QuestionI have a 69 Deville convertable. I knowhow to take care of the mechanics, but the underbody - well I would like some advice.
The car is operating and I drive it usually daily. I bought from my Son-In-Law who had it at college. I think I am the third owner. It is not in real bad shape and runs fairly well. I replaced the top myself and the top's frame is now in good shape. And the body is not bad except as I will explain.
The body and frame have varying rust. Some areas, such as near the engine and transmission, are preserved because of oil deposits. And I know the usual lower part of the rear of the front fenders is bodyshop work as is the rust thru now coming at the rear fenders rear lower area.
But what would you recommend for undercoating to preserve the underside and door insides. I recall the old undercoating of the sixties and before and they didn't do much.
Would appreciate some advice.
Sam
AnswerI do not recommend undercoating, as I think it does more harm than good. For inside the doors, you can use some as sound deadening, just make sure the drain holes are open so you don't trap moisture in there. Generally, you are much better off keeping metal where you can see it and keep it clean.
I don't know where you live and drive, but out here in the dry southwest, painted metal lasts just about forever. If you are in the east or northern tier states where they use salt on the road, the best practice is to not take it out in those condition, but if you have to, then hose off the complete underside of the car immediately. Of course coat any bare metal with a good paint after you get it totally clean - plain old Rust-O-Leum gloss black does a good job of protecting clean metal.
Where you already have some rust starting (under the car and in areas where you don't need to have a nice finish, use either Corroless or POR-15 to coat the affected areas).
In areas where there is old repair failing, or rust is bubbling through the paint, and you DO care about appearance, you really need to remove all that and cut out the rusted metal, then wire weld in replacement panels, coat the whole area with epoxy primer (DP-40), and finally paint it.
If you have rusty metal in any structural area (like spring anchor points, frame rails etc.), the car is really not safe to drive - it's time to let it go and find a better example. Out here in the southwest, rust free cars are easy to find - don't take a chance on a structurally questionable car.
Dick
