If you’re brave enough to really wheel your Jeep with its stock steering setup and oversize tires, you’re probably also unfortunate enough to have bent it into tiny little pretzels, stranding you somewhere far from your home or nearest shop. We’ve been in that boat before, gambling on the stock toothpick tie rod and drag link, and it was impressive how much flex those things suffered even on the street. Time, we thought, to get serious about strength. But first, we had a little fun comparing the stock tie rod size and strength to that of our Trail Forged HD Kit.
We cut up our old tie rod to get a look inside (before chucking it straight into the steel scrap bin) and measured 0.868″ OD with a wall thickness of 0.147″. We then compared it to our 1.5″ 0.250″ wall DOM tubing, both MUCH larger in size and thickness but also material strength (50-60% increase), which means that the overall strength increase over stock is somewhere in the 1200-1400% (or 12-14 TIMES) range. We think that’s a pretty satisfactory number. While we’re on the topic of strength, let’s talk engineering for a second.
Here is the formula for the elastic section modulus. Take S times the yield stress of the material and you get the yield moment, or moment when the tube will yield.
R1 is the internal radius, r2 the external radius (d1 and d2 being internal and external diameter respectively).
Translation, outer diameter is the SINGLE largest factor in tube strength, followed by wall thickness, followed by material composition. For example, if we went from a 1/4″ or 0.250″ wall to a 9/32″ or 0.281″ wall, strength increases only a further 5% or so, for a respective 10% increase in weight. Bump that to a 1.5″ solid bar (just plain silly) and for the 20% or so increase in strength, an 80% increase in weight. So the goal is: make a part large enough in diameter to provide necessary strength without going overboard, and make the wall thick enough to prevent denting due to impact. Anything beyond that goes past proper engineering and into just plain unnecessary weight, cost, and excessiveness.
But enough of that, on to the good stuff!
To make the XJ strong enough to handle its upcoming Rubicon and other trail runs, we Wrangled up (pun slightly intended) a brand new Trail Forged HD Steering Kit from the shop and set about installing it.
- Floor jack and jack stands
- Wheel chock
- 3/4″ Socket and impact or wrench
- Pair of dykes or pliers
- Small sledge hammer
- PB Blaster or similar (recommended)
- Pitman arm puller (optional)
- 33mm or 1 5/16″ wrench or socket (pitman arm, optional)
- Drill and 5/8″ drill bit or bridge reamer
- 15/16″ Socket, box wrench, and ratchet
- Torque wrench
- 1 1/8″ & 1 5/16″ box wrenches
- Additional sizes of wrenches and sockets depending on specific application and previous modifications
- Chock rear wheels, jack up front and place on stands. You can support from the body but keep in mind axle droop and how high your stands are, we chose to support under the axle/control arm mounts.
- Remove front tires. We LOVE our Milwaukee Fuel brushless impact for this, the thing has balls! (DON’T tighten lugs back down with this, use a torque wrench please. I don’t want to hear back that you stripped out lugs and studs by going a few ugga duggas too far).
- We suggest hosing down the tie rod connections and pitman arm connection with some PB blaster first.
- Use dykes or pliers to remove cotter pins from castle nuts at both knuckles and at the pitman arm. We also removed the one in the center Y connection so we could remove the links separately.
- Remove steering stabilizer bolt from drag link (if still installed).
- Remove tie rod nuts (ours were 3/4″ and the impact took care of these nicely, we used a box wrench on the pitman arm due to lack of room).
- Hammer side of knuckles a few times and then hit the tie rod stud. Tie rod should pop out. If you intend on saving these tie rods, keep the nut threaded on so you hammer the nut and not the end of the tie rod threads. If they don’t pop out easily, hit the sides of the knuckles a few more times and if all else fails, use a small torch to add a little heat to the knuckle (not the tie rod!).
- Repeat for the pitman arm, a little lube and a few good whacks and it should come. If not, remove pitman arm with a puller to give you more room to work.
- Drill left and right knuckles to 5/8″. We used a 5/8″ bridge reamer that we had at the shop because we have found it self centers a little easier, but a standard 5/8″ drill bit should do the job just as easy. If using a drill bit we suggest starting from the bottom and drilling up to help center the bit in the existing taper.
- Drill pitman arm to 5/8″. Again, we used the bridge reamer. We did this with the pitman arm installed, just be careful of hot drill chips falling on you if drilling overhead.
- Remove metal chips and debris from knuckles and pitman arm.
- Reinstall pitman arm if removed, torque to 185 ft-lbs.
- Begin by installing drag link at the pitman arm. For most standard installations, the heim assembly will go ABOVE the pitman arm. Order is: 4″ bolt and washer, misalignment spacer, heim, misalignment spacer, washer, pitman arm, washer, nut. Do not torque yet. We highly recommend checking axle droop to make sure the heims do not bind under flex, this is especially important on higher lifts and vehicles with a lot of droop travel. If necessary, move heim to below pitman arm.
- Install tie rod below knuckles. If installing OTK, be aware of drag link/track bar geometry and possible bump steer. Standard order on the passenger side is: 5″ bolt, washer, misalignment spacer, drag link heim, misalignment spacer, washer, knuckle, washer, tie rod heim, washer, nut. Do not torque.
- Install driver side tie rod end. Order is: 3″ bolt, washer, knuckle, washer, heim, washer, nut.
- Rotate tie rod up beyond where you want it to stay and tighten jam nuts on both sides. Adjust as necessary for desired position. Repeat this for the drag link, and make sure drag link heims are both rotated the same direction and amount to prevent any bind under articulation. Tighten jam nuts.
- Align toe and steering wheel angle by adjusting heims in or out. Make sure the thread engagement on the heim joints is similar left to right. We suggest a very small amount of toe in for best ride, tire wear, and steering feel. This is a fairly easy job with a tape measure, and an extra pair of hands is very helpful. We like to measure the difference from the front edge of the rim to the back edge of the rim. (Toe in means closer at the front than the back)
- Once toe and steering wheel are where you want them, torque driver knuckle bolt to 150 ft-lbs, and bolt with misalignment spacers to 100 ft-lbs. Recheck torque after driving to ensure they don’t loosen or settle.
- (Optional) Install steering stabilizer with optional stabilizer bracket. Be sure to place bracket in the appropriate position to allow the stabilizer full range of motion.
- Reinstall tires, torque to 100 ft-lbs, and then go wheel!
These instructions are meant to be a general guideline and not a factory certified service procedure. We are not responsible for any failures or issues that may arise in others’ installs.