My only regret doing fairly extensive rust removal myself was not keeping a bucket of chunks to see how much metal I lost.
Chassis/Underside - What's your approach to surface rust removal on complete underside?
- Thread starter SMLE
- Start date
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Let me recommend a less labor intensive approach, based on my experience with a very rusty 2003 GMC Sierra.
This process will never get a vehicle back to like-new, but it is a LOT less labor intensive than pulling the truck apart, and will get you 90% of the results. Working on it after this will be very messy, but the fluid film will penetrate in and you should have much less of a problem with stuck fasteners.
- Do all the maintenance/baselining work that you want to do now. You'll probably need that induction coil that others recommended to ease fastener removal. Make sure you do as much of this as possible before proceeding, as maintenance work after coating is extremely messy.
- Powerwash the entire undercarriage, make sure to get deep into those frame rails and dead spaces. Allow to dry for a few days.
- Lanolin undercoat. I suggest Fluid Film for this, as it is a little thinner than Woolwax and might penetrate better. Make sure you get into EVERY body and frame cavity. Doors, sills, fenders, quarter panels, tailgate, etc.
- Drive it for a year. Respray the bottom once a year for a few years. You will notice that more and more rust will fall off over the months and years, revealing oily black metal.
- Once most of the rust is gone, you can switch to Woolwax if you want. It is much thicker than Fluid Film and will hold up better; you might need a coat every other year once you've built up a base.
This process will never get a vehicle back to like-new, but it is a LOT less labor intensive than pulling the truck apart, and will get you 90% of the results. Working on it after this will be very messy, but the fluid film will penetrate in and you should have much less of a problem with stuck fasteners.
I would avoid ever using any 'rubberized' coatings. All such coatings can only work if sealed against totally clean metal, and if water never (ever) gets behind them. The water WILL find a way, and then any rubberized coating acts like a poultice, keeping water/salt/rust trapped against the metal, making it rust even faster. Tar-based 'undercoating' and 'sound deadeners' fall into the same camp - do not use as rustproofing under vehicles.
As many have noted here, you want grease/oil based coatings that remain 'live' and do not cure. I'm not sure I would even attempt to paint that frame after cleaning. I would apply a grease product liberally, and flood all frame areas with ATF or ATF mixed with paraffin (heated until runny). I have literally taken axle grease from a tub, with a gloved hand, and applied to to rusty surfaces, working it into the rust and crevices. I can assure you that any rusty surface that is coated with 1/8" (ok, a couple mm for the Brits
) of grease will not rust.
Final note, no rustproofing is 'forever', so a yearly check on a lift and perhaps putting more liquid grease products inside the frame is a must.
As many have noted here, you want grease/oil based coatings that remain 'live' and do not cure. I'm not sure I would even attempt to paint that frame after cleaning. I would apply a grease product liberally, and flood all frame areas with ATF or ATF mixed with paraffin (heated until runny). I have literally taken axle grease from a tub, with a gloved hand, and applied to to rusty surfaces, working it into the rust and crevices. I can assure you that any rusty surface that is coated with 1/8" (ok, a couple mm for the Brits
) of grease will not rust. Final note, no rustproofing is 'forever', so a yearly check on a lift and perhaps putting more liquid grease products inside the frame is a must.
