Door unexpectedly opens

[Testie]

W107 1974 with the hardtop off and on certain types of road conditions the passengers door popped open to first catch. Has anyone experienced this and is there a adjustment required or more sinister under pinning? My wife thinks I have set a trap for her but the door does not fully open only to first catch.
Col

[pastelgrey300D]

I've had this problem before and it was the return spring on the door handle - i.e. the interior pull handle wasn't fully springing back to the closed position.

Another thing could be that the lock striker is broken, they have a small piece of protruding nylon/rubber that the striker makes contact with - when this breaks off you really have to slam the door hard to get it to close properly.

Here's an image I found from elsewhere on the forum:

[Testie]

Thanks Dave I will check both of you solutions offered.
Col

[pastelgrey300D]

Hopefully it may be just the striker but you may have to remove the door trim and take the lock out just so you can lubricate everything - ancient grease plus years of dirt could be causing things to stick and not fully return.