And why the pump is often not the problem This is one of the most common calls we get. The machine has gone slow, the operator is complaining, and somebody has already decided it needs a pump. Sometimes it does. Often it doesn’t. A main pump is one of the most expensive components on an excavator, and replacing one that was never faulty is an expensive way to find out the problem was somewhere else. Worse, if the real cause is contamination or a starved suction line, the new