Symptoms
Flaking scale where crossmembers meet the frame, holes behind the rear axle, a spare carrier that won't release or sags.
The fix, step by step
- Salt and debris pack in between body and frame and rot the rear crossmember from the inside — often discovered when the spare won't come down.
- Cut out the rotten section and weld in a replacement such as the Rust Buster 11-gauge crossmember (replaces Toyota 51209-35171), then treat surrounding metal with rust converter and a yearly oil- or grease-based inhibitor.
Tools & part numbers
- Welder
- angle grinder
- Rust Buster crossmember
- rust paint
- inhibitor spray
Where to buy the parts
Rust Buster 11-gauge spare-tire crossmember, 1996–2002 4RunnerLiftKits4Less ↗Amazon ↗
Rear frame crossmember sub-assembly (Toyota 51209-35171)ToyotaPartsDeal (Toyota OEM) ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Toyota 4Runner 3rd Gen 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.