Ultimate Underbody Rust Prevention and Corrosion Control Guide (Jan 2026)

Park on a level concrete surface. Lift the vehicle using a trolley jack and secure it on four heavy-duty jack stands. This provides the clearance needed (approx 500mm) to effectively reach the centre of the chassis. Ensure the handbrake is on and wheels are choked if only one end is raised. High clearance is vital for ensuring even product coverage later.

Use a pressure washer (minimum 2000 PSI) to blast away loose mud, sand, and salt. Pay particular attention to the 'mud pockets'—the areas behind wheel arches, on top of the chassis rails, and around the spare tyre carrier. Continue rinsing until the water running off the vehicle is completely clear. In summer, do this in the shade to prevent water spotting.

Apply your alkaline degreaser (diluted 1:10) via a foam cannon or pump sprayer. Let it dwell for 8-10 minutes, but do not let it dry—mist with water if necessary. This breaks down road oils and grease that trap salt. Follow this with an iron remover on any visible rust spots; the purple reaction indicates the chemical is dissolving the iron oxide at a molecular level.

Inspect the chassis for 'flaking' rust. Use a wire brush or a drill-mounted wire wheel to remove loose flakes until you reach solid metal or 'tight' surface rust. Protective coatings will fail if applied over loose scale as they will simply peel off. Wipe down the cleaned areas with wax and grease remover (Isopropanol) to ensure a sterile surface.

Use masking tape and plastic bags to cover the brake rotors, calipers, and the exhaust system (especially the catalytic converter). Protective oils like lanolin are flammable when first applied and will smoke heavily if they touch hot exhaust components. Also, avoid spraying rubber bushings or CV boots unless using a rubber-safe lanolin variant.

Insert the 600mm 360-degree extension wand into the factory drainage holes of the chassis rails. Depress the trigger and slowly withdraw the wand at a rate of 10cm per second. This ensures the internal 'boxed' sections—where rust usually starts—are coated in a fog of moisture-displacing wax. Repeat for all cross-members and door bottoms.

Starting from the front of the vehicle, apply a heavy coat of Lanolin (e.g., Lanotec) to all metal surfaces. Hold the spray gun 15-20cm from the surface. The coating should look 'wet' but not be dripping excessively. Lanolin is self-healing; if a rock chips it, the oil will creep back over the wound. Aim for a thickness of approximately 50-100 microns.

Apply a second, thicker layer to high-impact areas: the front-facing surfaces of the diff housings, the lower control arms, and the inner wheel arches. These areas are subjected to 'sandblasting' from road debris and require a more robust physical barrier. Use a brush to work the product into tight crevices and bolted joints.

Lightly mist the back of electrical plugs and trailer wiring looms with a non-conductive lanolin spray. This prevents 'green death' (copper corrosion) which is common in coastal areas. Unlike heavy bitumen, lanolin remains non-conductive and protects sensitive sensors from moisture ingress without causing shorts.

Allow the vehicle to sit for at least 2-4 hours before driving. In the 35°C+ heat of an Australian summer, the 'flash off' period for solvents in the wax is faster, but the oil remains tacky. Avoid driving on dusty dirt roads for the first 24 hours, as the dust will stick to the fresh coating and create a gritty paste that is difficult to clean later.

Avoid heavy coating of the propeller shaft/drive shaft. Excessive product can theoretically cause a minor imbalance at high speeds, though rare. Stick to a very light mist for corrosion protection, ensuring the grease nipples remain accessible for future servicing.

While the coating is wet, ensure you haven't obscured the brake lines to the point where cracks cannot be seen. Wipe the actual rubber lines clean with a rag; only the metal fittings should be coated for rust protection. This ensures safety inspections can still be performed accurately.

Use a high-lumen torch to check for 'holidays' (missed spots). Common missed areas include the top of the fuel tank, the upper shock mounts, and the area behind the spare tyre. A uniform sheen across all metal surfaces is the visual cue for a successful application.

Clean your spray equipment immediately using mineral turps or a dedicated citrus cleaner. Lanolin and wax become very difficult to remove once they set in the fine nozzles of a spray gun. Store any remaining product in a cool, dry place away from direct sunlight to prevent premature degradation.