Pin holes
 

Here's a little info on galvanic corrosion on aluminum. There are those who make temporary repairs (myself included), but here's why we CAN'T stop those pesky pin holes. Pictures please...
First pic back of the paneling touching the metal roof. The dust from the galvanic corrosion is the white stuff. The pic with the "rust" around it is the actual pin hole from inside, and the last pic is the actual pin hole.
Because the inside of the aluminum was not even primed much less alidined (sp), there is no way to prevent the spread of the corrosion. Unfortunately, we can't stop this from happening. But we can help by keeping our roofs clean and coated with such products as Kool Seal or Henrys etc.
The powder you see in the last pic is the start of corrosion throughout the roof. Later this summer this roof will come off and a rubber roof installed.
Hope this helps just one person.
Treeclimber

I had many pin holes in the aluminum roof and to stop the erosion process, I used duct tape on the metal frame then patched the holes. This has seemed to work for 4 years now. Cause Metal and aluminum can not touch without erosion.

Hi TREECLIMBER
I agree with you there is nothing to do, except to have a sacrificial anode in zic that I do not know where to place it. I have started to change my roof and I will use a RMA Xtrm Ply PVC roof. I have not seen a discussion of this product in the forum. Good Luck.

FR, Dicor sells a complete kit on amazon that we used on a 27'er and on a 20'er. The owners and myself were very satisfied with the procedure and the results. They also provide a youtube video of the how-to, from start to finish. However, they "replaced" a rubber with rubber. We replaced a metal roof with rubber. We installed marine grade 3/8" ply, then followed the youtube for the rubber install. After the prep work, the install took about 2-1/2 hours being overly cautious. The finish work and caulking took another couple hours. One day. I'll sick with Dicor, but, I'll get it from their website, fresher product.
Tree

Pin Holes in walls.
 

J&R told me how to fix water damaged walls. This was done on our 1990 HiLo. First thing is to realize that after your HiLo is a few years old you need to remove all windows and relign with butyl tape and Lexel caulk. Any water damaged walls can be ripped back to the fiberglass(Classic model). Any rusty frame is to be wirebrushed and coated with Rustoleum or like product. Bondo is to be applied to the interior of the fiberglass wall. Use an industrial respirator and follow all the directions on the can. Cheapest at Walmart. This seals up any pin holes that you can't even see. After our repairs we had no leaks. We kept the HiLo for several years. Our current HiLo has a metal roof. If we need to replace it my preference would be a rubber roof like our first HiLo. Best of luck with any repairs.