One morning, the staff here at 4WD&SU was kicking around a few ideas and theories about TJ steering setup. The discussion carried on for quite some time due to the fact that there are so many variations and ideas on the subject. In the end, the consensus was that we should speak with an expert about TJ steering, so we headed over to Dynatrac to meet with Jim McGean.
The front of a TJ is a very busy area because of all the possible positions of steering and suspension components during up-and-down travel and left-to-right steering movements - especially during a good crawl session. Without the right equipment, it is very difficult to fully articulate a vehicle's suspension and determine if the complete steering system is in harmony with suspension movement. The actual stresses of four-wheeling can flex steel control arms, bushings, and joints even more than what was observed during the test, so it's important to allow for this flex when designing a steering system.
Things That Affect TJ Steering
A. What they do: limit uptravel. Tires can also stop travel before bumpstops by hitting the body but not always in all positions (e.g. straight ahead).B. What to watch out for: Don't get carried away. Is that last 1/2 inch of uptravel worth damaging other components? Set bumpstops so they halt the axle before it or the steering components hit things like the oil pan, harmonic balancer, framerails, and so on. Remember: bumpstops will compress somewhat. Make sure the bumpstop halts the axle before the shocks are fully compressed.
2. Shock Absorber Limit Straps
A. What they do: limit downtravel.B. What to watch out for: Be sensible. Once the spring is loose in the seat (has no tension), further downtravel is virtually useless but can cause damage to driveshafts, steering rod ends, and control arm bushings and mounts. Limit straps also aid in keeping the coil springs seated inside the coil buckets.
3. Front Axle Forward/Aft Mounting Position
A. Why it matters: Moving the axle too far forward crowds the steering linkage between the axle and the steering gear.B. What to watch out for: Over-extending front control arms to push the front axle forward usually only gains a very small amount of tire clearance and can cause more harm than good if it causes steering linkages to collide, hang up, or scissor across the drag link and track bars. If you must have more tire clearance, perform some bodywork or relocate the steering gear and track-bar frame mount forward.
4. Front Axle Left/Right Mounting Position
A. Why it matters: As the axle moves up and down, the track bar also moves the axle left and right (driver and passenger).
B. What to watch out for: The track bar pulls the axle to the driver side (left) when the axle drops; it pushes it to the passenger side when the suspension compresses. Most TJs have more usable downtravel than usable uptravel due to tire and body interference. As a result, the axle will always move much quicker and farther to the driver side during suspension movement. It is often better to let the axle be slightly off center to the passenger side at ride height to compensate for this. Usually 1/2 to 3/4 inch is plenty.
1. The tie rod and drag link must never intersect or scissor across one another or the track bar.
2. Steering rod clamps and jam nuts must not hang up or catch on springs, brackets, or chassis parts. Clamps can usually be rotated and tightened to avoid a problem. Think about the effect of suspension and steering movements.
3. The tie-rod ends must be threaded into sleeves or rods at least slightly larger than the diameter of the threaded shank (e.g. a 7/8-inch-diameter shank should be threaded into a sleeve at least 1 inch or more).
4. The rod-end ball sockets should be firm, not loose. They must be greased immediately upon installation and pumped with fresh grease as needed.
5. Never allow the rod-end ball sockets to reach their limit of swivel under any suspension and steering position. Not all rod ends have the same limits of swivel, and some move more in one direction than another. Extreme downtravel positions are the most likely cause of swivel limitations. Whenever possible, remove the dust boot before articulation tests. Make sure the bodies of the rod ends will not interfere with the surfaces around the mounting holes.
6. The tapered shanks on automotive rod ends are not all the same; they vary extensively in both size and degree of taper. Test-fit the tapered shanks of the rod ends in their respective holes. It's best to remove the dust boot before test-fitting. The rod ends should seat firmly in the taper without rocking, and the holes for the cotter pins should just engage the cuts in the castle nut.
7. Inspect the steering frequently. Look for wear marks, cracks, and signs of interference. Carry some spare rod ends and hardware.
An Important Word About Hydraulic Assist Systems
Most add-on hydraulic assist (ram type) systems have been designed independently from the steering linkage and steering arm components. If the hydraulic ram continues to push on the linkage after the knuckle stops or the steering gear stops have been reached, significant damage can result if the hydraulic ram has too much power. Carefully evaluate the pump pressure, ram piston diameters, ram travel, and steering stops to make sure your steering is not being constantly overstressed each time you turn hard left or right. Remember, it's a vehicle steering mechanism, not a log splitter or tire dismounting device. Reduce pressure and find a ram cylinder with the appropriate travel that runs out at the same time or just before the steering linkage and knuckle stops.
Dynatrac offers its High Clearance steering package which has been rigorously engineered to fulfill all the key requirements for an effective TJ steering package. The kit is built to provide increased ground clearance and incredible strength, and it maximizes the full travel of the steering gear while minimizing bumpsteer and eliminating linkage scissoring and collision.
The system includes a tie rod and a drag link constructed from 1.25x0.313-inch DOM tubing, extremely tough sway-bar and track-bar mounting brackets, and a fully adjustable track bar. The kit also uses readily available replacement rod ends and the stock pitman arm.