I have a very well constructed, large, metal sliding glass door that leads to our patio. It was installed in the 1960's. It began dragging a bit. Upon closer inspection I noticed that there is a very thin sheath or sheet of metal that is in full contact and overlays the threshold. We pulled this sheath away last year because it had a jagged edge. Now the door won't slide and it doesn't "roll" anymore. It is as if it went from 0 co-efficient of friction to trying to push a car with no wheels.

WHERE DOES ONE BUY THE PIECE THAT OVERLAYS THE THRESHOLD? HOW DO I ADDRESS THE ISSUE OF THE DOOR NOT ROLLING EASILY? MY SENSE IS THAT THE DOOR HAS MIGRATED DISTALLY. THE FRAME JUST SITS ON THE BARE METAL AND DOES NOT SLIDE ON IT. help!! YOU CAN BARELY SLIDE IT. I AM BIG AND STRONG AS WELL AND STILL FIND IT A CHALLENGE.

John Fain, February 2008

Most patio doors run on roller wheels that are fixed onto the bottom of the door frame - can't really comment on your installation but mostly these wheels are adjustable. Usually there is a hole near to these wheels that you can pass a screwdriver through, on the door end. If you can find the screw inside and turn it, the wheels will either rise or fall and allow the door to once more run on its track, as intended.

John, February 2008