My front seatbelts are getting very slack i.e. not reeling back in properly. Do I need to replace the entire unit or can I just replace the reel at the bottom ?

you dont need to replace any thing.this is a common fault.the reel at the bottom needs cleaning & oiling.

So remove the panel, oil and clean the reel - How do I remove the panel ? Is it easy or fiddly ?

the belts in the reels may be getting a bit damp due to any water ingress you could be having ,poss inner door panel seals , the belt will swell up very slightly making it slower to retract

i took mine to the dealers to tell them,

got told it was £160 fora new seatbelt and the "slow" one was tested once replaced and if not found to be faulty i'd be liable for the charge.

asked what i could do instead

"pull all the way out wipe and spray with silicon spray"

Pull the belt out, spray the inside lighty with silicone lubricant

"Spray the inside" - please elaborate - do you mean spray the belt itself, remove panel and spray the reel or simply spray from above without removing the panel ?

Generic silicone lubricant or WD40 ?

not WD40 , silicon spray is used to lubricate door seals and other rubber type seals , you should be able to get it from a good motor factors

From a TSB -

If a defective function of the safety belt is found, (the belt is not rolling up, it is rolling up too slowly, it does not roll up entirely), first, a thorough visual and functional check, according to following procedure, must be carried out:

1. The defective safety belt strap must be completely unwound from the reel of the rolling up mechanism and if the belt:

a) is not rolling up entirely

I've just had the passenger side front seat belt on SWMBOs Furby replaced under warranty for just this problem.

We also had the drivers side belt on the company Passat at work changed. This was under warranty too.

My driver's side one is a little slack, and I think its to do with the 180 degree fitting that sends the belt down in behind the panel. I can pull the belt out below this fitting and it goes back quite fast. It seems almost as if the belt has increased in thickness and is simply struggling to go through the loop. I might give this silicone stuff a go, but for now I'm happy to either wait a bit, or do I what I usually do, and just help it along by pulling it through from below the loop.

It is amazing that this is required these days, I've got the same problem and it seems it's probably the 'eye' at the top that's dirty on mine.

I've never had to 'maintain' my seatbelt, ever, on ANY car I've owned. I've had to replace a seatbelt in a very old Fiesta that had >140k on the clock but that car was old and you'd expect something like that, there was minor damage on the belt but the rest was fine.

spray the belt itself

spray the belt itself

I'd advise that you're careful what you use - don't want to end up using a chemical which may weaken the belt.

My driver's side one is a little slack, and I think its to do with the 180 degree fitting that sends the belt down in behind the panel. I can pull the belt out below this fitting and it goes back quite fast. It seems almost as if the belt has increased in thickness and is simply struggling to go through the loop. I might give this silicone stuff a go, but for now I'm happy to either wait a bit, or do I what I usually do, and just help it along by pulling it through from below the loop.

Exactly the same's happened on mine. A good clean of the fitting has helped considerably...

Thanks for all the replies. Now that I have examined the problem more closely, it does look like it's the loop above which is causing the incomplete reeling in. So I will try a bit of cleaning and maybe a bit of silicone spray.