Hynautic steering (antique)

nodestination · 02-09-2017, 04:39 PM

I am having problem with my steering - can not keep the air pressure. It supposed to be 20 psi at all time, but I do not see any hydraulic fluid leaks. Oil level constant. The H-21 pump does make some noise but work. I have "hard time" to locate the reservoir - I think that there is my problem. I did replace the copper lines and bypass the auto pilot to eliminate the leak. It is 1973 Gulfstar 36. From what I read - the air pressure is there to keep any bubbles away, but should not affect the steering if the system is "tight". I got good steering from the bottom, but got sloppy from top.

Salish Nomad · 02-09-2017, 07:30 PM

If you're not leaking hydraulic fluid, then it's likely losing air at the reservoir. You can use a soft brush and soap suds to check for air leaks once you have re-pressurized the system. The Schrader valve in the filler cap is a likely suspect, as well as the filler cap o-ring.
The noise in the h21 helm is not uncommon, as it is a rotary piston pump.
Imho Hynautic is a quality product, I sold, and installed them for many years.

nodestination · 02-09-2017, 07:47 PM

I did replaced the valve, but still no luck. I notice that the valve house is damage and the relief valve can not be screw properly - thread damage. Where I can find the reservoir?. Mine have plastic tube ( fluid level). The others I saw have section fluid level.

Salish Nomad · 02-09-2017, 08:04 PM

I sent a private message with info that should help.
From you photo, yours is the older style with the the built in air pump. Any of the Hynautic steering reservoirs will work as a replacement.

nodestination · 02-10-2017, 07:29 AM

Got it. Thanks.What is that "thing" on left of gauge?. The bottom of that "thing" have a thread but will not tight down. I believe that is mess up.

bilge53 · 02-10-2017, 08:43 AM

My bet would be the pump is leaking air if no other leaks visible elsewhere. Soap mix with water and look close for bubbles. Where air goes in air can come out.

menzies · 02-10-2017, 08:59 AM

Quote:

Originally Posted by nodestination

Got it. Thanks.What is that "thing" on left of gauge?. The bottom of that "thing" have a thread but will not tight down. I believe that is mess up.

That is a small finger pump which does not screw down. You should be able to pump it up and down and it will add pressure. It could very well be that the valve at the bottom of that is worn and leaking air back out.

Salish Nomad · 02-10-2017, 12:17 PM

That's the air pump. The pump assembly should unscrew from the reservoir top plate. You may be able to locate, and replace the entire pump assy. if that is where your air leak is. Or if you can remove the pump assy., then simply fit a solid plug into the hole, you can use a bike tire pump to pressurize the reservoir. many of the Hynautic system reservoirs were configured this way.

bilge53 · 02-10-2017, 01:23 PM

I use a Harley Davidson pump (same for my shocks and air bladder police seat). It is small, has a mechanically flexible hose/connector and best of all attaches and detaches with no loss or change in pressure. It has a gauge attached which is very accurate and readable. I highly recommend for this application.

nodestination · 02-11-2017, 11:51 AM

Thanks for the info on that pump. I have 3 manuals, but none of them mention the punp. I will block it and see what happen.

nodestination · 02-13-2017, 12:06 PM

I did remove that air pump - it was leaking. The whole assembly is "mess up". I did block the hole, but still , somewhere, I have a leak. What is the purpose of the air in system. Can I drive without?. Someone told me that the air pressure is there to pump the fluid to upper station. If that the case, would be more easy to just put the reservoir in upper station?. Thanks.

Salish Nomad · 02-13-2017, 01:32 PM

You DO need the reservoir pressurized to provide fluid to both stations. The replacement solid plug with Schrader valve is hp6040 (Teleflex SeaStar).
The complete reservoir is hp5810hy.
Hope this helps. You can see photos on sea mar.com website.

nodestination · 02-13-2017, 03:52 PM

Something wrong with the mar.com website.

nodestination · 02-13-2017, 04:09 PM

Can I just replace both pumps with BayStar 1.1 HH4311-3 and get raid of the reservoir?.
I had those pumps on my 1974 Marine Trader 34.

Salish Nomad · 02-13-2017, 04:41 PM

That would probably work, keep in mind the displacement should be close to what you have currently, I believe the h21 is a 2.0 cu in. Pump, also you might make sure the steering wheel's will fit the new pumps. Good luck!

twistedtree · 02-13-2017, 06:49 PM

The Hynautic systems are pretty good, and the pressurized reservoir makes bleeding a bunch easier. If I were you I'd track down the leak, and perhaps rebuild the two helm pumps.

nodestination · 02-15-2017, 10:38 AM

I eliminated the reservoir as source of a leak. The pressure gauge do not shows any fluid leaks. If the gauge will leak, it will shows a fluid leak, but is none. If I am correct, the gauge register fluid pressure and not air pressure. If any pump would leak, will the fluid shows or the air will leak without fluid leak?. Thanks.

nodestination · 02-19-2017, 07:12 AM

Victory after all. I found the source of the leak and now I have steady pressure. It was the 2 bolts that hold the reservoir - were leaking on back, that is why I could see. I use small mirror and found the bubbles. All work fine now.

menzies · 02-19-2017, 07:17 AM

Good job!

Salish Nomad · 02-19-2017, 12:30 PM

Glad you were able to fix it!