A lot of the older dump systems used plain old 30 weight non-detergent motor oil to power the cylinder, and as the piston rings and pumps wore, people would use heavier oil such as 90-weight gear oil to minimize leakage and increase the lifting capacity. This was not a particularly good idea!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!