Ran into something that you might want to check on you Montanas. And don't limit your search to the satellite prep but also the black water flush faceplate as well. (My flush faceplate was caulked but replaced the screws that were starting to rust with the aluminum ones (Treated with caulk of course!).
The screws on the external faceplate that provides the connection for an external satellite dish showed signs of rust. I removed the three screws and found them to be nearly rusted in half! The reason they rusted was because Keystone had not put any caulk on the screws nor between the side of the 5er and the faceplate. To add insult to injuy, the faceplate was positioned directly below the downspout from the roof and got totally soaked whenever it rained.
I cleaned the rust off the faceplate with SoftScrub and put some caulk on the rear of the faceplate before reinstalling it. I also put a dab of caulk on threads of the screws (close to the head of the screw) to create a seal between the screw head and the faceplate.
Looks good and now I don't have to worry about water getting in via this route. Judging from the rusted screws I believe that quite a bit of moisture came in this way. Bummer!!
As an aside, I had a terrible time finding white headed, square drive screws to replace the rusted ones. At Lowes Home Improvement they cnly carried #10 by 1" aluminum. At an RV dealer I got some #8 x 1 1/4" steel screws. I used the aluminum screws on the satellite faceplate. (The old screws were steel #10s 1" long.)
I also found out why Keystone doesn't use aluminum screws. They are more expensive and they break! I tried replacing another one of the trim screws that was starting to show signs of rust. But this screw was a #8 1" long. The aluminum screw turned part way in without complaint but then tightend. I applied a tad more pressure and the screw broke off. Now I will have to remove the trim one of these days and possibly "easy out" the broken screw. Moral of the story .. When peplacing #8 screws with #10 aluminum ones, drill the hole out just a tad before screwing the #10 aluminum screw in! Live and learn!!!
Craig
'01 Chevy K3500 Dually 8.1 Allison 4x4 4:10 CC
Towing a '02 Montana 3655FL 5th Wheel
Manassas, Virginia USA
http://users.erols.com/jcmccarter/index.html