Stopping the Rot: A Professional Detailing Guide to Underbody Rust Prevention

Give the underbody a massive wash. I'm talking an hour-long scrub. Use a salt-neutraliser if you've been on the beach. You want every bit of mud and grit gone.

Spray everything down with your degreaser, let it dwell for 10 mins (don't let it dry in this Feb heat!), then blast it off. This removes oils that prevent the coating from sticking.

This is where most people mess up. You cannot spray oil over water. Leave the car in the sun for at least 4-5 hours, or better yet, overnight. Use an air blower to get water out of the chassis holes.

If you see flaky rust, hit it with the wire brush. You don't need to get back to bare shiny metal if using lanolin, but you need the loose stuff gone.

Wrap your brake rotors and calipers in plastic bags. Cover the exhaust system if you don't want it smelling like burnt mutton for the next week.

Get the car up on stands. Give yourself enough room to move. Lay down your cardboard, it's about to get messy.

If it's a hot Feb day, your lanolin will be runny, which is good. If it's thick, give the tub a good shake or sit it in a bucket of warm water.

Attach the 360-degree wand to your gun. Poke it into every hole in the chassis rail. Pull it out slowly while spraying to coat the inside walls.

Don't forget inside the door bottoms, the sills, and behind the wheel arch liners. These are common rot spots on Hiluxes and Rangers.

Switch to the standard spray tip. Coat the entire exterior of the chassis rails. Work from the front of the car to the back.

Spray the control arms, leaf springs, and coil buckets. Don't worry about the rubber bushings, quality lanolin won't hurt most modern rubbers, but try to avoid drenching them anyway.

Pay extra attention to the cross-members and the area above the fuel tank. Red dust loves to sit there and hold moisture.

You want a nice, even sheen. It shouldn't be dripping off like a tap, but it should look 'wet'.

Try to keep it off the cat converter and mufflers. It won't cause a fire most of the time, but the smoke and smell are embarrassing at traffic lights.

Spray the metal inside the wheel arches. If you have plastic liners, spray behind them where you can.

Specific focus on any exposed threads. It'll make your life much easier next time you need to do a repair.

If you have bash plates, take them off, spray the underside of the engine/trans area, then spray the plates themselves before putting them back.

Go back over everything with your work light. It's easy to miss the top side of the rails.

This is the most important step. Take the bags off and hit the rotors with brake cleaner just in case any mist got through. If you don't, you'll have zero braking power at the end of the driveway.

Check the lower sills and bumpers for any overspray. Wipe it off with a microfibre and some quick detailer or soapy water.