LS3a Airbrake question

I have a problem with my LS3a. During flight, from 90 km/h, on both
wings the airbrakes comming out from the wings slightly (some
millimeters), a little bit higher during ircling flight, during pull-
up and at higher g-loads.
Yesterday I have tried the following during flight:
I have pulled the airbrake handle very slowly back from closed and
locked position untill to the point that I felt resistance and looked
the airbrake covercaps on the wings.
It was interesting that fulling back the airbrake handle 5-I0 mm the
airbrake covercaps went back on both wings to their good positionthe.
I think it means that the over-center (self-closing) is not correct.
Does it mean that the ocer-center is incorrect ? Is there any way to
set the over-center ?