Ultimate Boat Trailer Maintenance and Corrosion Prevention Guide

Park the trailer on a level concrete surface. Chock the wheels on the opposite side of your work area. Use a trolley jack to lift the frame, then secure it with 2-tonne jack stands. Never work under a trailer supported only by a jack. Check for frame 'weeping'—rust stains coming from inside box sections—which indicates internal corrosion.

Spin each wheel manually. Listen for 'rumbling' or 'gritty' noises which indicate pitted bearings. Grab the tyre at the 12 and 6 o'clock positions and shake; any noticeable play suggests the castle nut needs adjustment or the bearings are severely worn. Document which hubs require full disassembly versus simple re-greasing.

Prepare your salt neutraliser in a pressure sprayer. For Australian summer conditions, use a slightly stronger mix than the label suggests if the trailer has been sitting with salt crust for more than 48 hours. Mix a 10L bucket of heavy-duty degreaser at a 1:4 ratio with warm water for cleaning the winch and coupling.

Disconnect the trailer plug from the tow vehicle. Open the light housings if they are not LED-sealed units. Inspect for 'green death' (copper oxidation) on terminals. In the Australian heat, plastic housings become brittle; handle with care to avoid snapping clips.

Thoroughly douse the entire frame, including the inside of C-channels and box sections, with your salt neutralising solution. Allow it to dwell for 10 minutes, but do not let it dry in the sun. This chemical step is vital because water alone often cannot break the ionic bond salt forms with galvanised steel.

Using a pressure washer, rinse the trailer from the top down. Pay special attention to the 'V' cross-members and the axle seats where salt and mud collect. Flush the inside of the box sections until the water running out of the drain holes is crystal clear. This removes the abrasive red dust common in regional Australia.

Remove the dust caps or Bearing Buddies. Pull the split pin and unscrew the castle nut. Slide the hub off the spindle. Use your degreaser and a parts brush to remove every trace of old grease from the bearings, races, and spindle. This allows for a true inspection of the metal surfaces for heat discolouration (blueing).

Inspect the rollers and races for 'pitting' or 'spalling'. If the metal looks like it has tiny craters, replace the set. If clear, pack the bearings by hand: place a glob of marine grease in your palm and 'slap' the bearing into it until grease is forced out the other side. This ensures no air pockets remain.

Always install a new double-lip marine seal. Lightly grease the spindle, slide the hub back on, and tighten the castle nut until the hub stops spinning freely, then back it off 1/8th of a turn. The hub should spin smoothly with a tiny amount of end-play. Insert a new stainless steel split pin.

For trailers with mechanical disc brakes, check the caliper slide pins. In coastal areas, these frequently seize. Lubricate pins with high-temp silicone grease. Check pad thickness; replace if under 2mm. If you have drum brakes, use a dedicated brake cleaner to remove salt and dust buildup from the backing plate.

Identify any areas where the galvanising has been scratched or depleted. Use a wire brush to remove loose scale until bright metal is visible. Clean the area with wax and grease remover. Apply 2-3 thin coats of cold galvanising spray, allowing 20 minutes of flash time between coats in the Australian heat.

Once the trailer is dry, spray a heavy coating of Lanolin (e.g., Lanotec) over all nuts, bolts, leaf springs, and the axle. Lanolin is a natural product that doesn't wash off easily in salt water and remains flexible. It penetrates the leaf spring packs where rust usually starts.

Inspect all rollers for flat spots or UV cracking. Lubricate the roller shafts with a dry-film PTFE lubricant. Avoid grease here, as it attracts sand which acts as sandpaper against your boat's hull. Ensure bunks are securely bolted and the carpet/plastic is not holding trapped salt.

Unwind the winch strap fully to check for UV fraying—a common failure point in Jan/Feb. Grease the winch gears with marine grease. Apply a small amount of grease to the coupling internal mechanism and the tow ball to prevent 'chatter' and wear during long summer hauls.

Inflate tyres to the maximum PSI listed on the sidewall (often 50-60 PSI for light truck trailer tyres). High pressure reduces heat buildup, which is the primary cause of blowouts in 40°C weather. Check for 'dry rot' cracks in the sidewalls caused by intense UV exposure.

Apply dielectric grease or a dedicated terminal protector spray to the trailer plug pins and light bulb sockets. This prevents the 'green' oxidation that causes flickering lights and indicator failures. Ensure the white earth wire is securely fastened to the trailer frame with a clean contact point.