I sent you an e-mail about a year ago about a leak I had in a 27.5’ fifth wheel. This is an update as to what I found out and how I fixed the problem.
I opened the back wall on the inside of the trailer and the insulation was wet, which I removed. The area around the tail lights was dry with no water stains. However, the 2×2’s in both corners were black. I went to the outside of the trailer (at the rear) and removed the trim that is used to cover the screw heads. Along the top of the roof are radiuses and there was a hole at either end with no screw in either one. So, water must have entered through the holes, and leaked in behind the trim and down inside the wall, turning the 2×2’s black. So, I replaced the 2×2’s, screwed in new screws (with caulking) and now everything is all dry. I would like to thank Ian Mundy for his article on leaky tail lights and thank Garth Cane for publishing these articles.
My next question is what is the rule of thumb for changing trailer tires? I replaced the tires on my fifth wheel five years ago (with Good Year Marathons) after I had the original tires blow. I have heard that after five years they should be replaced regardless of what they look like. My trailer gets used most weekends from May until October.
Trailer tires should be inspected after five years and replaced after seven. Trailer tires do not rotate for about six months each year and as a result, the sidewalls are not flexing. The natural oils in the tires do not migrate to the surface and the tires dry out causing sidewall cracks. There is a DOT code molded into the sidewall of each tire when they are built that can tell you the date when the tire was manufactured. The important part of this code is the last four numbers. If the numbers show 4207 that means the tire was manufactured in the 42nd week of 2007. Trailer tires are only certified for a top speed of 65 mph.