Putting a trac bar on rear axle in MJ

Hi guys. When I haul firewood or other heavy stuff in my MJ the thing sways all over the road. It has all new bushings, tie rods, everything in the front end. Going down the highway, I notice when I start to turn the rear end wants to swing out to the side. I was wondering if putting a trac-bar on the rear axle would solve this problem. It is only present when I am hauling stuff. When empty it drives fine. So What do you all think? Am I way wrong? SHould I get new springs and shocks for the rear first or will a home brew trac bar do?


Regards,

SimpleXJ

might try an overload spring - sounds like your springs are mushy...

This is common with leaf springs. The stiffness of the bushings has a lot to do with controlling the side to side movement. It sounds like you may be overloading the MJ a bit. Wood is pretty heavy and I think the rated capacity on that vehicle is probably lower than you think.

Does anybody know the rated bed capacity on an MJ?

Use poly bushings on both ends of the spring and in the shackles and it'll tighten it up quite a bit.

Thanks for the input guys. So you think its the bushings in the leaf springs? I have a spare set sitting in my box, but I don't want to spend the time in pulling appart the old rusty SUA setup for a marginal fix. Do you guys really think this will fix it or will a trac bar do a better job?

I know I am overloading the truck a bit, but its a short drive and I don't go over 45 mph. Beats making a second trip for a few logs. Anyway, if I replace the leaf spring bushings, which I know I should, would it fix the problem or would it just lessen it when the MJ is overloaded? I also haul my ATV in the MJ sometimes and it would be great if it was more stable during those trips as well.

Thanks again

SimpleXJ

I think you're on the right track (no pun intended) thinking about a track bar. The YJ Wrangler uses a track bar with leaf springs, and back when I was a wee sprout of a lad the Hudson sedans all came with a rear Panhard Rod (which is a fawncy name for a track bar).

The trick will be that you'll want the two ends to be as close to the same height as possible so the bar runs horizontal. Otherwise, deflection will push the axle sideways relative to the chassis. If you have any way to check out a stock YJ, look under that for ideas.

Thanks Eagle. A buddy of mine has a ZJ, and while it has coils in the rear it does have a trac bar, so I'll take a peek at the concept.

SimpleXJ

New bushings would be a great help but I'd also suggest doing what I did. I added another main leaf (with the eyes cut off) to the leaf pack below the main leaf. Taking apart the leaf pack would also confirm if all your leafs were still intact. I found one broken or cracked leaf in each of my packs AND in the two packs I got from the junkyard to replace them. Fortunately I was able to make two complete sets form the good stuff. Adding the extra main leaf not only gives a higher overall spring rate, it help support the main leaf, which is woefully undersized if you're overloading the truck.
Jeep on!
--Pete

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