Symptoms
Flaking, swollen or holed frame around the rear lower control-arm brackets, the transfer-case crossmember or the central body mounts. Quadratec's correspondent found all three on a 1998 TJ with 190,000 miles.
The fix, step by step
- Only for someone who can cut and weld.
- Support the frame on stands, jack the axle, then unbolt the upper and lower control arms on one side, the sway-bar link and, if needed, the shock.
- Mark at least 1 inch of overlap and cut out the rotten section and the old arm mounts, without cutting the body mount and keeping clear of brake and fuel lines.
- Mock up the new section, grind to bare metal, measure, tack, measure again, then weld it fully.
- Prime and coat it, and refit the arms with thread locker and correct torque.
- Re-check after a day, or a mile, and then monthly.
- One side at a time.
Tools & part numbers
- Welder
- cutoff wheel and grinder
- jack stands
- floor jack
- torque wrench
- thread locker
- rust-proof coating. Rust Buster sections are side- and year-specific (2003–06 differ from 1997–02).
Where to buy the parts
Rust Buster full center frame with trail-arm mount, 2003–06 TJ (left)Quadratec ↗Amazon ↗
Rust Buster full center frame with trail-arm mount, 2003–06 TJ (right)Quadratec ↗Amazon ↗
Rust Buster center frame skid-plate mount, 2003–06 TJQuadratec ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep Wrangler Unlimited (LJ) parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.