Abstract: A lock is provided which is adaptable to heavy equipment, such as truck tractors or earth-moving vehicles, for equipment security. The equipment lock includes an elongated shackle with a split ferrule bondingly associated at one end. The split ferrule is received by a casing in which the split ferrule is lockingly engaged by a slidable yoke member actuated both for locking and release by key operation through means of a cam assembly. An enlarged member is at the shackle second end. The heavy equipment lock may be made to be water-tight when locked. In one embodiment, the shackle is flexible and formed into an adjustable bight to secure vehicle wheels. In a second embodiment the shackle is a rigid, "L" shaped bar.