Prepping A ZJ’s Suspension For The Trail
The Jeep Grand Cherokee ZJ was offered from 1993 to 1998 and can be credited in great part for bringing luxury to the mass-market, midsize SUV segment. In contrast to the then-popular Cherokee XJ, the ZJ tended to impress older buyers with more citified tastes, and first-time owners of Grand Cherokees were often those who rarely ventured off the beaten path and who regularly visited their dealership for maintenance. The result is an abundance of well-maintained Grands for the present-day pre-owned market.
No vehicle is without drawbacks, however, and in the case of the ZJ, its unibody construction, while improving on-road ride and handling, inhibits suspension travel, axle articulation and chassis flex over the older-style body-on-frame architecture. Fortunately, the aftermarket has responded in recent years with a greater number of options to improve the Grand Cherokee’s off-road capabilities, including suspension kits that allow for greater amounts of suspension travel and axle movement while freeing up more room in the fenderwells for larger-than-stock tires.
Recently, we borrowed a friend’s ’95 model to evaluate a Super-Ride ZJ suspension system from Rubicon Express. Check out the highlights of the installation process (we will spare you all the common steps and just show off the more important aspects of the kit). Our good friends at Overkill Jeep Fabrication in Campbell, California, performed this installation for us.
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After our initial test drive, we contacted Rubicon Express to order a pair of adjustable upper control arms for the rear suspension because we felt the rear-axle pinion angle needed some adjustment to help eliminate driveline vibration. Otherwise, the kit performed flawlessly for us on the street and trail. Once the new rear upper arms were installed, the rear driveline vibrations were diminished significantly, and considering the fact that the owner of this vehicle plans to swap out his NV249 transfer case for a different unit—one with a fixed rear yoke arrangement—he can live with the slight vibration for the short term. However, if you plan to perform such a suspension upgrade on your ZJ, we recommend installing a slip-yoke eliminator (which Rubicon Express offers) and aftermarket rear driveline with a CV joint—especially if you plan to drive the vehicle at highway speeds. Above all, we appreciate the fact that virtually 100 percent of all Rubicon Express products are manufactured in the U.S. and come with a limited lifetime warranty against defects.
Shown here is the optional adjustable front track bar Rubicon Express offers to complement the system. While not critical to the system’s functionality, this upgrade allows the front axle to articulate more freely than the stock arrangement does. It features a replaceable rod end at the chassis end, and a durable polyurethane bushing at the lower (axle) end.
To install the RE adjustable track bar, a hole in the factory upper track bar mounting bracket had to be enlarged to 5⁄8 inch. This would allow clearance for the larger 5⁄8-inch mounting bolt.
We went ahead and had the guys at Overkill Jeep Fabrication double-plate the lower mounting bracket on the axle to ensure strength. The RE instructions didn’t require this, but we felt it was a good idea. Here you can see the bracket prepped for the welding process.
This is how the new lower mount looked after it was double-plated. Addressing little touches like this is why we like working with the professional crew at Overkill Jeep Fabrication.
This is how the upper track bar mount looked after the unit was installed. While we don’t typically mount a track bar end in a single-shear arrangement as shown here, Rubicon Express assured us that with regular routine inspection this mounting method works flawlessly.
6. To finalize the installation, technician Scott Tashiro put the vehicle on the ground and hooked up and adjusted the front and rear track bars. Next, he set the front axle pinion angle by adjusting the front lower control arms. Once these steps were completed, a front-end toe adjustment was made and the new suspension system was double-checked to ensure that proper torque specifications were met.