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Thread: Hynautic Helm Seal

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  1. #1
    Join Date
    Apr 2004
    Spring Valley

    Default Hynautic Helm Seal

    Hynautic H-50 series helm pump seal replacement

    I had a small amount of fluid leaking at both my helm pumps after 27 years of service. I wanted to catch the problem before it turned into a full rebuild so I ordered 2 seal kits from for $26 a piece.

    The first thing you need to do is release the pressure in the tank.

    Start out by pulling the wheel off the helm pump. Loosen the set screw that hold the center cap, remove the cap and then the nut from the pump shaft.

    You will need a small gear puller to remove the wheel from the pump shaft.

    Tag and remove the 3 tubes from the back of the pump. Put a towel or some oil absorbent pad down to catch the drip.

    Remove the 4 screws that hole the pump in place and take it
    to the garage or a clean area for tear down.

    Remove the 4 bolts that hold the black pump cover to the pump body.

    You can save yourself a lot of work if youíre careful in the next few steps. The black case needs to slide off the pump shaft but there are 3 o-rings that make it a tight fit. I found it was easy to stand the pump face down on the shaft and tap evenly with a hammer until I had it off about ĹĒ. After I had the case loosened and down 1/2Ē, I flipped it over (shaft up) and worked the pump cover up the rest of the way by hand as I pressed down on the shaft. You need to keep the shaft shoved into the pump as you do this or you will have 100 springs and ball bearings in your lap that will need to be restacked. Not a problem, just a little extra work you donít need to do if youíre careful.

    If your pump is clean on the inside you donít need to tear it all the way down for cleaning, just clean the pump shaft, replace the 3 large o-rings that seal the pump case and change the shaft seal and o-ring. The kit comes with seals for pre 1985 and post 1985 pumps. Follow the instruction that come with the kit and you canít go wrong.

    The kit comes with instruction on how to fill and bleed the system when you have everything back together. Took me about 3 hours from start to finish for both pumps including the half hour I spent looking for springs and ball bearings on the floor of the garage when the second pump slipped out of my hand when I was taking pictures.

    Last edited by NoSlack; 01-12-2019 at 04:58 PM.

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