Frame Rust?

That's what i think too. Maybe just a wire brush to the areas that are flaking when it warms up.

 

*Cries in Michigan*

 

Ended up getting a deal on some cans of black fluid film. My initial brushed on FF coating during the diff service has held up really well, some spots where rust has flaked off and left exposed metal. Plan on doing a full rinse of the underside, no soap, either just water or salt gone to rinse everything out and not strip off the existing layer of fluid film. Let it dry over night, and wire brush, then touch up with the black cans and reapply to the inner frame rails with my 360 wand.

 

Anyone every use a needle gun over existing fluid film?

 

Sounds like you have concerns that some rust still exists. I would do whatever is necessary to remove all you can find, regardless of what FF is on there now, then reapply once you're confident you've dealt with all the rust. Otherwise, you might be chasing rust spots constantly.

 

Fluid film will isolate the rusty areas. I would use a wide flat head screwdriver or hard metal scraper to knock off any areas of very scaly rust. Don’t go crazy…if it doesn’t come off easily with scraper, the fluidfilm will isolate the air from rusty areas and slow it down or stop it. Fluid film is thinner than woolwax which is a good base layer. After a couple of months you can add layer of woolwax over the top, which is thicker and will stay longer.

 

It's not terrible. If it bothers you I'd just use a die grinder with a wire brush to remove heavy rust.

Spray bare areas with Steel It.

Use your choice of under body protection from there on out. Fluid film, wool wax, etc...