Symptoms
Rust where the tank meets the body, a sagging or perforated skid plate, fuel smell, a sending unit that reads wrong. Both Hagerty and YourMechanic name this area.
The fix, step by step
- Run the tank nearly empty and disconnect the battery.
- Support the skid plate and tank with a jack, remove the skid-plate bolts and straps, disconnect the filler and vent hoses and the sender wiring, and lower the assembly.
- Inspect the frame and body above it.
- Treat the rust, then refit with a new skid plate (or the master kit), insulator mat, straps and fresh hardware.
Tools & part numbers
- Transmission jack or floor jack with board
- penetrating oil
- fuel-line clamps
- sockets
Where to buy the parts
Fuel tank skid plate master kit, 1980–1991Team Grand Wagoneer ↗Amazon ↗
Fuel tank strap set, 1980–1991Team Grand Wagoneer ↗Amazon ↗
Fuel tank skid plate rubber insulator mat, 1980–1991Team Grand Wagoneer ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep Grand Wagoneer (SJ) 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.