Wiper motor rotation

Ok, I have a mid 90's GM wiper motor. I am using this for a halloween prop and need help on how exactly this thing works. I noticed that the shaft does not rotate a full 360 degree's, extremely minimal almost like a push rod of a steam engine wheel. At the base of the shaft is a flat disc which is rotating the full 360's degrees which is what I need..

I am not a gear head by all means so any help as to how I get the shaft to fully rotate is appricaited. If it does not or cannot, please let me know as well..

The only thing I can think of is having a piece of metal rod welded to the flat disc which rotates 360 degrees. Sorry If this is not clear, but this was the best way I could explain it. See picture below, hopefully that helps clear it up.


http://i916.photobucket.com/albums/ad2/steamer482/bedroom013-1.jpg

The internal gears and drive will not allow full rotation.

Thanks GM - that's the confirmaiton I needed!

Yes you are right the shaft will not rotate fully because the internal gears and drives will not allow it to rotate fully.