trunk pops open about 1/4 inch in reverse
 

when in reverse the trunk pops open about 1/4 inch when the
backup assists start up. sometimes the retractable also comes out
but not always. Could it be the central locking pump located
under the back seat is confused? I disconnected the battery
trying to reboot the pump. No results. Also checked for leaks on
all vacuum lines at the pump. No leaks. Any help will be greatly
appreciated. 1993 300SD
:confused:

When in reverse try keeping your speed below 100 mph.

I had the same problem it was a vac leak in the closing element.
they replaced handle and element problem solved.

popping trunk
 

rdanz: I previously had a leak in the vacuum pod which operates
the retractable trunk handle and consequently replaced it. it was
about 3months ago. This is new.