FJ40 traction bar design/install instructions.....
performed June 2000
I actually did this project twice...the first time I made the mistake of using thinner pipe and mis-designing where the torque would be on the bar itself. I relied to heavily on the upper link and expected the lower link to take less strain...big mistake!
The photos pretty much explain themselves. You need some 1" OD 3/16" wall DOM tubing (about 6 feet), one 5/8" heim joint, 3 used shock eyes and associated 5/8" ID poly bushings, some 3" x 1/4" steel (about 16-20" total), and finally one used stock FJ40 shackle. Total cost for the project should run you about $60-$75 dollars.
First, cut the 3" steel in half and begin the laborious process of getting both halves to fit the axle tube. This was the biggest hassle. You want the traction bar as centered as possible, but perfect is not necessary. Offset will work equally well too, if you want to make the fitting process easier. I fit the bracket, welded the upper brace in place (see photo), and then refit it a few times. I then drilled the 5/8 holes using a drill press. You want to locate the lower mounting hole almost level with the lower tube on the axle for max clearance. Once you're happy with the fit and alignment horizontal and verticle, you can tack the bracket into place. Don't weld fully until the balance is designed.
Your next step is to figure out the length for the upper and lower bars...this will vary with most applications...my axle is further back due to reversed rear springs and other folks have removed their factory crossmember. Take your measurements, double check, and take your time. Once you've got your length's estimated and the upper and lower bars cut, weld on the two shock eyes for the axle mount. Fit these into the mount to determine the angle cut for the opposing end and the length of the verticle brace. Cut as necessary and tack into place while under the vehicle....there's no room for errors, since redoing is a pain! (TRUST me!!)
Finish welding the bar into one piece. To attach the heim at the end, drill out a 5/8 hole and thread the nut all the way up the heim. Slip the heim into the hole and tack on the nut. Remove the heim and finish welding the nut into place.
Now drill out your shackle to the 5/8 hole size and bolt it up!!
I (and others) have noticed that the upper axle-side shock eye gets egged-shaped from the load placed on it. I cut that eye off, welded on a 5/8-fine nut, and used a 5/8-5/8" heim joint at that point. Seemed to tighten things up a bit, and should be a stronger solution. Another option would be to "wrap" the shock eye with additional metal to add strength. I experienced no problems with the lower axle-side mount or with the cross-tube mount.