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zincs on hydraulic lifts causing leaks?

Discussion in 'Technical Discussion' started by Bamboo, Nov 28, 2017.

  1. Bamboo

    Bamboo Senior Member

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    Has anyone had a worn/used up zinc found to the cause of a hydraulic leak on an aft lifting platform?
  2. Capt J

    Capt J Senior Member

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    Yes, it can. If there is electrolysis it can eat up the shaft on the rams and cause the seals to get eaten up......it's a very remote situation though and if the lift is done properly by the manufacturer usually the ram shaft and seals sit out of the water.....
  3. Bamboo

    Bamboo Senior Member

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    Have you seen this happen on new vessels?
  4. rcrapps

    rcrapps Senior Member

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    SeaRays; Yes
    Same lift company makes the same assembly's for other boat mfg's also.
  5. Capt J

    Capt J Senior Member

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    Yes, on a 1 year old Prestige that had electrolysis issues.
  6. T.K.

    T.K. Senior Member

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    I have seen the same problem on Volvo Penta DPH stern drives. The steering rams and the trim rams were leaking hydraulic oil from around the shaft due due to galvanic corrosion of the ram body especially the area around the shaft seal. This occured on a vessel which was only months old. The hydraulic rams were replaced, more stainless steel grounding wires fitted to the DPH drives and realated components including fitting a galvanic isolator on the shore power lead and the problem never reoccured. The boat is now 5 years old.
  7. Bamboo

    Bamboo Senior Member

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    No leaks since I stopped leaving the platform above the water but lower than all the way up. The zincs were at about 65%-70% so zincs/corrosion was not the issue. I believe leaving it less than all the way up was the issue as that is the only factor which changed and the leaks ceased.
  8. rcrapps

    rcrapps Senior Member

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    I must have took a wrong turn somewhere. Maybe Albuquerque..:)

    Can you expand on this a lil more please? What relation to water level would the zincs, seals, other hardware have change to stop the leaks?
    Or maybe, less pressure on the rams making the leak from all the way up?
    Less weight out of the water?
    Could you expand on the design or mfg? Drawings or pictures could help.

    A few systems I have had anything to do with has a latch to capture the platform, lock it up and relive pressure from the cylinders. Maybe this is a part issue.
    Last edited: Dec 7, 2017
  9. Capt J

    Capt J Senior Member

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    The shaft is corroded where the seal sits on it in the all of the way (natural) up position. Saltwater probably sits in the seal where it meets the ram. Doesn't the lift have safety locks that engage when it's in the all of the way up position? Some do and some do not.

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