Today, I’m going to switch gears and talk about us versus them. Them being the guys who make hydraulic equipment and us – well we’re the guys who have to keep it running.

Consider this situation sent to me by one of our members:

“We operate 40 sugar cane harvesters working about 3000 hrs per year. Each of these machines has over 20 gerotor/geroller hydraulic motors driving various components.”

“In recent years one of the manufacturers has eliminated the case drains and added a high-pressure shaft seal. This tidies up the hoses but the high-pressure seal grooves the shaft causing leaks.”

“Because of the number of motors in the fleet we spend a great deal of time resealing or repairing the lower end of these units.” For those not familiar, with this type of motor a case drain is not compulsory (unlike a piston motor). If a case drain isn’t fitted, a high-pressure shaft seal is installed, along with (usually) two check valves that connect the seal cavity to the return side of the motor. This changes with motor direction – hence the two checks. But as you can see, eliminating the case drains on these harvesters has resulted in an ongoing maintenance headache for the end-user.

So why did the machine manufacturer do it? Unfortunately, most hydraulic equipment is built to a price and not a standard. This manufacturer obviously thought it was a good idea to fit case drains to these motors in the beginning – the motor manufacturer likely advised them to do so. As time worn on someone in the design office probably figured out they’d save a couple of hundred boxes per machine on their build costs if they eliminated this case drains.

Boy, is the machine owner paying for it now. But it’s not all the manufacturers’ fault. They build machinery to a price – because end-users buy largely on (ticket) price. Until end-users wise up, get more knowledgeable about the equipment they depend on, and base their buying decisions on life-of-ownership cost, this win/lose game will continue. Yours for better hydraulics knowledge.

Brendan Casey