Using the measurements given to fix the lid at a 90 degree angle did not help. I have about 82 degrees. I checked and rechecked the mounting dimensions/directions and even tried moving the mount a bit to keep it at a 90 degree angle. At this point, the ram did not fully close. That confusion aside, I think this is a good buy. I have used a shock absorber on a 10lb toy chest and it works great. The ends of the bracket are plastic, and everything else is steel or aluminum.