Door keeps coming open!

[Frank E Bouy]

Does anyone have any ideas as to why my Vitesse driver's door should suddenly decide to open while I'm driving along. Somewhat alarmingly it does this on sharpish left hand bends, like pulling off a roundabout. Occasionally, I hear a light "click" and I know that it's unlatched so I'm ready for it. It shuts well enough and seems solid, then sometimes changes it mind while once we're moving!

[johny]

sounds very much like the car chassis is flexing which causes the door gap to open up effectively pulling apart the door catch and latch plate. Its most common on convertibles which is why they came with additional 'anti-burst' catches but can happen on saloons if rust has weakened the structure. Obviously the smaller the door gap is adjusted the less likely it is to happen.... 

[Pete Lewis]

Remind us   a converrible ?  These have a tongue on the door and a staple on the b post  salooms dont have these as std.

This  helps body flex 

First thing to check is the striker plate tight on the b post ?

Is the taper wedge underside of  the striker free and slides with a sprung return , this little gadget stops  the door lifting and  opening

There must be 3mm free play between the  release button  and the internal lock lever this is  adjustable

Pete