camperdave mentioned leaking clearance lights in another thread. Thanks to that tip, I was able to locate a mystery leak in our C at the back. I was running out of Eternabond sealing everything above there to no avail. Gottaluv this forum for good tips! Thanks. :)

One of the first things I did when I took possession of our RV is to caulk the top and sides of all of the clearance lights. That stopped the leaks but now all of the caulk is an ugly black and won't clean off. I wonder what paint would stick?

You should be able to seal the lights without any sealant being visible. Remove the lights and seal under them. Wipe away any excess that squeezes out.

A tip from my boating days... When you are attempting to seal anything keep in mind that the caulk product is there to form a gasket not to glue things down. You should apply the caulk and lightly tighten the screws/bolts etc., and then let it cure for 24 hours. Then after it has cured tighten everything down. If you apply and then tighten you merely squeeze the caulk out from where it needs to be.By waiting until the new "gasket" has cured before torquing down the fasteners you get a long-lasting watertight seal.:C

Many class C units have phanthom leaks that the owners go nuts looking for and it turns out to be either loose clearence units or bad caulking or cracked lenses or improperly installed new lenses, I had one instance of a leak and remembered that we had a bird strike the day before, climbed to check and did not notice anything wrong until I started phisically trying to wiggle the units and found the center one cracked and that allowed water to get inside the unit and throug the cable hole, used awning tape as a stop gap until I replaced all the marquer lights with new ones a few days latter, so do check those lights they also deteriorate with the sunlight and time.navegator

Clearance Lights Leaking -Thank you For the Tip.

BruceMc
Explorer III
Dec 19, 2018
Their seals leave a lot to be desired, but at least the newer styles are using a foam seal instead of butyl tape & caulking...

The problem is the assembly. I got to looking at one of my rear clearance lamps, and discovered:

(look closely at the bottom edge)

(keep looking....)

And this is how it wasn't sealed:

And I'd been spraying water up that direction for 2 1/2 years... fortunately the wiring feeds into a horizontal aluminum square-wall framing member. Who knows how much water migrated in, but so far I've never seen any damage as a result.
chuckbear
Explorer
Dec 15, 2018
Stop using caulk. I sealed all of mine with a good quality butyl take and trimmed off the excess. Can't see it and no leaks in over 2 years. Chuck
T18skyguy
Explorer
Dec 14, 2018
SidecarFlip wrote:
Easiest solution to leaking clearance lights I know of is replace them all with sealed LED lights.

This is a great idea. With the bulb type lights, their so close to the plastic, that the heat breaks down the plastic and it cracks. I bought new aftermarket LED cab lights that are much higher quality.
Oasisbob
Explorer
Dec 14, 2018
Why O why do the lite mfg,s not include a rubber seal? Too cheap I guess. We all know this is a leak point.
Chrisatthebeach
Explorer
Dec 14, 2018
I have always removed them, put plumber's putty on the back and replaced, tighten down and clear off the excess, same as setting a sink strainer.

Never had a leak afterward.

If the kitchen sink in a home can go decades without the putty failing it stands to reason works as well on a clearance light. The kitchen gets multiple daily cycles of hot soapy water through it and holds up quite well.
ItsyRV
Explorer
Dec 14, 2018
SidecarFlip wrote:
Easiest solution to leaking clearance lights I know of is replace them all with sealed LED lights.

As mentioned, clearance lights can have water leaks from two sources, external and internal. Replacing them with sealed LEDs only solves the internal leaks. The sealed LED still has to be mounted and wired to the RV and it's through those penetration points, water can enter the RV through a failed seal.
Harvey51
Explorer
Dec 14, 2018
Great topic, thanks to all. I started to replace my clearance lights with LED ones last summer after one got cracked but only did two of them. The tips on caulking are very much appreciated.
pnichols
Explorer II
Dec 14, 2018
SidecarFlip wrote:
Easiest solution to leaking clearance lights I know of is replace them all with sealed LED lights.

You still have to somehow seal the sealed light against the maybe slightly flexible non-metal surface with a hole in it that is behind each light so as to never leak in the worst case scenario of driving into highway speed wind in maybe pouring wind-blown rain.

My clearance lights no longer work - but are still there - because I years ago covered each light's hole in their fiberglass mounting surface with a round piece of Eternabond.
SidecarFlip
Explorer III
Dec 14, 2018
Easiest solution to leaking clearance lights I know of is replace them all with sealed LED lights.
navegator
Explorer
Dec 14, 2018
Many class C units have phanthom leaks that the owners go nuts looking for and it turns out to be either loose clearence units or bad caulking or cracked lenses or improperly installed new lenses, I had one instance of a leak and remembered that we had a bird strike the day before, climbed to check and did not notice anything wrong until I started phisically trying to wiggle the units and found the center one cracked and that allowed water to get inside the unit and throug the cable hole, used awning tape as a stop gap until I replaced all the marquer lights with new ones a few days latter, so do check those lights they also deteriorate with the sunlight and time.

navegator