The first step in preventive servicing of machinery requires detailed inspection at frequent intervals by the staff responsible for its use. This will anticipate the possibility of breakdowns, and will thus save not only the cost of repairing them, but also the losses due to the holding up of work. In the particular case of truck transported cranes and excavating machinery, it should be required that both before, during and after a working period a number of key mechanisms should be checked, in addition to carrying out standard general inspection and servicing, such as cleaning, oiling, and making sure that no undue wear is developing in any part of the machine. It must be emphasized that in spite of the monotonous nature of this task, it is absolutely essential to carry it out, if it is to be avoided that this type of equipment should lead to heavy expenses and serious breakdowns.