Abstract: A retractable caster assembly incorporating a strut lock formed of a sleeve mounted on the strut for sliding movement thereon, between closed position removed from the pivot axis and not interfering with the folding of the strut, and operative position seated over the pivot axis to hold the strut members in aligned, operative position and prevent their pivoting with respect to each other. Sleeve control means are mechanically associated with the sleeve automatically to move the sleeve to closed position when the wheel is being retracted and to operative position when the wheel is moved to operative position.