Camry wipers not wiping

I put a new wiper mechanism in my 02 Camry, and I think I left something out.
The wiper motor is in there swishing away and the wiper blades aren't moving. I removed the mechanism and found that the small arm that makes it all
rotate keeps loosening. It's a nut which I'm sure needs a spacer or something to keep it from unscrewing itself.
Can anyone help?
Thanks a heap
Jim in MA

Go to a Toyota dealer parts department and look at the Illustrated Parts Breakdown on their computer and see what you are missing.