Datsun Roadster Forum-311s.org

I have rust at the bottom of the panels in front of the back tires. Inside of the compartment I found lots of dirt accumulated at the bottom which I'm sure gets wet and is a chronic source of water to rust the inside. Vacuumed the dirt. No drain could be found for that compartment. Should one be added? Where? What are people using to rustproof the bottom of the compartment. Since there is no drain how would you clean that out so undercoating or POR15 could be added? I'm already using both in other areas. POR15 metal prep requires an acid wash which I'm sure is not a good thing to allow to accumulate in the compartment.

I'm finding spots where Mt. St. Helen ash has accumulated under carpets and probably in this compartment. The car was sitting out during an ash fall in the Portland area leaving 3/4 inch of ash on the car during a rain storm in 1980. The ash blew around Forest Grove all summer making a big car show in August challenging for those who did not want scratches in their paint. The ash actually scratched the windshield glass when the wipers were used.

You should have seen the POUNDS of dirt I took out of Damn it Bill's car several years back...

A good vac and compressed air blast should get things clean enough. I used SEMS Rust Seal to treat exposed rust, as all it requires is a good cleaning as indicated, then a few coats brushed in. Used it on mine 29 yrs ago on the inside without any additional undercoating and it is still fine. You could clean it up, apply the SEMS, let it dry for a day or so and spray rubberized undercoating on it, should be fine for the life of the car.

Greg, how long have you owned the car? I bought mine in 1978.

Let's see... I spied her while I was a student at Washington State University back in 1984-85 (not exactly sure as it was close to the New Year, and the cars were just big piles of snow... the only thing I could see were the tail lights, but they were enough to grab my attention).