Apparatus including a downwardly-extending breaker bar connected for vertical movement by linkage to a base adapted to be mounted on a suitable traction unit. A hydraulic cylinder unit extends between the base and the breaker bar, and operating means is associated with the cylinder unit for selectively supplying fluid to said unit alternatively to raise and lower the breaker bar to cause it to strike a surface to be broken, such as the crust that forms on aluminum smelt in pots during the electrolytic production of aluminum.