Parkingbreak not sprungits up on w204
 

Hi, recently got a w204 and found a problem with the handbreak/parkingbreak.
as you know its a lever you push down to activate in the footwell and a handle to release to your left. When I release it the footwell lever doesnt spring up and I have to manuellt help it with my foot. Any idea what the problem mitt be? I suspect it might only be something that needs lubrication but in that case what and where?

thanks!