My driver's seatbelt buckle on my 2005 has become really loose. I thought the bolt had gotten loose but it's not, it's on tight. Looking at the parts diagram, there doesn't seem to be any spacers that would help tighten the buckle. Does anyone know if there should be another part to tighten that buckle? All I see is a bolt but it's still loose when the bolt is securely fastened. Something has to be missing..... here's the online parts diagram, part #8 is the buckle, #9 is the bolt. Nothing else. 2006 Toyota Prius Parts - Camelback Toyota Parts - Genuine OEM Parts - Free Shipping
I am not aware of another part. I suggest that you remove the driver's seat so that you can remove the seatbelt buckle. Once it is removed, if it is not obvious what the problem is, then remove the front passenger seat so you can compare the seatbelt buckles from both sides, thus making it possible to determine what is wrong with the driver side.
So that washer was missing at the driver's position? Can you get a suitable replacement from your local hardware store? Your OP states the seatbelt buckle "has become really loose" which implies that at an earlier point in time, the buckle was not loose. During your ownership of that car, was the buckle always loose?
I was vacuuming the car and I found the broken washer, it's a very thin piece of metal, not sure a hardware store would have this. Not sure how it broke off either, it's not suppose to be a real moving part, just tilts slightly for you to put on your seat belt. It was working properly until that washer broke
Better take that pic down to the dealership parts department. See if they can find the torque spec too, and if there's any thread lock (say Loctite) or whatever.