Tail light leaks?

[rwnash]

I have been trying to locate the source of two leaks on my 1986 25 foot center bath trailer. The floor under the heads of both beds shows some water damage; last year after a period of heavy rain both mattresses' was damp. I can't see any obvious source, caulking seems to be in good condition. However, it is curious that the area of dampness on both sides was directly below the tail light clusters.

Has anyone had a similar leak related to tail lights and how did you fix it?

Thanks,

Whit Nash

[CRH]

To test the tail lights, get some painters masking film with blue tape on the edge. Cover the tail lights and spray entire rear with a hose. Better yet, put a sprinkler on it for an extended period. I would spray from the end cap top all the way down.

[GMFL]

What about upper rear clearance/marker lights. That could also be a prime location.

[CRH]

I agree on the marker lights. Mine had nothing but a thin gasket and no sealer. I have pulled mine off and sealed the wire and screw holes as part of PM.

[Airtandem]

check ALL exterior rivets and seams. Pull the shroud from Fantastic fan and feel the insulation for dampness. Remember, water also runs downhill. I had a leak and ended up being a cracked base on the fantastic fan. The water ran between the skins and came out at an interior seam.
I ended up replacing the Fantastics and painting the whole roof with BusKote



mj

[rwnash]

Thanks everyone for all the advice.

It finally is warming up in Michigan and I made a closer inspection of the roof yesterday. The caulk is not in as good condition as I thought and in several places the aluminum panels are not tight. (This might be a manufacturing defect; the rivets hold the panel together but not at the edge an inch away. Basic problem of making a once flat panel into a partial sphere I suspect.) I also looked at the upper clearance lights, they may also need some attention.

I'll pull it out of the garage in the next few days using sunlight for a closer look. I expect that I'll be using EternaClean and the various sealers and processes described in the thread on caulking. I have owned this trailer for about 10 years and never noticed any problem until the heavy rains late last fall - but that may be because it is always garaged except for 3 - 4 weeks a year which are (hopefully) good weather.

I'll report back when I'm done - and after an "artificial" rain test.

Thanks again for the good ideas.

Whit Nash

[blickcd]

Been there and fixed it. Also leaking was the vertical seam just inboard of the tail lights and below the window.

Had to be sealed from the inside, meaning drilling pop rivets and removing a section of wall skin in the corner. Since the head of my full sized bed faces the street side, I didn't have to remove the bed. Also when the wall skin was off I could see if water was coming down from up higher, such as the clearance lights or the roof vent, which it wasn't.

One final note, I could not get this leak to show up with a garden hose or sprinkler, or temporarily taping things off, and believe me I tried. Opening up the wall and waiting for it to rain was the only way.

Note my email signature...

[rwnash]

Christopher,

Thanks for the insight, not exactly "good news." Removing interior panels sounds challenging.

Project is behind schedule, doing internal repairs including replacing all the old polybutalyene(?) plumbing with PEX. (Water on the outside getting in and water on the inside of the pipes getting out. Fun.)

I did check one of the tail light lenses. Where it meets the gasket it was not flat and probably would not seal with the screws tightened. (On the other hand, when I replaced a backup light last year there was some water trapped inside.) While the "Monarch 425" lenses are apparently still available the gaskets are not. I still have not decided if I'll try to make new gaskets or try a different approach.

Good weather here today, I'll pull it out and start working on the seams. Hope to report back later with results and pictures of the tail light solution.

Thanks again,

Whit Nash

[blickcd]

My experience on the tail light lenses is that the gaskets aren't all that important, since the housing for the three tail lights only has an opening to the interior mid way up on one side. That is unless that housing has a crack in it on the bottom some place.

My tail light leaks were where the flange of the housing was sealed to the aluminum skin on the inside. Also, the screws for the lenses at the outer most corners protrude inside the wall cavity. You can put a dab of silicone (probably the only time that stuff is good on an Airstream) on those screws before you put them in.

You will want to check that housing from the outside for cracks, and try the silicone on the screws trick before pulling the wall skin off, especially since it would mean removing beds.