the noises that Detroits are known for. Oh, well ... if it had to break, at least it broke in a locked position so I can keep 'wheeling.

A week or so later, the ARB was removed and shipped back to ARB - USA for diagnosis and repair. However, the Jeep is still my daily driver and I could not afford to be without a vehicle for the time it took ARB to receive my differential, determine what was wrong, fix it, and return it to the shop. So I had a Detroit installed and was back on the road relatively quickly. The problem ended up being a bad air piston and a chewed up locking gear. To ARB's credit, they did warrant the locker even though it was technically out of warranty. My only problem was not having a standard carrier available to put in the Jeep and run for 3 weeks and not wanting to have to pay to have the rear end set up twice in a 4 week span. The Detroit in the rear IS noticeable on the street, but livable.

When the ARB broke, my wife asked me "How much is this gonna cost?" My answer was "About $500 or so, but a lot less that what I'll have done while it's in the shop." The reply from her was "Oh s--t!, What are you doing now?"

While the Jeep was at Jim's Off Road, I went ahead and bit the bullet on lower transfer case gearing and a fixed output yoke conversion. I had wanted to do an Atlas II conversion, but the prices keep going up and up, so I rationalized and realized that I can almost do 2 TeraLow / JB Conversions swaps (including buying a second NV231) for the cost of an Atlas II conversion. It's done and it works fine.

I also tried to save some $$$ and use a conventional driveshaft. I am here to tell you that it can be done, if your Jeep is a trail Jeep. After some control arm adjusting on my part, I got rid of all the driveline vibes and my 15 9/16" driveshaft was running smoothly, but with 14 degree operating angles on the u-joints. This kind of operating angle is not conducive to long u-joint life. bu98tjed.jpg (11691 bytes)

I have ended up with a Six States CV driveshaft. After rotating the pinion up (using Rubicon Express control arms I purchased directly) my static u-joint angles are 1/2 degree at the pinion and 10 degrees for the CV unit (5 degrees per cross).

I did a little quick math that helped me in my initial (and only) upper control arm length setting that I will share. (NOTE: I know that this calculation is far from exact since it assumes a right triangle, but with the angles and distances involved, it was a good approximation, and I could not remember the Law of Sines or Cosines off the top of my head. I saw this to keep from being flooded with e-mails correcting me from other engineers.).

I started after I had adjusted my lower control arms back to their starting length. I first took some measurements of flange angles with an angle indicator, then I bolted in the new driveshaft and measured the angle of the driveshaft.

Guess at what driveshaft angle will end up being after pinion rotated up = 17.5 degrees

When I set the upper control arms to 5/8" (0.625) longer than the stock arms, I ended up with a 16 degree driveshaft angle and a 15.5 degree pinion angle and a smooth running rear driveshaft (no DRIVELINE vibes up to 80 MPH ... definite out of round Swamper shakes though).

Also added was a Runck rear bumper at this time necessitating the taller than expected coil boosters. I installed the Runck because it provides some body side protection and it is hell for stout. I still think that the Cross Enterprises bumper is a great design, but I was enticed to give this bumper a try through an incredible (discounted) price. This bumper / tire carrier combo is HEAVY though ... almost twice as heavy as the previous bumper. In using this bumper, I have given up ease of opening and the ability to add an integrated rear rack for the benefit of a wrap around design providing some body side protection. The pictures below show this bumper from a couple of different angles.

As mentioned above, I added Rubicon Express's adjustable upper control arms to the rear of my TJ. This allowed me to more easily adjust my pinion angle. While installing these, I found that all that is needed is to raise the rear about 3 inches with a floor jack under the axle and put jack stands under the frame right in front of the lower control arm brackets, then lower the rear axle so that the tires are supporting it. You can the remove both upper control arms with out any problem. If you are rotating the pinion up, a bottle jack under the front of the differential is helpful for installing the upper control arms.

While removing the passenger side upper arm, I discovered that the frame bolt was not as tight as it should be. (All the other bolts were at factory torque specs). I also discovered a way to get a torque wrench onto this bolt without removing the muffler. Since I was using new factory bolts, I had a plain nut left over (as opposed to a tab nut) and I used it instead of the tabbed nut. There is an access hole through the frame (at least on my TJ ) that allows you to get a socket on the nut (you will probably have to remove the tire). I applied red locktite to this nut and torqued it to factory specs. Hopefully this will prevent loosing but I'm going to make these bolts a more consistent maintenance check. This bolt was apparently the cause of a mysterious clunk and some unusual handling characteristics.

I also have installed an adjustable front track bar from Rusty's Off Road. This bar is unique in that it uses a common tie rod end for the frame end (it's a Jeep CJ tie rod end) so that spare ends are easy to find and cheap. Installation is a snap and it eliminates adds some extra droop to the right front wheel since in my case, the track bar was bottoming in the axle bracket causing the passenger wheel to have about 2 inches less droop than the driver's side. Rusty's is also in the process of releasing an adjustable rear track bar which will be a godsend for those folks who have had to rotate their pinion up. On my TJ, the rear track bar rubs the gas tank skid plate (factory one) and has the bushings in a real bind. I have no doubt that the bushings will not last long given the out of alignment condition between the track bar and the axle and frame brackets. I will report on this bar as soon as I can get my hands on one.


These two shots show the Rusty's Off Road adjustable track bar (the silver colored bar) and how it connects to the frame and axle.

Also installed was a steering gear brace from Rusty's. The install was straight forward, except for tightening the nut inside the frame on the forward hole.

Gotta love my wife, Angie, who orchestrated the purchase of a Runck front bumper for my birthday present without my knowledge. I had no clue until it arrived with a card from her, my mother-in-law, and my father ... what else can I say, but I gotta keep her. My good friend, Tony, also gave me some much needed longer front brake lines (stainless of course).

The front bumper was a straight forward installation requiring only the removal of 6 bolts, pulling the front bumper, and replacing it with the Runck unit.

The front brake lines are from 4WD Hardware and are made by Goodridge to meet DOT regulations. The lines are about 4 inches longer than stock and have the correct fittings from a hydraulic standpoint, but do not have the same mechanical attachment to the frame as the stock lines. These lines use a fitting similar to CJ lines on the frame end. In order to make the mechanical attachment to the frame, I designed a bracket and had it made. Basically, the bracket is a 4 inch piece of flat stock bent into an "L" with the legs being approximately 1 inch and 3 inches with a slotted hole drilled 2.5 inches up the long leg from the short leg. To this is welded an appropriate sized washer. The stainless line is a tight fit through the washer and is retained in the bracket by an "E" clip. The bracket bolts to the frame using the factory hardware with the short leg going under the bottom of the frame to locate it . The following pictures show the bracket in detail and the completed installation.

Front brake line system using the TeraFlex bracket and the stock line.	Completed installation prior to adding a length of fuel line hose over the lines for chafe protection. A quick brake bleed and the Jeep was ready to drive.
Note the length difference between the stock and extended brake lines.

Bracket that I had to have made so that these "TJ" brake lines would work on a TJ.

After my trips started taking me on more and more trails that had a relatively high risk of a rollover occurring, I got a little more serious about protecting Angie and me in the case of a rollover. After seeing the work of Mark Hackett on several Jeeps, I contacted him about building a cage for me. He agreed and after some discussion and a couple of weeks of weekend and night work, I picked the TJ up with a new cage. All of the factory structure remains, but it has been significantly strenghened. All of the joints are now welded, a cross brace was added between the rear legs (over the back seat), a cross brace added just behind the windshield at the top, two down legs added right behind the dash, 2 spreders from the main bar to the cross brace at the top of the windshield, and a cross brace the front legs at dash top height.