What to seam seal from bottom?

[82Laredo]

I have the topside finished on my front floor pan replacement and had a question about what to seam seal on the bottom. Neither of these seams were sealed from the factory so I'm guessing I don't need to but figured I should ask. My thinking is they were not sealed because water could get in from other areas (like the hole in pic 1 just left of the body mount) and then not be able to escape.

View attachment 19261

This is the support that comes down from the firewall and the pan is plug welded to:

View attachment 19262

Thanks

 

[82Laredo]

I'm going to seal down the side in pic 1 and the rounded edge in pic 2 (with the tack welds; had more gap than I realized after plug welding the entire topside)

It is completely seam sealed and epoxy primered up top.

 

[PaRenegade]

I sealed mine as completely as I could, but first I sprayed those areas inside with Eastwood's internal frame paint which comes with a small 24" hose with a conical spray tip that you can fish into those obscure areas. I used the theory that if I couldn't seal an area completely then I'd leave open the lowest point for drainage, should water get in there, such as the hole right out from your body mount in the traverse support. I also used plastic drain plugs of various sizes in the many holes under the tub.
Any big holes I used a slightly larger piece of closed cell foam and squeezed it into place. This was from a 3/4" thick kneeling mat I use on the hard concrete floor. Cut the shape into cardboard for a template then make the foam a tad larger. I think these areas acted like a scoop for water and mud to get into an inclosed area. Who knows what these AMC designers were thinking!

 

[tarry99]

I have the topside finished on my front floor pan replacement and had a question about what to seam seal on the bottom. Neither of these seams were sealed from the factory so I'm guessing I don't need to but figured I should ask. My thinking is they were not sealed because water could get in from other areas (like the hole in pic 1 just left of the body mount) and then not be able to escape.

View attachment 19261

This is the support that comes down from the firewall and the pan is plug welded to:

View attachment 19262

Thanks

I hope your going to finish welding that up before you seal anything. Just a few tack welds like that will break again with all the flexing.

 

[Lumpy Grits]

I would not 'cap' those ends at all.
Leave them open to 'breath' and dry.
LG

 

[Torxhead]

Seem to have a lot of options here, i'll go with Lumpy's.

 

[82Laredo]

Thanks for the replies. I actually ordered the internal frame coating with the primer so I'm planning on using that in the open areas

The pan is plug welded from the top so it's not going anywhere.

View attachment 19266

I'm leaning towards not sealing the two areas in question since there was none from the factory there and didn't have any rust problems in those particular locations.

 

[tarry99]

All of the above..........seam sealer is OK .........But I would still finish tack welding that panel on from both sides , otherwise your floor will be flexy and whatever sealer you use down there will crack or loosen later...., then rattle can some spray undercoating into and around all of those seams under the floor.......dust, turns to dirt, then mud and once inside a seam and left to be wet & damp between those areas will rust through your metal once again.........fixed many of them. Weep holes are also a good idea in Blind areas to let the moisture out. Good Luck!

 

[Hedgehog]

Why not seal all of it, I would and leave very deliberate places for unwanted water to drain out. Sealing all the seams leaves fewer places for rust to start or grow.

 

[jammer1]

My father was a electronic engineer who designed and built equipment (some that went on the space shuttle) and always said that you leave a hole at the lowest place for water to escape. Their is always water (especially in the air) that can condense. The only way to completely eliminate water is to completely seal it air tight than pump out the air (basically create a vacuum). If you seal all the seams completely you will trap water and rot out these lower sections.