Mercedes-Benz M-Class 2012 Owners Manual - Manual (Page 217)

Hole in the ball coupling and ball coupling recess
X Insert the ball coupling horizontally into ball
coupling recess ? in the direction of the
arrow, until the hole in ball coupling A and
the hole in ball coupling recess B align.
Bolt
X Slide bolt C all the way into the hole in the
ball coupling recess and the ball coupling.
Bolt and spring cotter
X Secure the bolt using spring cotter D.
Correctly installed and secured ball coupling
X
Check the ball coupling, bolt and spring
cotter for correct installation.
G WARNING
If the ball coupling is not correctly installed
and secured, the ball coupling and the trailer
could come loose. As a result, you could
cause an accident.
Therefore, please observe the following:
R Make sure that the ball coupling is secured
with the bolt supplied and the
corresponding spring cotter.
R If the ball coupling cannot be correctly
mounted, remove the ball coupling. Under
these circumstances, the ball coupling
must not be used for trailer towing.
Have the entire trailer tow hitch checked at a
qualified specialist workshop.
Coupling up a trailer
G WARNING
Vehicles with air suspension program: While
you are coupling or decoupling a trailer, make
sure nobody locks or unlocks the vehicle and/
or opens or closes doors or the tailgate.
The vehicle's level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
switch or the vehicle level control system
when coupling/decoupling the trailer.
Trailer towing
215
Driving
and
parking
Z