ISUZU-Torsion Bar Upgrade on '92-'01 Troopers

General Info:
Many Trooper owners have upgraded their rear coil springs, with stiffer and/or taller coils from Old Man Emu (OME), CALMINI, and the like, but relatively few of us have upgraded the spring rate (stiffness) of the front suspension. I have been curious if the stiffer torsion bars available from Sway-A-Way or CALMINI would make a good match for the OME rear coils and shocks already on my Trooper.

First, a word about torsion bars. A torsion “bar” is actually a spring that performs the same function (for the front suspension) that the coil springs do for the rear. Instead of compressing a coil, the torsion bar twists (or “torques”, hence the name “torsion bar”).

Also, some context on my Trooper: I bought my 1999 Trooper in November of 1999. In June of 2000 I firmed up the notoriously soft ride of the Trooper with OME Nitrocharger shocks. About six months later I added the OME rear coils. This lifted the rear of the vehicle about 1.5 inches, give or take. To level out the ride, I cranked up the stock torsion bars a corresponding amount. Shortly thereafter, I put on LT265/75R16 Pirelli Scorpion AT tires, which are about 2” bigger diameter than the stock tires.

So to summarize, prior to this torsion bar upgrade I had previously upgraded the shocks, tires, and rear coil springs. All of these upgrades had increased the ride height by two to three inches, and although the OME shocks had significantly reduced nose dive and body roll, the increase in ride height took back some of my gains in body roll. I hoped the stiffer torsion bars would further reduce the body roll on cloverleafs and cornering.
Meat and Potatoes of the Install:

And now, on to the install. I ordered Sway-A-Way Part No. 1549. These torsion bars are substantially thicker than stock. The stock bars are roughly 26 millimeters (mm) in diameter, while the Sway-A-Ways (SAWs) are roughly 29 mm. According to SAW, their torsion bars will offer a 20 – 30 percent stiffer spring rate than stock.

The torsion bars are straight, round bars with splines at each end, roughly four feet long. They are painted white, displaying a “Powerbarz” sticker. They come from the factory stamped “L” or “R”. Check to make sure you have one of each; though they look alike they are not interchangeable.

1.      Jack up one side of your vehicle until the front wheel is off the ground, and place a jackstand under the frame. Don’t support the vehicle by any part of the front suspension, your goal is to unload the suspension as much as possible. Refer to your owner’s manual for safe jacking procedures. I recommend safety glasses as well, mostly to protect your eyes from the grit that will inevitably fall off the vehicle while you are working under it.

2.      Grab a half-inch socket wrench or breaker bar and a 27-mm socket, and get under side of the vehicle, midway between the tires. Locate the torsion bar adjustment bolt (these are my terms, not necessarily the same terms the instructions use). It is easy to see, just inside the frame rail, roughly in line with the B pillar (the B pillar is between the two side doors).

3.      Remove the bolt, counting the number of turns until tension is entirely relieved on the bolt. I counted about 20 turns on mine, but remember I had already cranked the torsion bars up for the OME lift. The newer the vehicle, the easier this bolt will be to turn. Due to inevitable corrosion, older vehicles may require the use of a long breaker bar and/or penetrating oil. After the tension is off, continue removing the bolt until it comes out, along with two large half-moon shaped nuts.

4.      Now comes the part that wasn’t in the instructions (which were very generic). Get a 17-mm socket and loosen (but do not remove) the nuts on the lower control arm bracket at the other (front) end of the torsion bar. This will allow the bar to pivot slightly and take the remaining lateral tension off the bar. Without doing this, the tension will make it difficult if not impossible to remove the bar from the bracket, due to binding of the splines. The nuts are very tight, so a breaker bar is helpful to break them loose.

5.      Now you should be able to lift the rearward end of the torsion bar enough to pull off the tensioning arm. It isn’t held on by anything but friction at this point.

6.      Draw the entire torsion bar to the rear, to pull it out of the front bracket, and remove it from the vehicle.

7.      Get the replacement SAW torsion bar, checking to make sure you have the correct one for the side you are working on: “L” for drivers side, “R” for passenger side. I pointed the stamped end to the rear, same as the factory bars were. Leave the protective caps on the splines for the moment. Insert the bar carefully above the frame rails, into rough position. The instructions advise against nicking or scratching the bars, although superficial scratches in the paint shouldn’t affect function at all.

8.      Remove the protective caps. Grease the splines on the frontward end of the torsion bar. Save the caps for storing the stock torsion bars – never know when you’ll need ‘em!

9.      Push a screwdriver or similar implement under the front bracket on the lower control arm, just to keep the bracket vertical. Insert the torsion bar into the bracket. It will go in easily once the splines are lined up. Remove the screwdriver.

10.  Grease the splines on the rearward end of the torsion bar. Hold the end of the bar up off of the frame crossmember, and slide the tensioning arm onto the splines. Line up the tensioning arm so it will fit into the U-shape channel of the crossmember, and set the torsion bar/tensioning arm assembly down on the crossmember.

11.  Tighten the nuts on the front bracket on the lower control arm.

12.  Grease the curved surfaces of the half-moon tensioning arm nuts. Reinstall the tensioning arm bolt and half-moon nuts. Once you feel some tension on the bolt, start counting the turns. Crank about two-thirds as many turns as it took to remove the old torsion bars. Because the new bars are stiffer, you won’t need as many turns to achieve the same ride height. You’re done with this side!

13.  Repeat Steps 1 through 12 for the other side.

14.  Go for a drive around the block to settle in the torsion bars and adjustments.

15.  Check your ride height, front to rear and side to side. I just do this by eye, because you can drive yourself nuts trying to measure the height precisely. Exact ride height will vary due to a variety of factors, including vehicle load (even how much gas is in your tank), slope of the ground you are measuring on, basic slop in the suspension, temperature of the shocks, etc.

16.  Adjust final front ride height via the torsion bar adjustment bolt (see Step 2). One full turn equals roughly one-quarter inch change. Looking down on the bolt, turn clockwise to raise the front corner of the vehicle, counterclockwise to lower. This is easier to do when the vehicle is jacked up, but I was able to adjust mine without jacking.

In Summary:

That’s it! This project is no more difficult than changing shocks, maybe easier. Now that I have done it once, I am sure I could do it again in one-third the time – but hey, what project isn’t like that?

So how does it ride with the new SAW torsion bars? It’s really too soon to tell, as I have only had them on a few days, but initial impressions are favorable. The ride is firmer, though not oppressively so. The nicest thing is the reduction in body roll. I don’t feel the need to grab the handle between the seats going around a cloverleaf! Springs often will mellow a bit after install, so we’ll see how they do in the days to come.

Thanks to Steve Carlson for this detailed article!
Last updated on 10/23/2001 06:23 PM