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Rust under door sill protector

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Omnibug, Jul 5, 2014.

  1. Omnibug

    Omnibug New Member

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    Hey all,

    I removed the driver-side door sill protector today, and discover some rust around the rectangular holes where the tabs of the protector get inserted. There are also small rust bubbles in the paint. (Small as in 1/16" in diam.)

    Has this occurred to anyone else too?



    Thanks!
     
  2. robert mencl

    robert mencl Member

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    Hi Omnibug, I use a product called Fluidfilm, you can get it at local auto parts or off Ebay, comes in a spray can with a wand like WD-40, but the oil is sticky like chainsaw bar and chain oil. You apply it after the weather has been dry for several days, so the seams between sheet metal are very dry to facilitate capillary wicking action.
    Under your car are a bunch of small plastic plugs, especially in the rocker panels. You put your car on a lift and spray in these places, and inside the door bottoms, and anyplace else you see rust. 1 can does a whole car. No need to sand and paint the rust, it will stop in it's tracks. Good luck! Robert
     
  3. Mike500

    Mike500 Senior Member

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    Once the rust has started, it needs more preparation than just rustproofing.

    You need to use a "rust converter" to stabilize the rust. A phosphoric acid converted will turn the rust into iron phosphate.

    Then, you can apply rustproofing.
     
  4. Omnibug

    Omnibug New Member

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    Hi folks,


    Thanks for the tips! What really bugs me is that the rust is happening under a part that wasn't meant to be taken off.

    After all:
    1) the plastic sill protectors are meant to protect the door sill, but now they are actually adding a weak point were rust will start;
    2) under normal use, by the time an ordinary driver detects rust coming from under the door sill protector, the entire rocker panel might be in pretty bad shape.

    Does that mean that removing the door sill protectors periodically for rust checking should be part of the routine maintenance?


    :coffee:
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    How easy was the door sill removal?

    (and thanks for the heads-up)
     
  6. Omnibug

    Omnibug New Member

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    It's pretty easy!

    You just need to pry them off with your fingers, using a wiggling motion to ease the underside tabs out of the mounting holes. I've read elsewhere on the forum that you can also use a plastic spatula to pry them off.
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah, I had a look, using a putty blade with masking tape. there's 3 tabs. Also helps a bit to pop-up the plastic sill trim partially, and pull up a bit on the rubber gasket. Our driver's door one looked fine. Maybe being that you're in the snow belt, getting a lot of moisture on that ledge with salt as well. Thanks again for the tip.

    To your gripe: a lot of trim pieces are like that, meant to protect, and end up promoting rust. Door protection strips for example, especially the ones with similar body openings for clips. They're really out in the weather, rust-prone.
     
  8. Mike500

    Mike500 Senior Member

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    These areas are traps for water and salt laden electrolytes and every form of water absorbing organic detritus.

    Whenever I get a new car, within days, I spray these cracks with a thin rustproofing into these cracks.

    Transtar Body Tec Amber Rustproofing 4423 | eBay

    Dust, salt, dirt and organic detritus gets between the flexible plastic and the metal. It's like the paint and zinc reust resisting coatings "sand off" the protecting paint and zinc layers.

    Waxy rustproofing acts as a lubricant on which the flexing material slides. It also keeps moisture laden salt from entering.

    Body panels are well protected by zinc coatings and painting. It's the join arrears that are most vulnerable.

    The spray cans comes with small wand straws like WD40 cans. It takes almost no special skills to apply. But, it does pay off a lot in the long run.
     
  9. Omnibug

    Omnibug New Member

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    I actually suspect that the previous owners probably banged their snow-covered boots on the door sill as they enter the car. I can see some salt residue on the carpeting along the edge of the floor's plastic moulding, just inside the rubber weather stripping, despite the dealer's best attempt to clean all that stuff off.

    Oh, BTW, I got this car only a month ago :)

    I also pulled up the weather strip a bit on the driver's side, and saw some small rust spots too on the rib on which the weather stripping clips onto. I'll nip those in the butt too.

    Thanks for the tip on the products, going to look them up and if they're available up north.
     
  10. Omnibug

    Omnibug New Member

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    Hey folks,

    Just an update: I did the required fixes today: removed the door sill protectors, scrapped off the rust, applied the rust converter, then sealed everything with rustproof paint.

    There is one surprise though: out of curiosity, I peeled off the weather stripping, and found an 1-in long strip of line on the flange where the strip sits. The flange is uniformly covered with body colour paint, except for one 1-in w portion which only has the gray primer. This is the area where the rust line formed. I found this both on the driver and the passenger side.
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    I'm not quite understanding, are you thinking it's been repainted? There's no way factory painting would be done with weather stripping in place. Not the end of the world, but good to know.
     
  12. Omnibug

    Omnibug New Member

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    I suspect that the primer-only area might have been where the frame was gripped for the painting process when the body color was applied, and the clamping/gripping effector end occluded that spot.