Hynautic H50 Repair & Bleeding

These steering systems can be tricky to repair and bleed, some have gone so far to say that it can’t be done without extensive training and experience.

I’m not convinced that is exactly true. Have a look at my video and determine if this is a task you feel comfortable tackling. If you came here from the video, look down a little lower for the bleeding instructions and exploded diagram!

Things in this article/video
Helm seal kit HS-01
Seastar fluid (1qt)
Aeroshell 41 (1 Gallon) (Alternative fluid approved by Seastar)

13 Comments on “Hynautic H50 Repair & Bleeding”

  1. Rebuilding a Hynautic H50 Hydraulic steering helm, All new seals, No more leaks!

    Thank you for the nice video.
    I replaced the seals and reassembled the unit. No Leaks. Bled the system.
    The wheel will turn the ruder to the right, but will not turn the rudder to the left?

    Help Please

    1. Hi Alan!
      Does the wheel turn smoothly in both directions? or does it bind up turning to the left?
      I had a miserable time bleeding the system this helm came from, I had to bleed each helm (there was 2 on this boat), as well as the cylinder and all the lines, it took several attempts going through the bleeding instructions before it would cooperate.

  2. I am having that trouble. It will go to left when the bleeder valves on the reservoir are closed but free wheels to the right? I had no problem before I changed the seal kit and have even replaced the upper helm steering with Sea star conversion. Going to check the that the hoses are correct tomorrow.

    1. There is likely a little entrapped air, it took me forever to get this system bled, I thought I was done, and I had to re do both helms several more times because of the fluid I lost while rebuilding the helm.

  3. Hi Jarod,
    Thanks for the video it was very clear and easy to follow. However, we neglected to make any alignment marks and rather than have the two Xs to line up to, I understand we have an E and an X. Just wondering if you have any suggestions for how we can figure out the alignment?

    Thank you,

    1. I’ll have to look at the spare helm I’ve got sitting here, I’m not sure I’ve seen an E marked and not an X, perhaps it is a derivative or has been repaired before or something, Either way, I’ll take a peek at this helm of mine and see what I can see, hopefully find something useful for you!

    1. Maybe, it may just end up pushing oil out of the other helm, but in theory, I’m not sure in practice, but in theory the check valves should keep the oil where it needs to be, but I would be incredibly careful just in case those check valves don’t hold and you end up losing steering while under way.

  4. Hi Jarod,
    My upper helm H 50 is leaking at the shaft seal. It’s on a Bayliner 3288. Is there no way of purging air at that station after I replace seals as per your video since it is at the highest point, without having to bleed the entire system? It sounds arduous but if bleeding entire system is the only way, how much hydraulic fluid should I have on hand to bleed and fill?
    Thanks so much! Ray

    1. So generally you won’t need much fluid, as it will circulate through the purge valves that you open, so there shouldn’t be fluid spraying anywhere or leaking, when I did this helm and bled I used somewhere around a quart or less of fluid.
      I’m not sure what would happen if you pressurized the system and then cracked each line at your top helm after the rebuild, but I suspect it would be very messy, but it might get a lot of air out, which may make the bleeding process far simpler, I’m honestly not sure.

    1. You should be able to find a model number on the back of the helm, Always starts with an H if it is a Hynautic unit, after Teleflex bought them out it may have changed.

  5. hi! Great video.
    I’m not leaking H50, but I have another problem. The boat is prowling and when I turn the steering wheel, I hear the bearings. Isn ‘t that wrong ?
    Can replacing the seals help or is it better not to touch if it does not leak ?

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