Pic Request: Rear Seat Belt Retractor Mount

E28 technical advice asked and given! Troubleshooting, modifications and more.
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MrZ
Posts: 94
Joined: Nov 01, 2013 12:21 PM
Location: Walnut Creek, CA

Pic Request: Rear Seat Belt Retractor Mount

Post by MrZ »

Hi All,

I have a bit of an odd request. I'm retrofitting shoulder harness style seat belts to the rear of my E12 ('75 530i) and am looking for the factory method of mounting the retractor (not the pivot point mount in the middle of the c-pillar, which I've located). I know approximately where the retractors mount, and the location is very likely the same as with E28s given that both cars share the same part number for the inner structure of the c-pillar and rear firewall.

With that said, I basically need a picture of the retractor mounting point itself, which I expect is some sort of nut welded to the c-pillar inner structure. I'm not seeing such a mount on my car, and am just trying to get an idea of the best way to approach welding/reinforcing a mounting point.

Thanks,
Keith
taavipa
Posts: 52
Joined: Jul 19, 2017 6:42 AM
Location: Estonia

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by taavipa »

This should be the mounting point for the retractor.
Image

I'll grab you a close-up tomorrow or on the weekend.
MrZ
Posts: 94
Joined: Nov 01, 2013 12:21 PM
Location: Walnut Creek, CA

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by MrZ »

Awesome, thanks so much. A closeup would be super helpful.
MrZ
Posts: 94
Joined: Nov 01, 2013 12:21 PM
Location: Walnut Creek, CA

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by MrZ »

Would you also be able to take picture of your retractor? There are a ton of part numbers/styles floating around, so just trying to get an idea of what style mounts there.

Thanks
taavipa
Posts: 52
Joined: Jul 19, 2017 6:42 AM
Location: Estonia

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by taavipa »

taavipa wrote: Nov 19, 2020 7:31 AM I'll grab you a close-up tomorrow or on the weekend.
Or today
Image

Took a peek from the larger opening, the shape of the nut seems to be like this one:
Image
MrZ wrote: Nov 19, 2020 1:38 PM Would you also be able to take picture of your retractor? There are a ton of part numbers/styles floating around, so just trying to get an idea of what style mounts there.
Sure, but that would be tomorrow.
I think the retractor has a pin that mates up with the small hole next to the nut.
MrZ
Posts: 94
Joined: Nov 01, 2013 12:21 PM
Location: Walnut Creek, CA

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by MrZ »

Thanks!
taavipa
Posts: 52
Joined: Jul 19, 2017 6:42 AM
Location: Estonia

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by taavipa »

I actually have two different set of seat belts.

First set came out of an 83 euro chassis. Though, the date on the rear retractor is 01/85 so I guess they had been replaced before.
Part numbers 72111917772 (right), 72111917771 (left).

Note the plastic covered upper attachment tab
Image

Image

Note the 8mm pin.
Image

Only a single plastic pin to keep the covers on:
Image

If anyone wonders how the position-dependent lock works... I sure did.
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On the other side is the spring. It tries to jump off the moment you lift the cover, thus the clamp.
Image


The second set came from an 81 euro chassis. Retractor was built on week 48 of 1981.
Part numbers 72111883883 (left), 72111883884 (right).

No plastic cover on the top attachment tab
Image

Tri-wing screws on the end caps
Image

6mm pin
Image

Internals differ a bit too
Image


My buddy's 86 have different rear rectractors from these two but I wasn't able to get a good shot without removing the rear seats.

I don't see why you couldn't interchange these two. Unless some chassis have 6mm hole to mate the pin.
NB! The mating hole on the chassis is the one above the nut where there's a cut out in the sheet metal. So on the close-up photo it's to the right from the nut.

Between these two I fancy the older retractor. The end caps seem sturdier and it makes more distinguishable clicking sound when retracting (kinda cool).
MrZ
Posts: 94
Joined: Nov 01, 2013 12:21 PM
Location: Walnut Creek, CA

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by MrZ »

Very helpful!

So when mounted, how far does the pin actually go into the hole? Seems like not far given the step down from where the mounting nut is.
taavipa
Posts: 52
Joined: Jul 19, 2017 6:42 AM
Location: Estonia

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by taavipa »

MrZ wrote: Nov 21, 2020 4:12 PM So when mounted, how far does the pin actually go into the hole? Seems like not far given the step down from where the mounting nut is.
Only a few millimeters. I don't think it has any other purpose than to keep the retractor in the correct position so it wouldn't lock up. But that's just a guess.
MrZ
Posts: 94
Joined: Nov 01, 2013 12:21 PM
Location: Walnut Creek, CA

Re: Pic Request: Rear Seat Belt Retractor Mount

Post by MrZ »

Interestingly, the rear firewall is quite a bit more forward on my E12. I think I’ll be able to mount the retractor similarly though.
Image
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