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 iboats.com 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.

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

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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.

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

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

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You can save yourself a lot of work if you’re 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 ½”. After I had the case loosened and down 1/2”, 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 don’t need to do if you’re careful.

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If your pump is clean on the inside you don’t 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 can’t go wrong.

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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.

Mike

Thanks several years too late. Mike, can you add to your instructions the correct allignment when the housing is assembled to the base for those who have not done this. I had it aligned wrong before I found the trick. Also the body is marked with an S and P for Starboard and Port hoses.
As I mentioned before, aside from the leak in the seal I found I had greese everywhere. I had to clean everythig to get the greese off the bearings,springs and the small pistons.
Also good for your pictures would be to show a picture of the pistons and they can only be rotated in one place to be able to turn the wheel. If not it jerks when you turn the wheel. I've done that wrong also.

Here is what the alignment marks are suppose to look like . I couldn't see the marks on the cover so I scribed a line on both pieces and matched them up when I put it back together.

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I was going to take pictures of the piston, springs and all the goodies inside and that's when it slipped out of my hand and spread all over the garage. By the time I found and cleaned all the parts, more pictures was the last thing on my mind.

Mike

I saw that on the instructions when I first rebuilt the helm but I didn't know what it meant. I couldn't see the X anyway on one of the parts. Since I normally make a mistake and I didn't align the marks right, when I turned left the OD turned right. Another 1/4 turn and the wheel locks up until I figured it out.
I had ball bearings under the freezer and dryer. So when it's taken apart it's in a cardboard box.
Go Chargers!!!

Nice job on the helm repair. I have heard guys havibg the same issues you had, its very common to have the pump come apart.
Hijole: Do you think the grease eat up your seals? It must have been a job to clean up that mess.
Good Job.

Bob

No I don't think it ate them up. I think the greased did what it's supposed to do. It made eveything in my sytem smooth and slippery. Not what we want in a hydraulic system. On my last cleaning I removed every component (helms, pump, ram, tank and lines) and cleaned it thourougly. It has been great for 6 months. I wanted to get a new system also but I'm glad I stuck it out and I think I found my problem.