During a seminar I presented, one of the attendees, a maintenance manager for a large open-cut mining operation, mentioned that he was considering upgrading the filtration on their fleet of hydraulic mining shovels – to achieve a higher level of hydraulic oil cleanliness.

There’s lots of documented evidence to suggest that increasing hydraulic oil cleanliness increases the service life of hydraulic components – all other things equal. Whether such an initiative would yield an acceptable return on the investment required for the machines in question, depends on a number of variables, which I don’t have room to go into here. But this got me thinking about a bigger issue.… continue reading »

Here’s the scene for an unusual but instructive hydraulic troubleshooting story:

The end of the month was just a few days away when an OEM customer called and advised its hydraulic cylinder manufacturer that the boom extension cylinder on a rough terrain forklift was SQUEALING. This single-stage cylinder was 6″ bore x 3″ rod x 14′ stroke. The OEM was in a terrible position because they had 80 machines that could not ship by the end of the month deadline due to the squealing – which could be heard blocks away. The OEM was demanding that the cylinder manufacturer send a crew of men to change out all 80 cylinders!… continue reading »

I am regularly involved in troubleshooting problems with hydraulic equipment. In these situations, there are two things I always do before reaching for my test gear. The first is to conduct a visual inspection of the hydraulic system, checking all the easy things that could cause the problem in question (never overlook the obvious). The second is to ask for the schematic diagram for the machine’s hydraulic circuit.

A schematic diagram is a ‘road map’ of the hydraulic system. And to a technician skilled in reading and interpreting hydraulic symbols, it is a valuable aid in identifying possible causes of a problem.… continue reading »