Abstract: An improved parking brake is provided for use on a movable machine, in particular a lift truck with an elevating platform. A pin-type brake is provided with a buffered slide mechanism which engages and disengages a slotted disc mounted on a wheel to brake the machine while not in use. The buffered slide mechanism provides a delay for the slide mechanism when the slide and apertures in the slotted disc are not in precise alignment, and automatically engages or disengages the brake when the slide and disc apertures are in alignment. The brake also reduces wear on the internal cylinder components by providing a slide supported at its ends by guides and pivotally linked to the cylinder mechanism.