1) Remove rear seat bottom (press in two metal tabs in foot well)
2) Locate and loosen 2 (1 per side) 10mm (IIRC) nits from studs that hold the seat back in place.
3) Pull seat back towards the front of the car, enough to clear thoes studs
4) With your hand, hit (upwards) the bottom of the seat back frame to pop the top of the seat back free of the the retaining device holding the seat back in place.
5) Slide the parcel/hat shelf out towards the front of the car.

That is how its done on the 107 SL-C, it should be the same on the W116.

__________________
". . .back before accountants designed cars"

-Current Stable-
'78 MB 450SL-C 107.024.12.020783 #3840 <Kayleen>
'85 FORD F250 6.9L Diesel <Allison>
'98 Lexus ES300 <Rachel>
Long Gone...
'74 Chevy G10...........................'99 GMC Yukon 4X4
'83 Chevy Suburban 6.2 diesel .....'99 SAAB 9-5
'90 Mitsubishi Eclipse GS............. '01 Chevy Tahoe
'98 Nissan Altima .......................'02 MB ML320
'88 Chevy Suburban V2500 4X4 6.2 diesel