I followed the instructions as posted in the third post in this thread, I added the use of a brush.

No I didn't remove the belt but just pulled out the slack and clamped with a budget plastic wood clamp.

Kristophe did you do any cleaning of the retraction mechanism?

I wiped mine down with a mild APC and an MF towel over the weekend and allowed to dry and my drivers belt now retracts worse.

I'm gonna clamp it fully extended, use my steamer and some cleaner and a brush to get the grime out.

UPDATE:

Much better now. I clamped the seat belt out all the way and went over it for 2-3 mins with my Rowenta steamer (I used it to press my shirts in the house), did some deep steaming and just wiped down with MF towel. Seems to do the trick!

thanks for all the experimenting, RB. Definitely gotta try this on mine this weekend, stickin just a bit too.

I'll update again as they are drying overnight. But I pulled a ton of grime out on the towel (I wrapped the steamer head with the towel so the grime had something to absorb into). I also pre sprayed the belt with 1Z Deep Plastic Cleaner (non acidic, water based but a strong cleaner for fabrics and plastics)

No RB I didn't clean the retraction wheel/mechanism since post cleaned seemed to do the trick. I cleaned the belt with very hot water with some added Lysol cleaner and used a brush. I then rinsed and went over again with a rag and and some very mild bleach deluded warm water. Your steam method would certainly be ideal.

Common problem in many modern BMWs (after 1990s) as they use the same part supplier.

I wrote a detail analysis in my 1998 528i (E39) below:

DRIVER’S Seat Belt Replacement DIY - Bimmerfest - BMW Forums

After all these years analyzing it, the morale of the story is: live with it...lol.

The spring mechanism in this device is not strong enough, even from factory.

UPDATE:

Thanks cn90, that makes perfect sense to me. Definitely something I wish they wouldn't have screwed up, it is an annoyance. I noticed the hook on the B-pillar is mostly where the belt gets hung up (as per your pictures from BF), I may try some Teflon lubricant on the hook to help the belt roll smoother on it and create less friction.

This may be one of those times where a dry lubricant may actually help the belt slide in the "hook", because although my belt is now clean, it doesn't have the "slip" on the hook needed to feed into the retractor.

Would be nice if we could retrofit a different retractor mechanism and still keep our functional belts.