Why won't my wheeled vehicle move?

Hi, I have not read all of comments on this page, but in case you are still looking for a workaround to fix it - just read this thread, it offers, very likely, what you need:

https://forums.unrealengine.com/development-discussion/content-creation/21359-collision-problem-on-vehicle-model-skeleton-importing-from-maya

Make sure to read till end (2 pages), it helped for some people, (if not for everyone)

Edit:

That video is somewhat outdated, make sure to check these official doc guides as well:

(Optional) If you are new, then read look at “Physics Asset” section there:
http://api.unrealengine.com/latest/INT/Engine/Physics/Vehicles/VehcileContentCreation/index.html

(Important) up-to date vehicle setup guide: