w202 drivers seat slowly rolls back

[dikdik]

Whenever I adjust the seat to sit upright using that round thing at side of the seat, by journey's end the seat has leaned backwards again. What is causing this and how do I fix this its annoying me

 

[Grey Area]

This happened on my dads old e300, iirc it's just a ratchety bit that wears out after time and slowly lets the seat drop back. Annoyingly I think it only does it at a certain point, if you wind it forward far enough it shouldn't fall back again. Not that this helps if it's uncomfortable. No, idea how the insides of the seat actually function, but it should be possible to source another seat from a breakers.