I am simulating a damper model. In the 6dof method, I have given mass and gravity as the input for force and have given spring constant. my piston is also moving.

but the problem is it goes down(-3cm in y-direction) and comes back to its initial position (0,0). after, it is not going upwards instead it goes downwards again(in real case, it should go upwards that is +3 cm in y-direction).

how can I solve this