We've watched as the new Jeep JL Wrangler continues to conquer just about everything in sight. At the same time, the off-road aftermarket has been responding to Jeep's new Wrangler by cranking out hundreds of new parts and accessories to upgrade and outfit one of the newest stars in the Jeep universe. We've been especially keen on all the new suspension and handling products for the Jeep Wrangler JL that have become available over the last year or so. Skyjacker jumped into that arena early on and has continued to refine its JL suspension system offerings, including one of its newest kits that's specially designed for the Jeep Wrangler JL Unlimited Rubicon—Skyjacker's (skyjacker.com) 3.5-4-inch Suspension Lift Dual Rate Long Travel Lift Kit System with Skyjacker Black MAX shocks.
In this kit (PN JL40RBPBLT) you get dual-rate coils springs for front and rear, front and rear extended antisway bar endlinks, front and rear bump stop extensions, front adjustable track bar, rear track bar drop bracket, and four Skyjacker Black MAX shock absorbers. All the necessary replacement hardware is included, but much of the factory hardware is retained and reused. The kit also included front and rear eccentric cam-D bolts for rotating the axles to adjust pinion angle, which we didn't need because we paired the suspension lift system with Skyjacker's Wrangler JL (2-4-inch) Single Flex Front and Rear Lower Link Set (PN JL24LLX). The new lower links are hugely strong in comparison to the factory lower links and feature a single adjustable rod end (to the frame) that allowed us to make any needed pinion angle adjustments.
Exchanging the capable stock suspension system (front passenger corner pictured) of this Jeep Wrangler JL Unlimited Rubicon for the even more capable Skyjacker 3.5-4-inch Suspension Lift Dual Rate Long Travel Lift Kit System with Skyjacker Black MAX shocks and Skyjacker 2-4-inch Single Flex Lower Links gave our rig a whole new set of powerful legs with which to climb over obstacles.
The Skyjacker Dual Rate Long Travel coils feature a tightly wound upper top half with a lighter spring rate that works to create a smooth and controlled highway ride, while the more loosely wound lower half has a higher spring rate that engages during heavy off-road suspension movement for consistent control and stability. The coils are designed to allow for maximum suspension droop to keep the tires on the ground but keep the coils from being pulled from their upper coil buckets. The factory coils have a linear design that maintains the same rate throughout most of the suspension travel.
Packed inside a Skyjacker Black MAX shock is a foam cell insert that compresses when the shock gets hot from working hard, compensating for oil expansion and maintaining consistent damping performance throughout a broad operating temperature range. This helps with increased heat dissipation and fade reduction, and it eliminates air inside the shocks so they can be mounted in any direction. The pistons are sintered iron, end mounts are 360-degree welded, and it's packed with heavy-duty control discs. The shock valving is custom-tuned to match the specific vehicle application, so you're not getting a one-size-fits-all product.
A few important details: The drag link must be adjusted to center the steering before the vehicle is driven. Failure to do so will cause computer errors, odd handling characteristics, and poor performance. If tires larger than 10 percent greater than factory are installed, speedometer recalibration will be necessary. After installation, a professional alignment is required to align the vehicle to factory specifications.
We were not shocked at how well all the parts and pieces fit and worked together, but we were surprised by how easy the installation really was. The entire job—from zipping off the factory wheels and getting at the suspension, all the way to dropping it back down on the ground with new rims and rubber ready for final alignment before being truly roadworthy—took around 5 hours. Of course, we had the assistance of a hydraulic lift, a shop full of air tools (courtesy of 4 Wheel Parts, 4wp.com), and a top-flight technician, so that did give us a bit of an advantage. And we read the instructions ahead of time to fully understand the procedure and exactly what was necessary. With appropriate home-garage safety (extra floor jacks and jack stands) and all the right tools at your fingertips, you and a buddy could have it done before dinner. Here's how we did it and some things we learned along the way.
You could do this installation in your home garage. It's not difficult, but you will need some way to raise and lower the axles in relation to the frame. Without a lift, which we were lucky enough to have access to for this job, you'll have to jack up the frame onto jack stands and lower the axles with a floor jack to separate the two enough until it's possible to remove the factory springs and install the Skyjacker springs.
With the bottom of the front shock loosened from its perch on the axle, antisway bar links removed, track bar loosened, and brake lines free from their clips, each side of the front axle was in turn lowered enough to remove the factory coil springs.
With coil springs removed from both sides of the front axle and the axle lifted back up enough to temporarily reconnect the factory shocks (to help secure the axle), the front lower axle link arm was removed from each side.
As you can see in this photograph, there are radical differences in the lower axle link (front shown) and the Skyjacker 2-4-inch Single Flex Lower Link. These are to be installed one side at a time, with the offset bend in the front lower control arms toward the inside of the Jeep.
Measure the distance between the bushing centers at the ends of the new Skyjacker control arms. Rotate the adjustable rod end, while keeping the ends square with each other, until the Skyjacker front lower control arms measure 24 inches from center to center and the Skyjacker rear lower control arms measure 19 15/16 inches from center to center. Tighten the jam nuts.
Using the OEM control arm hardware that we saved, the new Skyjacker front lower control arms were installed, making sure to place the adjustable rod ends at the frame.
Side by side for comparison, the differences between the Skyjacker two-stage front spring replacement (above) and the factory front spring (below) become obvious. Skyjacker's tightly wound upper half with a lighter spring rate is combined with a more loosely wound lower half with a higher spring rate. The factory spring has a linear rate throughout the coil and can't deliver the broad performance characteristics of the Skyjacker Dual Rate Long Travel.
Jp Pro Tip: Because you must have the new Skyjacker lower bumpstop inside the new Skyjacker coil when the coil is installed, we used a zip tie to temporarily keep it secured during the process of placing the new coil in its proper position. Be sure the tabs of the OEM front upper coil spring isolators (which you saved to reuse here) are aligned with the holes of the OEM front upper coil spring mounts.
Once the Skyjacker front coil springs are correctly aligned and installed into the front upper mounts and on the front lower coil pads, the zip ties holding the lower front bumpstops can be cut, the bumpstops dropped down through the spring, and then affixed to its perch. We used a swivel between the socket and the 7/32-inch hex for this job.
Now that the new front coils and lower front control arms are installed, the front axle can be lifted one side at a time to compress the springs enough to reconnect systems like the brake lines (using Skyjacker's new front brake line brackets), the electric plug for the 4WD actuator, and the axle vent hose. This is also the time to install the new shocks—in our case, Skyjacker Black MAX shocks.
New front Skyjacker Black MAX shocks were installed using the kit-supplied steel sleeves and polyurethane bushings. Factory mounting hardware is reused for the front shocks. The top front (pictured) uses the larger inside diameter bushings with the longer steel sleeves; the smaller inside diameter bushings and shorter steel sleeves fit the bottom front shock mounts. Kit-supplied dust boots had been fitted prior to installation and were zip-tied securely into place before final tightening of the mounting hardware.
Factory antisway bar endlinks were tossed in favor of longer and stronger Skyjacker endlinks. Kit-supplied replacement bushings and steel sleeves, along with factory endlink mounting hardware, were used for their installation.
With the new Skyjacker front suspension system all stickered up and ready for action, we moved on to the rear end of this 2019 Jeep JL Unlimited Rubicon.
We've jumped ahead a few steps here, but with the factory rear track bar loosened, rear brake line brackets disconnected from the frame and axle, and rear shocks and coils removed in the same manner in which we dispatched the front shocks and coils, the factory rear lower control arms were then replaced with the new Skyjacker lower control arms (note the adjustable rod end is mounted at the frame). The Skyjacker replacement lower control arms are not only adjustable using the rod end on their upper mount ends—they are also physically larger and much stronger.
Installation of the new Skyjacker rear upper track bar bracket to the frame is performed as shown in this photo, with the double-hole side of the new rear upper track bar bracket toward the outside of the frame using the kit-supplied hardware. The 1/2x9/16-inch bolts should be installed with their threads inward of the new rear upper track bar bracket. We found it necessary to grind a tiny bit of material off the welds where the factory rear upper track bar bracket was attached to the frame so the new Skyjacker bracket could be easily slid into place over the factory bracket for installation. The other end of the track bar was left loose at this point.
We found that just about everything attached to the rear axle (including the parking brake cables) had to be removed from its mounts in order to lower the rear axle far enough away from the frame to make installation of the new Skyjacker rear coil springs easier. The new rear Skyjacker coils are unique to their sides; the new rear coil with an "L" as the last digit in its part number is for the left (or driver) side of the rear axle, and the new rear coil with the last digit "R" in its part number is for the right (or passenger) side of the rear axle.
With the coil springs securely in place now, the next step was installation of the new Skyjacker rear bumpstop spacers to the factory rear bumpstop pads using the kit-supplied hardware. The new bumpstop spacers should be placed so the angled end is toward the rear of the vehicle.
The new Skyjacker rear Black MAX shocks were easily installed once the rear axle was jacked back up to compress the springs. This also allowed us to reattach all the hoses and cables that had been loosened to get the springs in. The rear shocks use the larger inside diameter polyurethane bushings and longer steel sleeves on their upper mounts, while the smaller inside diameter bushings and shorter steel sleeves are for the rear shock's lower mounts. The new Skyjacker antisway bar endlinks were also installed at this time.
While the Jeep was still up in the air, we went around and tightened up every nut and bolt that had been loosened, replaced, or reused during the installation of the Skyjacker 3.5-4-inch Suspension Lift system on our 2019 Jeep Wrangler JL Unlimited Rubicon.
Jp Pro Tip: Once all the suspension system hardware was tightened to proper torque specifications, we went back over all the most critical with a bright red permanent marker to create an easy visual key to their position. It's easy to check all the hardware for any loosening down the road (and trail) by looking to see if the red lines are still in proper alignment.
At this point we bolted up the new tires and wheels. The Skyjacker 3.5-4-inch Suspension Lift system allowed us to easily fit a set of huge meats like the 37x12.50R17LT Pro Comp Xtreme MT2 tires wrapped around 17-inch Fuel bronze-toned wheels.
While the rig was still up in the air, we installed the left (driver) side of the rear track bar. That way the body would center itself over the rear axle as we slowly lowered the Jeep JL to the ground.
With the Jeep back on solid ground, we used a measuring tape to be sure the body was centered over the front tires/wheels, and then we adjusted the rod end of the new kit-supplied Skyjacker front track bar (we had previously installed the non-adjustable end at the frame) to line up with the lower front track bar mount on the axle. Then, we attached it with the factory hardware saved during the removal of the factory front track bar.
The before and after is like night and day. Our subject was a 2019 Jeep Wrangler JL Unlimited Rubicon with the 3rd-gen Dana 44 heavy-duty solid front (above) and rear axles and factory-supplied, high-pressure, gas-charged monotube shock absorbers. That was all fine and dandy for a while, but eventually we wanted more, so we decided to take it up a notch (below) with Skyjacker's 3.5-4-inch Suspension Lift system with 2-4-inch Single Flex Lower Links and Black MAX shock absorbers.
Metric & Standard Wrenches and Sockets
Hex Key Sockets/Wrenches
Fastener Removal Tool
Jack Stands (two or more are preferable)