[pajama01504]

1991 r129...set belt would not roll out.
I removed the roll/retractor, and cut away a portion of the plastic shield where the Bowden cable and wires enter.
There is a tiny mechanism (finger),that when held back, allows the roll to “unroll”.
This was out of position. I fiddled with it, and it started working again.
Either the Bowden cable or a solenoid actuator will hold back this finger.
Note that these have an explosive charge (pyrotechnic) as part of the SRS system.
(TRW BAM P1 0334) which will instantly retract the seatbelt in the case of a frontal collision.
PS: new seatbelt assembly cost is roundabout $500.

 

[Wheelr]

How I hope I never have that issue.
Wonder what that repair would cost at an indy and cannot even fathom at the stealership.
Clarity: Where is the "charge"?
I didn't doubt your comment so I did a little googling and figured I'd post what I found

https://www.mbusa.com/vcm/MB/DigitalAssets/pdfmb/serviceandparts/seatbelts_airbags.pdf

 

[pajama01504]

pyrotechnic charge circled in red.

 

[Wheelr]

Thx. Took me a few minutes to remember (re-realize) just how over-engineered (not necessarlly in a good way) these MB's were.
I don't believe the instanteous pop-up roll bar requires/uses pyro.

 

[pajama01504]

The issue is...when this malfunctions, the value of the car plummets....it has to be repaired in a safe manner.
As I know, the roll bar is 100% hydraulic.

 

[pajama01504]

Well, after extensive out of vehicle tests, the unit failed again with 1 use. 😤
I could defeat it, but would be unsafe, as the latch would never catch.
Found a used unit, reasonable price on eBay. Will have to strip the seat one more time. 🤯

 

[Wheelr]

Brutal. Major props for your determination and perserverance