|ISUZU-Torsion Bar Upgrade on '92-'01 Troopers|
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.
|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
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).
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
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
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.
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
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.
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 firstname.lastname@example.org for this detailed article!|
|Last updated on 10/23/2001 06:23 PM|