My Garmin 205 is 2-3 years old, and I normally leave it attached to the windscreen, as safe in my neighborhood (Moo Bahn) to do so.

Sometimes I am driving along and it falls onto the dashboard, and other days I find it there in the morning. Other times stays attached for days.

Any suggestions, or do you know if I can obtain a new rubbers sucker mechanism?

Same problem, but off GPS topic:

I bought a Fujiko Dash-cam 2-4 years ago, and that too falls off the windscreen after and hour or so. The annoying bit is a difficult method of fitting (Remove from bracket, unscrew pressure ring, align position, screw pressure ring 3 times (do again if not aligned correctly) the reattach camera to bracket and set pitch.

While there unit was wonderful for touring Thailand and videoing small villages as you pass through for a travelogue (which I never did), it does 8 hours continual filming before over writing the first frame.

Try smearing a film of cooking oil on the suction cup. It'll stop the air being sucked back in.

I too had this problem with two different Garmin models. I solved it by buying a bean bag from Garmin, tossed the windscreen mounts, works a treat.

Eagle GPS has solutions;

http://www.eaglegps.co.th/index.php/lang-en/accessories/nuvi

I much prefer the bean bag friction mount.

I also had a problem with my Garmin windscreen mount. It was okay for about a year, and then one day I found it on the dash, the rubber had split. Tried to get another one over here, but everyone said they were only sold with the unit. Managed to get one off ebay. That one broke also. I tried the cheap after market ones, but they're useless.

I now use Blu-Tack.

The other problem I had with the suction mount was that where the sucker was mounted, it pulled my window tint off the windscreen.

Both my units came with a round self adhesive plastic disk. I hesitated about putting them on the dash but finally did on both the car and the truck. The suction cup works much better this way. A little Vaseline around the edge of the suction cup works wonders. I sold an old Garmin I had and the bean bag friction mount went with it. The bean bag is the best option.

Just wet the back of it. Not a problem in 4 years.