How to remove rust from a car

Grade the rust before you buy anything

The DIY sequence

1. 01

   Get the car up and lit

   Ramps or stands on level ground, chocked wheels, bright light. Most car rust is on the underside where you cannot see it standing up.

2. 02

   Probe before you plan

   Press firmly with a blunt screwdriver on every suspect area. Anything that gives way is a welding job, not a paint job.

3. 03

   Remove loose material

   Scrape flaking scale, wire brush the pitting, and sand bubbling paint back to a sound edge that does not lift.

4. 04

   Wash, degrease, dry

   Underbody grime is oily. Detergent wash, rinse, and let the car dry fully — trapped water in a seam will ruin the coat.

5. 05

   Mask the untouchables

   Brake lines and discs, fuel lines, rubber bushes, wiring, and any paint you want to keep.

6. 06

   Convert the rust

   Brush it into the arch lips, seam folds and pitting. A second thin coat on the worst areas after four hours.

7. 07

   Cure a full 24 hours

   Then filler if you need it for cosmetic panels, primer, colour, and lacquer — or chassis paint underneath.

8. 08

   Seal and protect

   Seam sealer over treated seams, then cavity wax inside the sills and box sections you cannot brush.

Where to look on any car

• Rear wheel arch lips, inner and outer
• Sills below the door seal, especially at the jacking points
• Floor pans and footwells under the carpet underlay
• Boot floor and spare wheel well
• Bonnet and tailgate lower edges and seams
• Subframes, suspension turrets and the rear beam

Frequently asked questions

Keep reading

• 
  Rust converter for carsTreat surface rust on car sills, wheel arches, floor pans and subframes with RustGuard™ — convert, prime and repaint without blasting.
• 
  How to paint over rust properlyPainting straight over rust always fails. Here's the correct sequence — prep, convert, cure, prime, topcoat — and the paints that work over a converted surface.
• 
  Rust converter for iron and steel that leaves a paint-ready surfaceRustGuard™ rust converter reacts with existing rust and leaves a stable, primed surface you can paint. Bundles from $24 with worldwide shipping.
• 
  How to stop rust from spreadingRust spreads because it holds moisture. Break the cycle with the right prep, a converter and a topcoat — plus the maintenance that stops it restarting.
• 
  Rust converter for motorcyclesTreat rust on motorcycle frames, swingarms, brackets and fasteners. What to convert, what to strip, and what to leave to a specialist.