lshlsh2

I Have a 71 conv. cutlass that has some rust problems (suprise suprise).

I have started on the trunk lid the lip has surface rust and some pin holes.
Do I first seal the metal with something like por 15 then smooth with body filler or vise versa. I am first sanding it down to get all the rust off I can.
I am a beginner with this type of work but have sometime to do it right.

Thanks Larry

joe_padavano

Covering the rust will only cause it to come back later. The only way to fix this is to cut out the rusty metal and weld in new. If you have pinholes, the underside is much worse and there are many more pinholes about to form. This is a very common rust area on the 70-72 cars.

Your best bet is to get a good used lid. You are in luck because the 4door trunk lid is the same as the one on the convertible. (Which is why you see so many "convertible" trunk lids for sale on ebay - they all came off of 4dr parts cars). You can use any 1970-1972 convert or 4dr trunk lid.

Texascarnut

There is really no such thing as "minor" rust problems. As Joe points out it will always be worse underneath because that is where the moisture accumulated to start the problem in the first place. It's caused in this instance by condensation that had no way to drain or dry out. A typical problem with deck lids of all makes in the 1970s made worse by poor quality steel being used because that was all the automakers could get. As Joe said the best thing to do is replace it. Preferably with one known to have come from a dry climate area and then it would still be best to inspect before buying.

Olds64

Joe is right; however, even if you buy another trunk lid the rust is going to come back eventually. Depending on your budget and what you want from the car should determine your course of action.

The best bet is to replace the trunk lid.

If you can't do that then maybe you could get a friend to help you cut out the rust and weld in patch panel. Then smooth the panel from there.

Finally, if you can't weld and can't afford a turnk lid then you can do what you said. I've found that POR 15 is great stuff. I did a similar project on the window channel of my 71 98. I am happy with the results. Sure the rust might come back since I didn't completely get rid of it, but it will take a million years to get through that POR 15.

lshlsh2

Thanks all
I'm going to try the por 15 route. Money is tight right now. Root canel for me and a daughter about to start collage. It is a long term project that is going to be a driver. I think I will fix this one and keep my eye out for a replacement. Replacing the quarters and part of the trunk is more pressing. The trunk lid can be a learning experience.

ent72olds

If there is a way to get to the back side of the affected area, you could POR 15 that also, then do what you need to on the outside. Remember, POR 15 is a rust converter...it likes rust, not clean metal. Even if you got a replacement decklid, it WILL BE rusty in there as there was poor coatings used from the factory back then. Unless you get an aftermarket(not sure if it is made?) with E-coat protection on it, you are going to have what you have...

joe_padavano

Correct. You can inject or pour the POR15 in between the inner and outer panels of the trunklid at the bottom. Then, apply the POR15 to the outside before any filler. If you have pinholes, consider the POR Putty.

rockethound

i sand blasted the inner lip and then beat the hell out of it nocking out the loose stuff pealed the cut and pealed the seam back sand blasted again prept the area welded it back to geather.

rockethound

and they are write about the four door lids probably going to be easier to buy a rust free