Comprehensive Undercarriage Protection and Corrosion Prevention Guide (Jan 2026)

Ensure the vehicle has been stationary for at least 3 hours. Spraying cold water or chemical degreasers onto a hot exhaust manifold or brake rotors can cause thermal shock, leading to warping or cracking. In 40°C+ heat, work in a shaded area to prevent cleaning products from drying prematurely on the surface, which causes chemical staining.

Lift the vehicle using a trolley jack at the manufacturer-specified lifting points. Place the vehicle on four heavy-duty axle stands. Test the stability by giving the vehicle a firm shake before ingress. Increasing the ground clearance is vital for ensuring the spray pattern of your protection products reaches the top of the chassis rails.

Use a dry brush or compressed air to remove loose clumps of mud or dry red dust. Removing the bulk of the 'dry' contamination first prevents the creation of a thick mud slurry during the wet phase, which can push grit deeper into sensitive seals and electrical connectors.

Mix your salt neutraliser and degreaser according to the manufacturer's instructions. For heavy red dust, a 4:1 water-to-degreaser ratio is often required. Fill your foam cannon or pump sprayer. Ensure you have adequate lighting, such as a portable LED work light, to inspect deep crevices within the frame.

Perform an initial rinse using a pressure washer. Start from the front of the vehicle and move backward. Focus on the 'mud traps': inside the chassis rails, on top of the fuel tank, and behind the wheel arch liners. Use a sweeping motion to dislodge surface contaminants without forcing water directly into electrical plugs.

Apply the heavy-duty degreaser to the entire underbody. Let it dwell for 5-7 minutes, but do not allow it to dry. The degreaser breaks down oil films and organic matter (like bug splatter and grease) that prevent the protection layer from bonding to the metal. Use a nylon brush on stubborn areas like the differential housing.

Apply the salt neutralising solution. This is a critical step for vehicles driven on beaches or salted alpine roads. The solution chemically reacts with sodium chloride to break its bond with the metal. Allow it to sit for the time specified on the bottle (usually 5-10 minutes) before a thorough rinse.

Using your stiff-bristled brushes, scrub the hard-to-reach areas where red dust accumulates. Pay special attention to suspension turrets, leaf spring packs, and the area above the spare tyre. Red dust is often slightly acidic and highly abrasive; removing every trace is essential for long-term protection.

Rinse the undercarriage until the water running off the vehicle is perfectly clear. Any remaining soap or degreaser will interfere with the adhesion of the Lanolin or wax coating. Use an underbody wash tool to ensure the top surfaces of the chassis are flushed.

Use a leaf blower or compressed air to remove standing water from recessed areas, bolt holes, and electrical connectors. Trapping water under a protective coating is counterproductive and can lead to 'cancerous' rust. In high humidity, allow an extra hour of ambient drying time.

Cover the brake rotors, calipers, and the exhaust system (specifically the catalytic converter and DPF) with plastic bags or masking paper. Protective coatings like Lanolin are flammable and will cause smoke or odors if applied to the exhaust, and will cause brake failure if applied to friction surfaces.

Apply your chosen protection product (e.g., Lanolin-based spray). Hold the nozzle 15-20cm from the surface and apply a thin, even coat. Ensure you spray into the 'drain holes' of the chassis rails to coat the interior. The coating should look 'wet' but not be dripping excessively.

Using a long extension wand (often provided with professional kits), inject the coating into the internal box sections of the chassis. These areas are where rust usually starts because they trap moisture and salt but are never seen during a standard wash.

Check the exterior paintwork and lower trim for any over-spray. Use a microfiber cloth and a gentle quick-detailer to remove any oily residue that may have drifted onto the body panels. This prevents dust from sticking to the visible paintwork.

Allow the coating to cure for at least 2-4 hours before driving. Most Lanolin-based products need time to 'set' and become tacky. Driving immediately on a dusty road will cause the dust to embed into the fresh coating, creating a sandpaper-like finish.

Use a torch to inspect the coverage. Look for 'dry' spots that may have been missed. A properly coated undercarriage will have a uniform, slightly amber or satin sheen. Re-apply to any missed areas to ensure a continuous barrier.