If you still have the original you might be able to fix it. It's fairly easy to bend the tabs and open the cover.

I just got done with mine. Usually the windings are ok and the wiper arm is the problem. In my case the connection point had corroded and the arm fell off. If this is the case, it's quite easy to clean it up and solder it back on.

If the windings are damaged (open) it's probably not worth trying to fix it.

I really wish I had taken some pics, unfortunately I was in such a hurry to get it working, I didn't.