There is a moment every Jeep Wrangler owner knows: you are crawling over a rock ledge, and you hear that sickening crunch of your skid plate meeting the earth. Or perhaps you have simply grown tired of the factory stance, which leaves your 35-inch tires looking like they belong on a toy. The solution is a lift kit, and for many, the gold standard is the Mopar 4-inch lift. This factory-engineered system promises to maintain your warranty, preserve ride quality, and give your Wrangler the aggressive posture it deserves.
In this comprehensive guide, we will walk you through the entire installation process for the Mopar 4-inch lift kit on a Jeep Wrangler JL or JK. Whether you are a seasoned weekend mechanic or a first-time lifter, this article will cover the tools required, the critical steps for a safe install, and the post-installation adjustments that make the difference between a good lift and a great one. By the end, you will have the confidence to tackle this project and the knowledge to avoid common pitfalls.
Understanding the Mopar 4 Lift Kit: What You Get in the Box
The Mopar -inch lift kit is unique because it is designed and tested by the same engineers who built your Wrangler. Unlike aftermarket kits that require cutting, welding, or extensive modification, the Mopar kit is a bolt-on system that integrates seamlessly with your vehicle’s existing geometry. The kit typically includes front and rear coil springs, Fox shock absorbers, front and rear sway bar links, a front track bar relocation bracket, and all necessary hardware. For JL models, you also get a new front lower control arm to correct caster angle.
One of the most important components in this kit is the Fox shocks. These are not generic replacements; they are specifically tuned for the Mopar lift, offering a balance between off-road articulation and on-road comfort. The are progressive rate, meaning they stiffen under heavy load but remain compliant during normal driving. This is critical because a 4-inch lift changes the vehicle’s center of gravity, and wrong spring rate can make the ride harsh or unstable.
Before you begin, you must verify that your Wrangler is compatible. The Mopar 4-inch lift is for two-door and four-door models, but it does not fit the 392 or 4xe variants without additional modifications. You should also check your tire size; this kit is optimized for 35-inch tires, though many owners successfully run 37s with minor trimming. Open the box, lay out all the parts, and compare them to the included instruction sheet. Missing hardware is rare, but it is better to discover it before you have your Jeep on jack stands.
Tools, Safety, and Preparation: Setting Up for Success
successful lift installation starts with the right tools and a safe workspace. You will need a floor jack with a minimum 3-ton capacity, four heavy-duty jack stands, and a set of wheel chocks. For the bolts, you will need metric sockets ranging from 10mm 24mm, a torque wrench capable of 150 ft-lbs, and breaker bar for stubborn fasteners. A ball joint press or pickle fork is essential for disconnecting the sway bar links, and a spring compressor is highly recommended for safety when removing the factory coils.
Safety is non-negotiable. The coil springs on a Wrangler are under significant tension, and releasing them without a compressor can cause serious injury. Always work on level ground, and never place any part of your body under the vehicle unless it is supported by jack stands, not just the jack. Wear safety glasses, as rust and debris will fall into your eyes. It is also wise to spray all bolts with penetrating oil the night before the install to break loose any corrosion.
Preparation also involves planning your time. A first-time installer should budget a full weekend for this job. You will need to remove the wheels, disconnect the brake lines and ABS sensors, and carefully lower the axles to remove the old springs. Have a friend on standby for the heavy lifting, especially when aligning the new track bar and control arms. Finally, clear your garage floor and have a clean area to organize the new parts. A messy workspace leads to lost bolts and frustration.
Step-by-Step Installation: Removing the Factory Suspension
Begin by lifting the rear of the Wrang first. Place jack stands under the frame rails, not the axle, and remove the rear wheels. Disconnect the rear sway bar links using a 15mm socket. Next, support the rear axle with the floor jack and remove the lower shock bolts. The factory shocks will slide out easily once the bolts are removed. Now, carefully lower the axle until the coil springs are loose enough to remove by hand. If they are stuck, use a pry bar gently, but never force them.
With the springs removed, you can now install the new Mopar springs. These are color-coded for left and right, so double-check the labels. Place the new spring into the upper perch, then raise the axle with the jack until the spring seats properly in the lower perch. Do not fully tighten the control arm bolts yet; you will torque them once the vehicle is on the ground. Install the new Fox shocks by reversing the removal process, and attach the new, longer sway bar links. Torque all bolts to factory specifications listed in the manual.
The front suspension follows a similar process but is more complex due to the track bar and steering components. After lifting the front and removing the wheels, disconnect the front sway bar links and the steering stabilizer. Remove the front shocks and lower the axle to extract the front springs. The Mopar kit includes a track bar relocation bracket that must be bolted to the passenger side frame rail. This bracket corrects the axle position after the lift. Install the new front springs and shocks, then attach the new lower control arms. These arms are longer than stock and will restore proper caster angle, preventing wandering on the highway.
Critical Post-Install Adjustments: Alignment, Torque, and Brake Lines
Once all four corners are assembled, the work is not done. The most critical step is bleeding the brakes and extending the brake lines. The Mopar kit includes brackets to relocate the factory brake line brackets, preventing the lines from stretching or tearing during full suspension articulation. Remove the factory bracket, install the new bracket lower on the frame, and secure the brake line. You must also check the ABS sensor wires; they should be zip-tied away from moving parts.
Next, you must perform a final torque check on every bolt. The control arms, track bar, and sway bar links should be torqued with the vehicle’s weight on the ground. This is called a “loaded torque” and ensures the bushings are not twisted, which would cause premature wear and a harsh ride. Lower the Jeep off the jack stands, rock it back and forth to settle the suspension, then torque the control arm bolts to 125 ft-lbs and the track bar bolt to 90 ft-lbs.
Finally, you must get a professional alignment. A 4-inch lift changes the toe, caster, and camber angles. While the Mopar kit corrects caster with the new control arms, the toe will be off. Driving with incorrect toe will destroy your new tires in under 500 miles. Take the Jeep to a shop that specializes in lifted vehicles and ask for a “lift alignment.” They will set the toe to zero and ensure the steering wheel is centered. This step is not optional; it is essential for safety and tire longevity.
Common Mistakes and How to Avoid Them
The most common mistake during a Mopar 4-inch lift install is failing to properly seat the coil springs. If the spring is not seated in the upper and lower perches, it can pop out during off-roading, causing catastrophic damage. Always rotate the spring so the end of the coil aligns with the stop on the perch. Another frequent error is over-tightening the sway bar links. These links have rubber bushings that need to flex; if you crush them by over-torquing, they will fail quickly. Use a torque wrench and follow the spec.
Another pitfall is neglecting the steering stabilizer. The factory stabilizer is often too short for a 4-inch lift, leading to bump steer and a loose steering wheel. The Mopar kit does not always include a new stabilizer, so you may need to purchase an aftermarket one separately. Install it after the lift is complete to ensure proper clearance. Additionally, many first-timers forget to check the driveshaft angles. On a 4-inch lift, the rear driveshaft may vibrate at highway speeds. If you feel a vibration, you may need a transfer case drop kit or a new driveshaft.
Finally, do not rush the break-in period. The new springs and shocks need about 500 miles to settle. During this time, avoid hard off-roading or heavy towing. After 500 miles, re-torque all suspension bolts and check the ride height. You may find that the rear sits slightly lower than the front; this is normal and can be corrected with a 1-inch spacer if desired. Patience during this period ensures your lift performs as designed for years to come.
Key Takeaways
- ✓ Theopar 4-inch lift is a factory-engineered bolt-on system that preserves ride quality and warranty compatibility.
- ✓ Always use a spring compressor and proper jack stands; safety is the top priority during installation.
- ✓ Torque all suspension bolts with the vehicle’s weight the ground to prevent bushing damage.
- ✓ A professional alignment is mandatory after the lift to ensure tire longevity and safe handling.
- ✓ Allow a 500-mile break-in period before off-roading, and re-torque all bolts after the suspension settles.
Frequently Asked Questions
Will the Mopar 4-inch lift void my factory warranty?
No. Because the Mopar kit is a Mopar Performance Part, it is covered under the factory warranty when installed by a dealer. If you install it yourself, the parts are still warrantied, but labor is not. The lift will not void your warranty on other components unless a failure is directly caused by the lift.
What tires can I run with the Mopar 4-inch lift?
The kit is designed for 35-inch tires with factory wheels or aftermarket wheels with proper backspacing. Many owners successfully run 37-inch tires, but this may require trimming the pinch welds and installing aftermarket fender flares. For 37s, you should also re-gear your axles to maintain performance.
Do I need to re-gear my Jeep after installing the 4-inch lift?
Re-gearing is not required for 35-inch tires if you have the 3.73 or 4.10 axle ratio. However, if you have the 3.21 ratio, you will notice a significant loss of power and fuel economy. For 37-inch tires, re-gearing to 4.56 or 4.88 is highly recommended to restore drivability.
How long does the installation take, and what is the hardest part?
A first-time installer should plan for two full days. The hardest part is removing the factory coil springs, especially if they are rusted. The front springs are under high tension and require careful use of a spring compressor. The second hardest part is aligning the track bar bracket, which requires precise bolt alignment.
“Cars aren’t just machines. They’re freedom, memory, and a little bit of grease under your fingernails.”
I’m Theodore Roosevelt—though my friends just call me “Ted” (and no, I’m not related to the president, though I do share his love for adventure). I grew up in Detroit in the 1970s, back when the city was still the heart of the American auto industry. My first love was a rusted-out 1967 Mustang my father and I rebuilt in our garage when I was fifteen. That project taught me that cars have souls. After spending twenty years as a mechanic and another ten writing for magazines, I started this blog to help everyday drivers and weekend wrenchers feel confident under the hood. Whether you’re restoring a classic or just trying to keep your daily driver alive for one more winter, I’m here to help you get there.
