221Driving and o perationO pen coupling ball b ar. Remove key andput on provided protectiv e clip.When the coupling b all bar is locked theturn knob can no longer b e pulled out.Imp or tantCheck that the coupling ball bar is correctlyinstalled:z Red mark ing on turn knob p ointstowards white marking on coupling ballbar.z No gap between turn k nob and couplingball b ar.z C oupling ba ll bar must be seated firm lyin coupling housing.z C oupling ba ll bar must be locked andkey m ust be rem oved.Eye for b reak-aw ay st opping c ableIn the case of carava ns/trailers with brake,attach the break-away stop ping cable tothe eye. Ey e - see Fig. 17721 J.Dismounti ng the coupling b all b arC lose coup ling ball bar.Pull the turn knob out and then turn itclockw ise as far as it will go. Pull thecoupling ball b ar downwards out of thecoupling housing and stow it in theluggage compa rtm ent – see p age 219,Fig. 17729 J.Insert the sealing plug in the hole for thecoupling ball b ar. Fold away the socket –see page 219, Fig. 17717 J .Do not use steam -jet cleaners or otherhigh-pressure clea ners to clean thecoupling ball b ar.9 WarningTowing is permitted only with a c orrectlyfitted towb ar. If the towbar cannot befitted correctly, contact a workshop.