...on the driver's side=left, right side is fine. Is this a known issue, any ideas before I start to take apart?

 

No Quarter
I think as all cars get older and seat belt is used more (especially the driver’s side), the belt itself gets dirty. This essentially adds to the thickness of the many webbing wraps on the retractor and causes the retraction to be balky. Many YouTube videos on this.
Happened in my wife’s 2004 Toyota Avalon so I cleaned it thoroughly. Pulled the webbing all the way out to expose as much of it as possible. I used a paper binder clip as a clamp to keep the webbing from retracting. Scrub the belt well with a mild detergent and a small soft brush. You don’t want to abrade the webbing for aesthetics. Let it dry thoroughly. A fan helps with the drying.
I also accessed the retraction mechanism too and cleaned lots of dust, lint, and pet hair out of it🐶
Retraction works much better and wife is happy which is the ultimate proof!
Mike

 

Mike, awesome reply! Out of curiosity, how did you access the retraction mechanism? Easy or difficult?
Thanks!

 

Marc
My effort was on an old Avalon sedan so just had to remove the bolt holding the retractor to the car frame and a couple interior trim pieces. Pretty easy.
I looked at the X150 manual recently to see how the rear audio speaker gets accessed. As I recall, part of that effort required removing the front seat belt mechanism in order to remove the rear seat side trim behind which the speaker resides. Didn’t look too bad a job but I would try just pulling the belt out as far as you can and cleaning it first. Manual said to install a new seat belt anchor bolt if you remove it.
My Jag doesn’t get the dirt and abuse the Avalon does and no one can ride in the back so I would think the mechanism would generally stay cleaner. The belt is much more prone to getting dirty.

 

I've had this on previous cars, I use silicone spray lubricant which seems to work very well. Sit in the seat and put the seatbelt on, put paper masking tape around the belt just beyond the point where it makes contact with your shoulder. Spray a cloth liberally with silicone spray. Pull the seat belt all the way out and rub the cloth back and forth along it until you reach the masking tape. Pull it right out again and back in. Repeat the spray step if necessary.

 

Marc, you will need to pull the inner quarter panel to get at the retractor.