July 12, 2022 News

In the last hydraulics bulletin, I challenged you about how well you know your hydraulic equipment. Today I’m going to explain an often-overlooked problem that can quietly destroy a hydrostatic transmission. But first, a short background story:

Rupert Murdoch, the boss of global media giant News Corporation was a neighbor of ours where I grew up. Not that my family was particularly well off. It’s just that my father’s farm happened to be situated close to a group of “sheep stations” the media mogul owned. Compared to the 300,000 acres Murdoch controlled, Dad’s landholding was modest indeed.

In 1981, just in time for the wheat harvest, Dad took delivery of a new combine harvester. It was one of many he owned over the years, but this one was different. It was the first I’d seen equipped with a hydrostatic transmission for the ground drive. The infinitely variable and stepless control afforded by a hydrostatic transmission was quite an advance over the mechanical gearbox with a variable speed belt drive used in earlier models.

Anyway, in its second season, the hydrostatic transmission gave trouble. Downtime during harvest was always guaranteed to elevate Dad’s stress level to 11 out of 10. And that wasn’t a pretty sight… read the rest of this story.

Yours for better hydraulics knowledge,

Brendan Casey