I am mounting an amp behind my rear seat in my 2004 supercab. Its a big amp, and I can't get it too fit if I use wood, or mount where there is the double sheet metal. Will it be ok to drill through the sheet metal to the outside? Should I put silicone on the screws or something?

 

I'm sure plenty of people have gone through the exterior sheet metal, but I wouldn't. I've seen several very large amps mounted behind the rear seats without going throught the exterior wall. If you're creative enough, you CAN fabricate something that will work.

What I'd do (did) is cut a peice of wood a little bigger than the amp's footprint. Then first mount the wood to the rear wall, attaching only at the points where there is double-wall. After the wood is secure, then you mount the amp directly to the wood. It shouldn't be a problem.

 

if you go threw the cab use a big fender washer on the outside and i would put a dab of silicone around it so it doesnt leak and get your amps wet

 

I mounted these two large amps without drilling through the outer sheetmetal (I appoligize for the lousy quality, I took it in a hurry a few minutes ago).



If you remove the cover on the back wall you will see a stamping spot welded onto that wall. You can drill through this and mount the amp without going through to the outside. Then you can do what I did and trim the cover around the amp(s), this will allow the amp to sit flat.