Installing a Shackle Reversal Kit on a Jeep Wrangler
By: Randy L. Wheeler - 3/2001
Installing a Shackle Reversal Kit on a Jeep Wrangler
|The Shackle Reversal Kit from Full Traction Suspension
(click on each component for full size image).
A shackle reversal basically swaps the position of the pivoting shackle on the front of the spring to the rear and the fixed mount in the rear is moved to the front. This "reverses" the shackles. Installing a shackle reversal kit does a number of things. By reversing the shackles, the ride quality is smoothed out and that dreaded "bump steer" associated with lifted rigs can be significantly reduced.
The smoother ride is attributed to the available movement of the spring and axle when it compresses over a bump. In a stock configuration, when the tires encounter a bump, the force tends to want to push the tire forward since the shackle rotates that way. With the shackle reversal configuration, when you hit a bump, the spring gets pushed up and back and the as the spring compresses, it travels towards the rear, thus resulting in a smoother ride. Additionally, since the springs now travel rearwards when you encounter a bump, the camber is increased and that results in more stable steering.
The shackle reversal kit from Full Traction Suspension (FTS) is a new product designed specifically as a bolt on application. No welding is required! This is a big plus for us shadetree mechanics who either don't know how to weld or don't have access to a welder. This means you can easily install this kit in an afternoon. The basic components of the kit include two front spring towers, a main cross bar, two replacement rear shackles and all the mounting hardware. The front spring towers are made out of 1/4-inch steel plates that are machine bent and welded for exceptional strength and long life. The main support bar is rectangular tubing and is welded onto the end brackets. The rear spring shackles are also made from 1/4-inch steel and welded onto the cross tubes.
|Remove the front bumper and shackles.|
|Remove the front spring hanger bushing and replace it with the supplied metal bushing.|
|Install the spring towers onto the frame and secure it with the supplied bolts. Install the main cross bar at this time.|
|View showing the rear mounting bolt. This bolt mounts through the backside of the spring tower and through the spring hanger. There is already a hole there, so no drilling is required.|
Installation of the shackle reversal kit can easily be done in an afternoon using simple hand tools. To start, jack up the front of the rig and support the jeep using jack stands placed on the frame rails behind the rear spring hangers. Remove the front bumper and disconnect the front drive shaft at the axle. It would also be a good idea to remove the front shocks at this time so that the springs can droop as much as possible.
With the front bumper removed, it's time to start removing the front shackles. Work on one side at a time so you can manipulate the axle around to remove the weight from the springs. Place a floor jack beneath the spring and slowly raise it up until most of the weight is off the leaf spring then remove the shackle.
The shackle reversal kit comes complete with new steel bushings that replace the rubber bushings on the front spring hanger. Pull the rubber bushing off using a pair of pliers or vice grips and insert the supplied metal bushings. Be sure to add a bit of grease to the bushings before installation. Now would be a good time to inspect the frame rails for any cracks or broken nuts. In my case, I noticed one of the welded nuts on the inside front of the frame was broken off. I didn't have a welder to tack weld another nut on so I opted to use a standard Grade 8 nut and bolt instead.
Once the steel bushings are in place (remember to install them into both sides of the spring hanger), you can test fit the front spring tower. The spring towers fit over the spring hanger and tuck up right against the bottom of the frame rail. The front spring tower is secured to the frame using three bolts: 1) a main bolt through the spring hanger bushing, 2) a bolt through the underside of the frame rail, and 3) a bolt through the rear of the tower and through the backside of the spring hanger. These things aren't going anywhere! Getting the nut and lock washer into the tight space between the spring tower and the backside of the spring hanger was pretty interesting. There isn't a whole lot of room to work with in there.
Since one of the welded nuts was missing from the frame rail, I used a Grade 8 bolt, washer and nut to secure the front of the spring tower. This is the same hole that most stock bumpers get mounted with from the underside of the bumper. If you are using a bumper that uses this lower mounting hole to secure the bumper, you'd want to re-weld a nut on the frame rail, otherwise, once you installed the bumper, there would be no way to get a wrench inside to tighten up a non-welded nut. This would be the time to remount your bumper and sandwich the bottom of the bumper between the top of the spring tower and the bottom of the frame rail then insert the bolt through the spring tower, the bumper and into the welded nut on the frame rail.
Secure each bolt and torque to the recommended specifications. Once the spring towers have been installed and all the backside and front bolts torqued down, install the main cross bar between the spring towers.
Position the cross bar into place and install the upper bolt through the spring tower and through the cross bar bracket. Repeat this on the other side so that only the top two bolts are through the cross bar brackets. This will let you swing the cross bar into place when installing the lower bolts for the spring eyes.
Using the floor jack beneath the spring, slowly raise the spring until the eye is level with the lower mounting holes of the spring tower. Install the supplied bolt through the hole and through the cross bar bracket. Do not tighten. Install the lower bolt on the other spring tower and secure the bolts with the supplied washers and nylock nuts. Torque the bolts to the recommended specifications. The front is now completed. Now we can move to the rear spring shackles.
In the stock configuration, the leaf spring is secured to a spring perch that is welded onto the frame rail. With the FTS kit, we simply remove the spring from the perch, insert the supplied shackle into the perch and bolt the spring to the new shackle. What could be easier?
To install the rear shackles, remove the rear shackle bolts and lower the springs until they drop out of the hangers. Install the supplied shackles, making sure to grease the bushings before inserting them into the spring hangers. Jack up the spring until the eye is level with the shackle and insert the supplied bolt through the shackle and spring eye. Repeat this on the other side. The rear is now completed.
Recheck all bolts for tightness, install the shocks and drive shaft, lower the vehicle onto the ground and you're finished with the installation. Well almost. After reconnecting the front shocks, I realized that they were almost completely extended. A quick measurement confirmed that my Rancho RS9000s (9168's) had only about 1/4-inch of travel left! Longer shocks are definitely required. The best way to measure for new shocks would be to disconnect the front shocks and put your rig up on a ramp. With the rig on the ramp, measure the compressed and extended lengths between the upper and lower mounting points for the shocks. Also measure the distance between your bump stop and the axle (or if your bump stop is mounted ON the axle, measure from the bump stop to the frame). With the compressed, extended and bump stop measurements in hand, you can order the proper length shock for your application. You may also need to install longer bump stops to prevent the shock from topping out under full compression. While your rig us up on the ramp, also check to make sure your brake lines are not over stretched. If so, extended brake lines may be required. Since I had already gone to longer brake lines up front, I didn't have to change out the brake lines.
Since the shackle reversal kit moves the front axle forward by about 1-inch, it also extends the front drive shaft. In my case, the front drive shaft was extended by about an inch. To prevent the spline section of the drive shaft from pulling out during extreme articulation, a new driveshaft is required to correct this problem. Many companies, such as Tom Wood's Custom Drive Shafts and South Bay Drivelines, make long travel drive shafts that are perfect for this type of application.
This shackle reversal kit from Full Traction Suspension is truly a bolt on application. Before I installed the kit, I took some height measurements and compared them with the post installation height. This kit provided an extra 2 1/4-inches of lift! The kit also comes with a set of boomerang style rear shackles (for the rear leaf springs). These shackles provide the necessary lift in the rear to raise the back end up level with the front.
On road driving is much smoother and the jarring affect of bumps through the steering wheel has been reduced significantly. Longer shocks and a longer travel front drive shaft will complete the installation. I'm looking forward to getting back on the trail to see how this kit performs off road.
|View showing the rear shackle installed.||Another view showing the rear shackle. Notice the extension of the front drive shaft. A longer drive shaft is in order.||The completed installation. I'm working on getting a custom front bumper made up to complete the front end. For now, my stock bumper will have to do.|