An apparatus for limiting the travel of a slave piston (110) in a slave piston cylinder (100) in a compression release engine brake is disclosed. The apparatus provides stroke-limiting means and independent lash adjustment means which may be installed in a common rail, variable valve actuation system. The independent lash adjustment means comprises a sleeve (300) around the slave piston (110), threadably mounted in the brake housing (40). The stroke-limiting means comprises a slave piston (110) in a slave piston cylinder (100), a trigger valve (90) and a hydraulic circuit connected thereto. The slave piston stroke is limited when a lower flow port (130) in the slave piston cylinder (100) is opened to drain (81) slightly before high-pressure flow is cut off through an upper flow port (120) in the slave piston cylinder (100).