There's the hex head bolt on the hinge itself that is supposed to adjust how far down it's allowed to go. I've got the same issue and have yet to get around to it.
The rubber bumpers are supposed to twist and adjust how far down the bottom is allowed to go. There's a spring in the release mechanism as well, I would check if its lubed at all.
The rubber bumpers are supposed to twist and adjust how far down the bottom is allowed to go. There's a spring in the release mechanism as well, I would check if its lubed at all.