I had posted an oversimplified albeit short step-by-step on how to replace a panel within the depths of another thread talking about endcaps. It was suggested that I post this somewhere that it would be more easily found by others at a later date, so - here goes:
If you are putting the same panels back in or new panels with holes placed from the old panels using the overlay method (see "It's a Girl!!!
" posts #227-239), 99% of the holes should
The way we did it with new panels was:
1. drill out the old rivets using an 1/8" drillbit
2. drill the new holes on the new panel(s) with an 1/8" drillbit using the old panel as a template
3. cleco everything in place back on the trailer with 1/8" clecos
4. take out every other cleco
5. drill the empty holes in place with 5/32" drillbit through the panel(s) & rib/c-channel
6. buck (or pull Olympics depending on the project) those rivets starting from the center of the panel and work out w/ 5/32" rivets
7. take out the remaining clecos
8. repeat #5-7
If you are re-using your old panels, it should be the same except skip #2. I wouldn't expect that "some holes line up and some don't", the aluminum is rigid, not really flexible enough for that. Either they will line up or not - unless it's plastic/fiberglass endcaps you are working with, which could
be more flexible. A bit of finessing may be required because ribs may have shifted or "sprung out of place" while lose, but they should be able to be put back in place and lined up with a few choice words, an extra set of hands and lots of clecos. If one or two holes don't line up, no big deal just drill them out. If it's a totally new panel with new holes, shift them so they miss the old holes - but I would definately try to use the old ones.
Hopes that helps ~