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Lessons learned — the hard way

Dust shield or O-ring?

By Tom Nash,
Applied Industrial Technologies

Tom Nash

While at an automotive plant, I noticed a worker repeatedly stopping, picking up a bucket, and pouring fluid back into a hydraulic reservoir. I asked why he had to keep refilling the reservoir with new oil. He said, “Oh, it’s not new oil, we just have a bad leak, and we have to empty the bucket every few minutes.” When he found out I sold pumps, he asked for a sump pump so he did not have to empty the bucket so often.

I went to look at the source of the leak. A funnel duct-taped to the side of the machine drained into a piece of steel pipe that went across the machine to a section of flexible tubing, which dropped into the bucket. The operator said many people could not figure out how to stop the leak. He explained that they had installed a 4-ft “cheater” pipe on the end of the wrench but could not get the nut tight enough, so they created this exterior drain.

When I returned after finding what looked like the correct fitting, they said they had tried several fittings but none worked, so there must be a crack in the machine. The mechanic pulled off two protective caps and cut the O-ring off the fitting. I asked him why he did this. He explained that the O-ring was part of the protective shipping to prevent dust from getting in. I picked up another adapter and asked if he would leave the O-ring on just to humor me. To their amazement, the leak stopped.

Lessons Learned are contributed by Cleveland-based Applied Industrial Technologies’ Fluid Power Specialists. Tom Nash is Applied’s Product Manager - Fluid Power Products. He has 20 years of technical, sales and managerial experience in the fluid power industry. Contact him at (216) 426-4257, [email protected], or visit

Lessons learned:
Hydraulic leaks are almost always correctable, and it is easy to overlook a simple O-ring, seal, or gasket that may be required to prevent a leak. It’s just as easy to install an improper O-ring, seal, or fitting. Just because the fitting fits doesn’t mean it’s working properly. Double-check your fittings and call a fluid power exp
TAGS: Maintenance