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My lead mechanic said to never trust a new seal out of the box, and a 737's hydraulic pump proved him right
He told me this five years ago when I was a new hire. Last Tuesday, I replaced a pump on a 737-800 and the new O-ring looked perfect. I almost just slapped it in. I checked it anyway, and there was a tiny, almost invisible nick right on the sealing surface. If I hadn't caught it, we would have had a massive leak on the next flight test. Who else has a rule from an old head that saved your skin like that?
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max_ramirez481mo ago
My buddy in heavy equipment had a foreman who always said to check new hydraulic hoses for liner cracks. He laughed it off until a brand new hose blew on a test run. The inner liner had a split you couldn't see from the outside. It sprayed fluid everywhere and shut the job down for half a day. That old guy's rule about inspecting every single new part became gospel after that. It seems paranoid until you see it fail.
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the_lucas1mo ago
New stuff fails way more often than people admit, it's not just old gear.
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harperschmidt1mo ago
That liner crack story hits close to home. I've seen the same thing with new CAT hydraulic lines on a 336 excavator - inner layer failure in under 50 hours, zero visible damage on the outside. How do you even catch that on a standard walkaround inspection without pulling the hose apart?
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