Sliding Patio Door hard to open, easy to close
We have metal-frame patio doors 6' wide, built in 1980 and original doors. The back patio door has been sticking at the bottom (at the outer side away from the lock) when pulling open. It closes fine.
I sprayed it last year around the wheel down there with some silicone lubricant and it seemed to help a bit but it's still stiff.