Rocker rust is structural on the early Bronco. The rocker sill connects the body at the door hinge pillar and kick panel — if it's gone, the door sag shows it. Fix rockers before rehanging doors.
Rockers on an early Bronco rust from the inside out — trapped moisture in the closed section corrodes the inner rocker while the outer skin still looks presentable. Probe the rocker with an awl before buying. Soft or hollow means the inner structure is gone.
**Severity classification:**
**Repair procedure:**
1. Remove door(s) to access the rocker end fully.
2. Cut out the damaged section back to solid metal — 1–2" into solid metal on each end.
3. Treat exposed metal with rust encapsulator. Allow full cure.
4. Fit the new section, check door gap alignment before welding. The rocker sets the door's lower hinge geometry.
5. Stitch-weld in with weld-through primer on lap joints.
6. Inject 3M cavity wax into the closed section of the new panel through a small drilled hole (plug it after). This prevents recurrence.
**After repair:** Cavity wax on all closed body sections — rockers, door bottoms, A and B pillars. This is the #1 prevention step for long-term rust resistance.
| Part | Vendor | Est. price |
|---|---|---|
| Early Bronco rocker panel sections (pair) | AMD / Bronco Graveyard | ~$280 |
| 3M cavity wax (aerosol, for closed sections) | 3M | ~$30 |
| Eastwood Rust Encapsulator (quart) | Eastwood | ~$30 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.