Passenger Side Wiper Not Tight to Windshield

Are both nuts tight that hold the passenger arm?

 

Have you removed it and visually confirmed where the worn out places are?

And yes, you're correct that this is very rare problem for Prius. First time I've read of it in 8 years on here...

And because your car is 14 years old there's no need to by a brand new one. Simply find a local wrecker where you pull the parts yourself and just remove the worn out bushing/parts you need. This will keep the cost of repair incredibly low.

 

BUT is there any play in the arm or shaft ?
Is the arm seated all the way down on the shaft before the nuts are tightened ?

If that is all OK, then there is a pivot and spring in the arm itself that might need some exercise and lube........or a new spring.

 

You showed real determination getting that plastic cover off. I did it once, to say I did, and then decided not to after that, as I found when those bearings do need lube it works well enough to squirt it in from the undersides.

I think if you felt a lot of actual play there, you might end up replacing the arm. There might have been an earlier point where lubing would have kept the play from developing, but 20/20 hindsight is the commonest kind.

 

Well... I think that pic explains what your problem is. Do you still have the cover?

Those two black nut caps that bolt the two arms to the car is what you're suppose to remove when you "take off" your wiper to work on it.

But in your picture the wiper was never taken off and the cover that is missing is NOT supposed to be removed like that, which is why it's all busted around where you're experience everything being loose. I guess you or someone before you damaged those pivot points by prying /damaging the cover and now those joints are failing due to being pryed at / exposed to the elements?

Maybe you can get by for a little while, but you need to get to the junk yard and buy a replacement... This is what your wiper part is supposed to look like:

 

I wonder if it was different on Gen 1 (the one I removed). It was 'easy' in principle, just a plastic cover with tabs to push back to release it, but the tabs were incredibly stiff.

 

This might not be abnormal.
On some vehicles, you can actually see the side play in the shaft while the wipers are running.

 

Pretty sure none of mine have had anything I would call "a ton of play".

I have had to lube those bearings, both in a Gen 1 and later in a Gen 3, when they got dried out to the point they were noticeably slowing down the wipe. (Easy way to check: lift the blades from the glass, turn on the wipers. If the cycle is still slow, it's probably those bearings. To be sure, remove that passenger arm. If the driver arm then cycles at normal speed, it's definitely those bearings.)

If the bearings were to get bad like that, and not get lubricated, but just continue to be used in that state, I could see that eventually progressing to a "ton of play" situation as they eat themselves up.

 

My inner 15 year old has been awakened......