Mercedes-Benz 2009 M-Class Operator's Manual page 214

Controls in detail
Loading and storing
Release handle
3
Seat backrest
4
X
Make sure the rear seat head restraints are
Y
in the lowermost position (
X
Pull release handle 3.
212
A red indicator
backrest is released.
4
Indicator
5
page 100).
X
Fold seat backrest
will be visible and seat
5
forward.
4
Returning rear seat backrest to original
position
Seat backrest
1
Seat cushion
2
X
Fold seat backrest rearward until it
1
engages.
Red indicator ( Y page 212) should no
5
longer be visible.
X
Fold seat cushion rearward until it locks
2
into position.
X
Check for secure locking by pushing and
pulling on seat backrest 1.