Look carefully at the upper notch that the torsion spring will lock into...if this is cracked/bent/deformed, odds are the spring will not lock and stay in place and if it does stay in place your lid will sag due to the loss of tension...this upper positioning slot also helps align and keep the torsion spring parallel to the plate with the locking holes...damage here can also allow the spring to shift and not stay parallel to the plate, possibily jumping out of the locking holes. Look for bent or even cracked metal in the upper hanger..