I have a 2007 S40 T5. I was changing the rear brakes last night and decided to give the rotors a spin while the calipers were off. I noticed a clicking sound coming from the wheel hub. My instinct is to say "wheel bearings are worn" but don't want to jump to conclusions. I was wondering if anyone knows of any sensors or mechanisms in the wheel that might be giving me this clicking noise. Thanks!

 

I wouldn't worry until it progresses to a grinding you can hear in the cabin. If it's really a bad bearing then you won't have to wait long.