In The Hydraulic Troubleshooting Handbook I define and explain 12 principles for troubleshooting anything successfully. And I use examples from various fields of endeavor, in addition to hydraulics, including medicine and IT. Troubleshooting Principle #5 is: Never Take Anyone Else’s Word For It. And I observed a good example of the application of this principle recently when, after moving from one side of the country to the other, I was having trouble with my broadband connection. I was on the telephone to a technician in my ISP’s support department. Keep in mind these guys are professional tr ..read more

As every hydraulics user who’s been around for a while knows, hydraulic component manufacturers are notorious for the smoke and mirrors they use to deny warranty claims. Now, this is NOT to say all warranty claims are legitimate. In fact, it’s very safe to say they’re not. But when a hydraulic component fails prematurely, what IS needed is accurate information, i.e. better answers than ‘it’s contamination’. And the reason why is illustrated by the following story about a client of mine who had suffered a series of failures involving a particular brand of radial piston motor. When he first went ..read more

One of our members wrote to me regarding the following problem: “We have a hydraulic system that operates two cylinders. The maintenance staff recently reported that the pump (piston-type) had failed – for reasons unknown at this time. The tank, valves and cylinders were cleaned and a replacement pump installed. The new pump is delivering a maximum pressure of 1,000 PSI and appears to be creating heat. Can you suggest some tips to find a solution to this problem?” In any troubleshooting situation, no matter how simple or complex the hydraulic system, always start with the easy things first. Th ..read more

A manufacturing company recently hired me to check the performance of four hydraulic pumps operating a large hydraulic press. The hydraulic pumps had clocked over 10,000 hours in service and the customer’s concern was that if pump performance was down, production would be too. My test results revealed that the performance of all four pumps was within acceptable limits. So in my report, I advised my client that there would only be a minimal increase in productivity if the pumps were replaced. I further advised that the change-out of all four pumps should be scheduled urgently! The foundation fo ..read more

In my previous articles on hydrostatic transmissions, I described the technique for determining the condition of a hydrostatic transmission using case drain flow, and discussed the role and influence of a flushing valve when doing this. In response to these articles, some members were still confused about the influence of the charge pump when determining case drain leakage from a hydrostatic transmission. One reader held the view that, assuming the charge pump relief valve vents into the case of the motor and the motor case drain line is isolated from the pump, then transmission pump leakage i ..read more

Despite his mother’s horror and protestations, my 18 year old son recently bought a motorcycle. It’s a Japanese, hog style machine. Ben would quite like a H.D. but that’s WAY out of his price range. The bike he got is 13 years old with 15,000 km (9,300 miles) on the dial. So he didn’t pay a lot for it. In fact, his bike clothes and safety gear cost almost as much as the used hog. Anyway, being that he’s young and this is his first bike, he’s like a lamb with two tails. Not long after he departed for his third outing on his new machine I get a call. “Dad, my bike has broken down”. When I asked ..read more

In The Hydraulic Troubleshooting Handbook, I explain 12 principles which must be adhered to in order to solve any hydraulic problem effectively. Troubleshooting Principle #1 is: check and eliminate the easy things first. The benefits of this mandatory first step are clearly illustrated by a troubleshooting situation I was involved in recently. The machine in question had a complex hydraulic system, the heart of which comprised two engines driving ten hydraulic pumps. Six of the pumps were variable displacement pumps and four of these had electronic horsepower control. The symptoms of the probl ..read more

Would you part with $87 to save $70,000? This is a ‘no brainer’ for most of us, right?. Well, here’s a story for you: I recently conducted failure analysis and a reliability audit on a 300 kW hydrostatic transmission. The hydraulic system was running a synthetic ester, biodegradable hydraulic fluid. This $45/gallon hydraulic fluid had been destroyed in under 12 months and a set of pumps shortly after. So with $20,000 of hydraulic fluid and $50,000 of pumps ruined in short order, my client was understandably wondering what went wrong. The system was built and installed by a reputable distributo ..read more

How many different types of hydraulic oil are taking up space in your oil store? If there’s more than one you’re not alone. I often get questions from members who’d like to consolidate their hydraulic oil inventory but aren’t sure how to go about it. This one is typical: “We have a number of pieces of hydraulic equipment e.g., bucket trucks, cranes, backhoe, rollback wrecker, dump trucks, scissors lifts, etc. It seems like each piece of hydraulic equipment requires a different hydraulic oil. I’d like to know the compatibility or interchangeability of the different products before I do irrevers ..read more

In this previous post on hydrostatic transmissions, I outlined the theory and technique for using case drain flow to determine the condition of a hydrostatic transmission pump and motor. In response to this post, some readers thought that the function of the flushing valve warranted discussion, while others were still confused about the influence of the charge pump when determining case drain leakage. Let’s consider flushing valves first. What is a flushing valve? A closed-circuit flushing valve (also called a transmission valve or replenishing valve or hot oil purge valve) usually comprises a ..read more