Find sliding door lock mechanisms at home improvement stores such as The Home Depot and Lowe's. Sliding door mechanisms come in mortise lock, twist-in, sliding pin, step-on and key configurations. Finishes include zinc, chrome, bronze and black, among others. HomeDepot.com and Lowes.com sell most of these types, as of 2016.
FixingScreens.com features detailed instructions and videos for correctly sourcing the new sliding door lock, as well as the removal and replacement of the old mechanism. These instructions reference size and shape dimensions, mechanism type, configuration and installation procedures. Access these options by clicking the Glass Door Locks link in the Door Trouble section.