I had some driver's side bottom lip rust under the removable bottom door lip molding. This has to come off and you will need a new molding as they bulge open with the rust in the spaces. Anyhow, I cleaned off all the loose rust with a wire brush and sandpaper. You have to also scrape off the loose pieces. It does not have to all be real shiny. Then I used 2 key products. First, brush on a coat of phosphoric acid available at all auto body shops--real cheap. Trade name is:OSPHO. The metal will turn grey/black as the iron oxide is converted to iron phosphate, a more stable and inert oxide which binds up all present corrosion. Give it 2 coats after it dries 24 hours. Then, lightly sand off any haze and wash with alcohol to neutralize and de-grease. Then apply 1 coat of the best rust paint in the world--POR-15. www.por-15.com . I am not a salesman! This dries to a tough ceramic like hardness. The rust will just not come back if you get it all covered. Don't get this on your hands--it takes a week to come off! Then apply your new molding--as good as new.

• Door Bottom Rust Repair-- Any advice? - Eric Clark 2008-04-24 17:22:04 (147 views)
  • Repair detail (pic) - kfister 2008-04-27 01:19:57 (162 views)
  • This is what I did - 525i 2008-04-26 23:51:27 (102 views)
  • Re: Door Bottom Rust Repair-- Any advice? - daveinmiami 2008-04-25 13:46:40 (111 views)
  • How much work do you want to do? Any holes? - kfister 2008-04-24 21:50:40 (107 views)
    • The rust is new - Eric Clark 2008-04-25 16:01:33 (72 views)
      • Re: The rust is new - kfister 2008-04-25 17:05:16 (69 views)
        • Re: The rust is new - Eric Clark 2008-04-25 19:21:42 (70 views)
          • Same thing different media - kfister 2008-04-25 21:50:28 (65 views)
    • Re: How much work do you want to do? Any holes? - cloudnine 2008-04-25 10:36:19 (76 views)
    • Hey! I'm Oxford green too! - e34jef 2008-04-25 08:01:26 (70 views)
      • I am planning on painting the whole car next year - kfister 2008-04-25 12:20:19 (72 views)
  • Re: Door Bottom Rust Repair-- Any advice? - yaofeng 2008-04-24 19:14:31 (85 views)
    • Re: Door Bottom Rust Repair-- Any advice? - zorrow 2008-07-30 16:37:10 (32 views)
    • did that 4 years ago and still o.k. - shogun 2008-04-24 21:44:32 (92 views)
      • did similar on underside of sunroof - russell36 2008-04-25 08:59:07 (73 views)