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Update on that weird noise in a 90s Dover hydraulic unit I was chasing in a Tacoma office building
After three hours of checking everything from the pump to the valve, I finally found a worn guide shoe on the plunger that was making a faint scraping sound only when the car was descending with a light load, and replacing it with a new one from my kit fixed it completely, has anyone else had a noise that specific to load direction?
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the_oliver5mo ago
Check the plunger rod for a slight bend too.
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evan_grant705mo ago
You mentioned the noise only happened when the car was descending. That's a key detail, but on a Dover unit, the load direction is actually tied to the car going up, not down. A light load going down is basically the counterweight doing the work. That faint scraping on descent was probably the shoe just kissing the guide rail because the plunger was tilting without much hydraulic pressure behind it. I've seen that exact thing on a few 90s installations where the guide shoe wear gets uneven.
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matthew_west5mo ago
I read a service bulletin from a few years back that talked about this exact thing on the older Dover units. It said the guide shoe material from that time could get brittle and wear in a weird pattern. The bulletin suggested checking the plunger alignment whenever you replace one of those shoes. Your find makes total sense with what I heard.
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