Mercedes-Benz 2013 M Class - Manual (Page 258)

X Pull protective cap : in the direction of the
arrow, out of the ball coupling recess.
X Place protective cap : in the ball coupling
recess.
Ball coupling recess
Holes 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 holes in ball coupling = are
in line with the holes in ball coupling
recess ?.
Bolt
X Slide bolt A into the hole in the ball
coupling recess and the ball coupling to the
stop.
Bolt and spring cotter
X Secure the bolt using spring cotter B.
Correctly installed and secured ball coupling
X Check the ball coupling, bolt and spring
cotter for correct installation.
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.
If the ball coupling cannot be locked and the
key cannot be removed, remove the ball
coupling and clean it. If the ball coupling can
still not be installed (locked) after it has been
cleaned, remove the ball coupling. The trailer
tow hitch must then not be used to tow a
trailer, as safe operation cannot be
guaranteed.
Have the entire trailer tow hitch checked at a
qualified specialist workshop.
256
Towing a trailer
Driving and parking