1990 Isuzu Trooper
Upgrade - Build - Test
Suspension Modifications
Front Suspension Lift
After a few trips offroading with 33" tires I was getting tired of hearing the rear tires catching the fender lip and shaving rubber off. I did limit this by installing larger rear bump stops. However this limited my suspension travel somewhat and in really harsh situations it would still catch a bit. It was time for a lift. I bought all my parts around Christmas 2010 and did the install on the weekend of Jan 22/11. The kit consisted of Old Man Emu (OME) leaf springs, extended shackles (that I built), new OME shocks, new extended stainless steel brake lines and a torsion bar crank in the front. The installation of the kit was very straight forward, there were only a few snags along the way.
When the torsion bars are cranked up in the front it causes the tires to camber positive beyond what the stock setup can accommodate. So in order to combat this you flip the upper ball joint so it mounts under the control arm and you also install a spacer. This allows you to get the truck back into alignment after the lift. The installation of the part was very simple but the manufacturers failed to radius the inner edge where it is closest to the ball joint so it hangs up on the ball joint where the body makes a radius into the mounting flange. So if you install the spacer without out grinding a matching radius into it you could cause some serious binding. Also the spacer is shipped with 1/4" bolts that should be M6 bolts. So I went to my local parts store and got 12.9 grade M6 flange head bolts. The rest of the front end was very simple. Bolt the shocks in, install new brake lines and put the wheels back on.
Rear Suspension Lift
When the rear leaf springs went in the shackle side was good since I made them myself. The front however was a little more difficult. There is a sleeve that goes in the center of the front bushings. OME does not give you a new one and my stock one would not work. It may have been because it was damaged from age making it larger than it originally was or because it was too big from factory to fit the OME bushings. Luckily my friend owns a machine shop and was working on a Saturday, he was able to machine me new ones. Another solution would be to order Energy Suspension bushings instead because they include a new sleeve. The rear shocks presented the same problem. The lower bushing that attaches the shock to the spring plate was very sloppy so again my friend who was now working on a Sunday saved the day by machining sleeves for the shocks. After those minor problems were solved the rest was easy.
Once all the tires were back on and the truck was back on the ground it was time to set the ride height in the front. The weight was taken off the front tires and I marked the torsion bar bolts so I could count the turns. I started with 4 turns which equaled about 1 inch of lift then lifted it back up and added another 6 turns. The front was now about 1 inch lower than the back but I expect the back to come down after everything settles in so I will adjust the front about 1/2 to 3/4 inches lower than the front so that when I load the back the truck wont squat in the rear.
Fabricated Shackles
Here are the shackles I made. They are made from 3/8" x 1 1/2" stock with a 3/8" plate welded in the center for stiffness. The bolts are 12.9 grade M18 bolts drilled with a grease channel. They are also selected with a 3 1/2" shank so the bushings do not ride on any threads. They are machined to length. I also welded tabs on the side where the bolt head is so that they cannot turn and only require one wrench to tighten and loosen the nut.