Stanek Hi Impact sliding glass door
A handy person from Florida--formally N.J. says:
September 5, 2016
Roller adjustment "just spins", door has dropped, side adjustment-tandem roller, Stanek series 4000 patio door, MST 12080, 47 3/8" slider No photo available since I would have to remove slider to get at it.
Tom from SWISCO responded:
September 6, 2016
It sounds like you need a new roller. Unfortunately, I'm not familiar with that brand, so I'm not sure what to recommend. I'm afraid we will need to see a picture of the complete roller out of the door in order to identify a match.