Should I leave well enough alone

The best place to inspect those four long screws is from the inside ceiling side. Just pull down the filter and you can see the four long screws mentioned above. They are suppose to be tight enough to depress the 14-inch square gasket about 1/4-inch. You will notice right away if they are loose. This is the only thing that holds the top unit together with the bottom unit.

This is neat simplified diagram of a roof mounted Air Conditioner unit


Roy Ken