Help with new LEDs

[musigenesis]

I bought six new Grand General 7" LED sealed lights for the back of my bus. My old lights were all leaking badly due to failed seals. The problem I'm facing is how to install these so that they will be watertight. The original lights consisted of the plastic face attached to a metal plate, with a gasket between this plate and the bus skin; the lights were attached with sheet metal screws into the skin.

These new lights do not have a metal backing plate (they're all plastic plus the gasket). The skin on my bus where these lights go is now slightly warped and floppy (from some rust on the inside), so to stiffen the skin and ensure a good contact with the gasket I'm putting a piece of 1/8" galvanized steel across the holes on the inside (I'll be riveting this plate to the skin). I'm then going to put tapped holes in this plate for attaching the lights.

My problem is that the four screw holes on the lights are outside of the gasket, so I think those holes may leak a little bit. I could use seam sealer on the holes, but then I would not be able to easily remove the lights if necessary. Maybe I should use rivnuts here instead of tapped holes?

What's the best way to install lights like this in a watertight manner?

[T-Bolt]

Any auto parts store will sell sheet gaskets. They are for cutting your own if what you need is no longer available. Buy, trace, cut, install.

[musigenesis]

Originally Posted by T-Bolt

Any auto parts store will sell sheet gaskets. They are for cutting your own if what you need is no longer available. Buy, trace, cut, install.

My lights all came with gaskets. My problem is how to waterproof the screws (and screw holes) that hold the lights on.

Weirdly, BTW, when I was first trying to fix my original lights (where the gaskets had all failed and allowed serious leakage) none of the auto parts stores in my area had any sheet gasket material in stock.

[o1marc]

Originally Posted by musigenesis

My lights all came with gaskets. My problem is how to waterproof the screws (and screw holes) that hold the lights on.

Weirdly, BTW, when I was first trying to fix my original lights (where the gaskets had all failed and allowed serious leakage) none of the auto parts stores in my area had any sheet gasket material in stock.

Why not replace the original gaskets, they are readily available for a couple bucks. The screws are self sealing, why the need for more waterproofing. It's how they did at the factory, mine are still good after 20 years.

[musigenesis]

Originally Posted by o1marc

Why not replace the original gaskets, they are readily available for a couple bucks. The screws are self sealing, why the need for more waterproofing. It's how they did at the factory, mine are still good after 20 years.

The original backup lights were dead, and the other four were red (I wanted the turn signals to be amber) so I would have had to replace four anyway. My screws maybe intended to be self-sealing but weren't so the screw holes themselves are now corroded.