Comprehensive Boat Trailer Maintenance and Corrosion Prevention

Before beginning the deep clean, perform a visual 'walk-around' while the trailer is empty. This allows for a clear view of the rollers, skids, and inner frame rails. Look specifically for 'tea staining' (early rust) on welds and check for any cracked galvanising. Note any areas where the red dust has accumulated, as this traps moisture against the metal.

Position the trailer on a slight incline if possible, with the hitch raised. This ensures that water and cleaning solutions flow out of the rear of the box sections and don't pool inside the frame. Ensure you are working on a concrete pad or hardstand; avoid grass as the salt runoff will kill vegetation and the moisture from the grass will promote underside corrosion.

Prepare your salt neutraliser according to the manufacturer's ratio. For heavy summer use, a 1:500 ratio in a dedicated mixing unit (like a Salt-Away mixer) attached to your hose is standard. If using a spray bottle for targeted areas, a stronger 1:100 ratio is more effective for breaking down stubborn salt crusts on brake assemblies.

Chock the wheels securely. If you plan to check bearings, ensure you have a trolley jack rated for the trailer's ATM (Aggregate Trailer Mass). In extreme heat, tyre pressures will increase; check pressures when the tyres are cold to ensure they meet the manufacturer's specification (usually 45-60 PSI for light truck trailer tyres).

Begin with a thorough high-pressure rinse using fresh water. Focus the spray into the drainage holes of the box sections. In coastal areas, salt particles are microscopic and wedge into every crevice. Spend at least 10 minutes on this phase, ensuring the water running out of the frame transitions from cloudy/salty to completely clear.

Switch to your salt neutralising solution. Apply it to the entire frame, starting from the hitch and moving backward. Pay special attention to the 'leaf spring' packs and the back of the brake backing plates. Unlike water, these chemicals break the chemical bond salt has with the metal. Leave the solution to dwell for 5-10 minutes, but do not allow it to dry in the sun.

Apply a heavy-duty alkaline degreaser to the wheel hubs and rims. Use a stiff brush to agitate the mixture of old grease and road grime. This is critical because grease contaminated with salt and dust acts as a sandpaper-like abrasive on your bearing seals. Rinse thoroughly until the metal surfaces are 'squeaky' clean.

Leaf springs are the most common failure point due to 'pack rust'—where rust expands between the leaves. Use a wire brush to remove loose scale. Once dry, apply a liberal coating of Lanolin spray. Lanolin is hydrophobic and will creep into the gaps between the leaves, providing a barrier that water cannot penetrate.

For trailers with mechanical or hydraulic brakes, check the slide pins and callipers. Salt often causes these to seize in the 'on' position, leading to overheating. Apply a small amount of high-temp nickel anti-seize to the moving contact points, being extremely careful not to get any on the brake pads or discs.

If you have 'Bearing Buddies' or similar protectors, check the spring tension. If the piston is bottomed out, add marine grease using a hand grease gun until the piston moves outward about 3-5mm. Do not overfill, as the pressure can blow out the rear inner seal, allowing salt water directly into the bearings during the next launch.

Open the 7-pin or 12-pin plug. Inspect for green corrosion (copper oxide) on the terminals. Use a dedicated electrical contact cleaner to spray the pins. Apply a small amount of dielectric grease (silicone grease) to the terminals to prevent moisture ingress and 'stray current' issues which often cause flickering LED lights.

Unwind the winch strap or cable fully. Inspect for fraying or UV degradation. If using a steel cable, wipe it down with a Lanolin-soaked rag. Lubricate the winch gears with a heavy-duty water-resistant grease. A seized winch at a busy boat ramp is a common but preventable summer disaster.

Identify any areas where the galvanised coating has been chipped or scratched, exposing raw steel. Use a Scotch-Brite pad to clean the area back to bright metal, then apply two coats of 99% Zinc Cold Galv spray. This provides sacrificial protection, preventing the rust from 'creeping' under the healthy galvanising.

Trailer tyres rarely wear out from mileage; they fail due to UV-induced sidewall cracking (dry rot). Apply a high-quality, non-silicone tyre dressing that contains UV blockers. Avoid 'shiny' solvent-based dressings which can actually accelerate the leaching of protective waxes from the tyre rubber in extreme heat.

Check that all rollers spin freely. If they are 'flat-spotted', they must be replaced. Apply a silicone-based spray lubricant to the roller axles. Do not use grease here, as it attracts sand and grit which will eventually jam the roller and scratch your boat's hull.

Once the trailer is completely dry, apply a 'soft' coating like Lanolin or a dedicated frame wax to the internal box sections using a long-reach wand. This is the single best way to prevent the trailer from rusting from the inside out, which is the leading cause of structural trailer failure.