It's a rubber seal so don't use Vaseline. Use red rubber grease or silicone grease.
Sorry, but I've already used the Vaseline. It's fine with rubber. If you can put it on a baby's bottom, it can't be harmful. I've been using Vaseline on car battery terminals and hose connections for years without issue.
Meanwhile, I used the hair dryer, but it wasn't powerful enough, so dug out my heat gun from the workshop. It has three heat setting, warm, quite warm and VERY warm ............. and that setting will strip paint! Suffice to say, I used the second setting, but maybe six inches away from the glass.
By doing it for a couple of minutes whilst playing it about on the glass, and then waiting five minutes before another application, the moisture has gone so I re-fitted the bulbs. The seal was in good condition though dirty, and after a good clean, it looks great.
I cleaned out the cover and applied a smooth layer of Vaseline under and over the seal, and fitted the seal in the opposite orientation so the top bit is now at the bottom. I would expect that the seals when new, are circular.
All done, and time will tell if there's a deeper problem.
The car was laid up for a few weeks outside before we took it on, so maybe lack of use has exacerbated the issue of a poor seal.
Fingers crossed,
Mick.
