Greetings Prius C owners~ Joined to find-EZ fix for loose black rubber seal (roof drivers side)

Congrats and welcome. I hadn't heard of this seal problem. Any chance you can share a photo that shows the problem?

 

If it's the rubber strip that runs in the drainage channel over the two doors on top of the car, I had the same problem. I believe its just a friction fit and can be pressed back in with your fingers. If that doesn't work, there may be clips on each end that need replacing. The only time I had issues with mine was after going through an automatic car wash. The brushes loosened it up. Pushing it back was all that was needed.

If that's not it, please explain further.

 

If it IS that rubber strip and fills the channel meant for mounting a rooftop luggage rack........
then you have two choices:

Get a new one from a dealer. Actually get both and replace both sides as they shrink with heat and age.

Or get some body emblem cement or silicone RTV and glue it back in place in a few spots down along
each edge.
It only snaps firmly into a clip at each end.

 

This was a problem on the drivers side of my daughter’s 2013, I put some butyl tape under the section that lifted up and she hasn’t had a problem since. I can’t post a link, but search Amazon for “zxmt butyl tape”. I used the stuff that looks like a black cord.

good luck