Jeep XJ Long Arm Kit Installation | What You’re Actually In For

Most first-timers expect a bolt-on job, but a long-arm kit install on a Cherokee XJ or Comanche MJ typically requires welding, cutting, and a full suspension teardown before the new arms go in. The payoff — dramatically better ride quality, less binding, and more usable articulation on a lifted rig — makes it worthwhile when you follow the right sequence. If you are still choosing a kit, our tested roundup of the top long-arm kits covers what fits each build. Once the kit is in hand, here is what the job actually demands.

What Does A Long-Arm Install Actually Require?

Long-arm installation goes beyond a standard lift because it replaces the factory control-arm mounting points entirely. Most kits include a new crossmember or frame-mounted brackets that require welding to the unibody frame rails. Iron Rock Off Road's manual specifies wire-wheeling or grinding paint from weld areas before any welding begins, and Clayton Off Road confirms weld prep on the unibody contact points is essential.

The parts removal list varies by kit, but you will generally remove the factory control arms, brackets, and the stock crossmember or transfer case skid plate. On Iron Rock Off Road's 3-link system, the lower control arms are larger with angled male ends that must be positioned on the correct side. Cutting or grinding off factory lower control arm brackets is common, so plan for rust management and paint touch-up afterward. Brake lines, fuel lines, and electrical wiring near the factory bracket locations need careful protection during cutting and welding. Lay out all kit hardware and confirm you have the correct fasteners before starting — some kits use specific jam nut sizes like the 46 mm lower or 1 7/16 upper wrenches noted by Clayton.

The Step Order That Works

The exact sequence depends on your kit, but the documented procedure from both Iron Rock Off Road and Clayton Off Road follows this order:

• Support the vehicle securely on jack stands, ramps, or a lift, then remove the front wheels.
• Remove shocks and sway bar end links to free up suspension movement.
• Remove the transfer case skid plate if equipped, then the crossmember.
• Grind or wire-wheel all weld areas on the unibody rails until bare metal shows.
• Install the new long-arm crossmember or subframe, fitting bolts loosely at first. Center and secure it before tightening.
• Mount the control arms with correct orientation — Iron Rock specifies bent or angled ends on specific sides. Clayton says to install both upper arms together after setting caster to avoid preloading the bushings.
• Set arm lengths using the kit's measurement chart, install the joints, and leave all fasteners loose until final alignment.
• Lower the vehicle onto its own weight with the springs properly seated, then torque everything to the kit's specifications.

Torque Specs And Common Setup Mistakes

The single most common mistake is tightening suspension hardware before the vehicle is at ride height. Torquing control arm bolts with the axle hanging free preloads the bushings, causing premature wear and alignment shifts. Clayton Off Road's instructions explicitly warn that the Jeep must be on its own weight for final adjustments. Iron Rock Off Road's 6.5 in ROCK-LINK PRO torque specifications confirm all values listed below.

Other frequent errors include installing bent or angled arms on the wrong side, failing to check driveshaft clearance and U-joint interference after installation, and neglecting to bleed brake lines after suspension work that affects axle movement. Driveshaft clearance, brake line length, and differential yoke clearance should all be checked after the suspension settles. After final torque, recheck caster, center the track bar, and verify axle alignment before the first test drive.

FAQs

Do I need to weld for a long-arm install on an XJ?

Most long-arm kits for the Cherokee XJ require welding the new crossmember or brackets to the unibody frame rails. Some bolt-on long-arm systems exist, but the majority of mainstream kits from manufacturers like Iron Rock Off Road and Clayton Off Road involve grinding paint to bare metal and welding in new mounting points.

What tools do I need beyond basic sockets?

You will need a MIG welder, an angle grinder with wire wheels and cutoff wheels, jack stands or a lift, and either a 46 mm wrench for lower arm jam nuts or a 1 7/16 wrench for upper arm jam nuts depending on the kit. A torque wrench capable of 125 ft-lbs is essential.

Can I install a long-arm kit with the drivetrain in place?

Yes. The installation is suspension-only and does not require removing the engine, transmission, or axles. However, you must work carefully around brake lines, fuel lines, and electrical wiring when cutting or welding near the factory bracket locations on the unibody rails.