If I park with my 451 in the garden, the doors will not remain open because I live on a mountain. So depending on how I park, at least because of the slope, a door will not remain open by itself. Will the door arresters become weaker over time or would that be the case with new detectors? Is it possible to increase the holding force of the detector somehow? Sometimes I clamp a piece of firewood in order to keep the door open when I have to do something in the footroom, but that’s annoying.