Had removed one of the taillight bulb sockets from the socket holder and removed the bulb. The bulb was lite when I took it out. When I replaced the bulb I had turned it 180 degrees and it lite up twice as bright as it was originally. Because of the two offset pins on the side of the bulb it will only go in one way, the least bright way. Why brighter one way than the other? Do I need new bulbs? Thanks.

It's a dual filament bulb. When you put it in correctly the tail light filament is lit. If you force it in the wrong way, the brighter brake light filament is lit. This is totally normal.