BELLY Pan Question

[blackbetsy51]

Hey Guys, my buddy and I were getting all the old fiber glass out, and he lost his balance and stepped on the belly pan ( it was after a few beers). anyway, what would be the easiest way to repair where the screws tore through the belly pan. i was thinking maybe fiber glass and then re-drilling, but i do not know.

[robwok]

To get this right, you were inside the trailer, and removing the floor, and then stepped through the belly pan which tore around the heads of what was attaching it to the bottom of the frame?

Best option is to rivet a patch. The belly pan is aluminum. You can get aluminum flashing from Lowes, double it up, then rivet it on. Since it sounds like you have access to the inside, put this lighter duty aluminum to the inside of the trailer. You may want to bend any torn aluminum into the trailer so it has some spring tension against your patch. Use aluminum rivets.

Should be barely noticeable from the outside if you do it right.

I have a couple holes myself on my trailer, but I saved pieces from when I cut out the roof for my new AC, so I'll be using those.

[Wingeezer]

Can't quite picture the situation, but what about using large diameter stainless steel fender washers? Would that work?

Brian

[blackbetsy51]

correct we were inside, standing on the frame, and he stepped on the top left section of the belly pan.
- i understand how you are explaining to patch, but when he stepped on the belly pan it became detached from the actual body of the trailer.
how would you suggest re-attaching the belly pan to the body?

[garthbf]

drill out the old rivets and then use these.
Large Flange Rivets

[Lumatic]

Aluminum, especially the belly pan, can corrode and oxidize over time. If the belly pan is now off, would it be a good time to replace the whole segment with new aluminum?

[robwok]

The belly pans are just riveted on. Usually belly pans corrode due to salt from the road (or mouse urine), but many are torn off because they're hanging down and get caught.

My trailer was in excellent condition, but the belly pan was lose in some areas because the original rivets had corroded.

In the upper parts of the trailer, the inner and outer skins are aluminum sheets riveted to aluminum frames by aluminum rivets.

Underneath, it is aluminum sheets riveted to a steel frame by aluminum rivets. The rivets corrode, and the aluminum touching the metal frame corrodes. Since the rivets hold the bellypan in specific points, many times the rivet, and a small circle around the rivet will corrode so that you're left with a larger hole for the new rivet to try to capture.

The answer lies in using the very large head belly pan rivets. Don't use screws. You're opening yourself and others to problems when those screws fall out near tire traffic. The holes are already there. If you don't order the large head rivets, you can get by with stainless fender washers, or maybe a combination of washers.

Use the patches for big holes, then drill new holes in solid skin through the belly pan and through the metal channel, then attach a rivet in a solid section.

Though it's nice to replace the belly pan, if it doesn't have obvious holes and corrosion, it's not bad to keep it where it is. If you're not doing a shell off now, you can always replace the skin at a future date. I would even patch it a couple times before I'd replace the whole thing myself.

[Argonaut20]

If I understand correctly, the belly pan pulled out at the side where it is sandwiched between the outer skin and the C channel for the frame. You will have to drill out the rivets for the side skin of the trailer, pull the skin out until you can slip the belly pan into place again, then re-rivet with Olympic rivets. You might be ahead to make a patch to replace the part that tore out, rivet it to the existing belly pan, then slip the patch into place, drill, and rivet. That way you have fresh rivet holes in the pan rather than the torn holes.

[DryFly]

Originally Posted by blackbetsy51

correct we were inside, standing on the frame, and he stepped on the top left section of the belly pan.
- i understand how you are explaining to patch, but when he stepped on the belly pan it became detached from the actual body of the trailer.
how would you suggest re-attaching the belly pan to the body?

So it sounds like you're replacing plywood flooring using a shell on method? If you are going to all that trouble, why not get rid of the original belly pan and put a new one on? It's not that difficult, especially compared to what you are evidently doing now, and not all that expensive. Once done you should be good for another 40 years or so.

[blackbetsy51]

lol, yes this is obvisouly my first refurb.
how do you replace the floors with the shell off?
i'm going to hold onto the originanl belly pan for now, the rest of it is in pretty decent condition.

[perryg114]

You do know that to replace the floor it has to go between the shell and the frame? The belly skin is the lower flat part and the side skins are what we call side wraps. These are separate pieces that are bent around the outriggers to form that round shape. These start at the seam under the bumper trim. It is best to use the old wraps as a template and then pop rivet the new section along the seam at the top just like the old wraps were riveted. At the bottom you will have the side wraps and the belly skin riveted to the main frame rails. You can piece together the belly skin as long as you have a cross member or frame rail to rivet to. That is where the large head rivets come in but I prefer to use screws.

Perry

[blackbetsy51]

https://www.facebook.com/evan.padron...6618518&type=3

[Clopticon]

Cool pics! What size is your trailer? It looks like a 30 footer. I've got one too and I would like to do a rebuild of the frame, floor and belly pan. How long did it take you to pull out the old floor, cabinets and insulation??

[blackbetsy51]

1 week and a lot of beer. ive learned working alone is always better. good luck, hope to see pics. i will upload my progress soon. i have insulated the floors and threw down .25' pine, with sanding sealer and a poly finish. installed a new breaker box, now going to mess with the bathroom for awhile. thinking a tankless water heater.

[Colin H]

Originally Posted by blackbetsy51

https://www.facebook.com/evan.padron...6618518&type=3

Based on these photos, you've only removed a couple of the inside wall panels & none of the bellypan. Keep in mind that the body is held to the frame with bolts around the perimeter that also pass through the plywood floor. You must remove the perimeter bellypan, at a minimum, all of the way around in order to install the bolts & nuts. This is critical in order to maintain the structural integrity of the semi monocoque structure.
Colin