c) Maintaining an even pressure from the carrier to the hammer, start the hammer. If the
downward pressure from the boom is too weak, you will hear metallic (rather than
sharp) strokes, because the hammer is not striking the tool correctly. If the downward
pressure is excessive, it will produce strong vibrations in the carrier and the tool,
retaining axle, bushings, etc.
d) If the hammer is in the correct position, and the hammer and case are vibrating, the
downward pressure from the carrier is insufficient. If exerting further pressure from the
carrier does not solve the problem, it may be that internal hydraulic leaks from the rams
or valves may not be allowing the carrier to exert the correct amount of pressure. In
this case, replace the carrier cylinder seals and/or check the control valve seals.