Anyone else have a kind of waggly wiper arm if the screen isn't perfectly clean or if it's slightly dry? Mine seems to allow what i would consider extra play at the mount point.

 

I think all do this. A lack of lube causes it. My wife hates the sound on her journey and reminds me when i need to turn it off...

 

8 Year old windshield being sand blasted by road debris is the main cause. Replace the windshield and the wiper blades and they'll glide across the glass as new.

 

Lube? as in just how slick the surface is? or in the wiper assembly somewhere?

I'm lucky to have a brand new Ford windscreen on it, so it's not that.
I don't have this problem all the time, so long as the screen is sufficiently wet, it's fine, just seems that at it's extend of range, there is so much play in the arm shaft that it binds and well, waggles a bit.

 

Yes, how much rain is or isn't on the windshield surface

 

Yeah, it only seemed to do it when the screen wasn't fully wet, as i reversed out my driveway, just seemed odd and i wasn't sure if it was normal/broken/needed adjustment etc. Thanks, guess they all do it.

 

If your talking about the wiper chattering, I adjust the angle of the wiper by twisting the arm just enough to make it neutral or whatever the term is called.