Hynautic steering does not work

[jwnall]

The steering on my 1973 Gulfstar 36 trawler has gone out. From what I gather, this is a Hynautic hydraulic steering system. Unfortunately, although I had a lot of sailing experience before buying this boat last September, I am completely ignorant of hydraulic steering system.

So I hope that some of you may be able to offer some help. When I brought the boat over from the East coast of Florida to St. Marks (Northwest Florida) the steering was working fine. The previous owner told me that I needed to keep the reservoir filled with ATF and to keep it pumped up to about 40 psi. I did not take any ATF along on the trip over here, and when I got to my slip it was very low. It has sat in the slip since September, for various reasons, and last week I filled the reservoir and tried to pump up the pressure. It seems to not hold the pressure however, and the steering wheel has no effect on the rudder.

I do not expect any of you to solve the problem for me (although it would be nice!) but perhaps you can tell me where to start.

Thanks,
John

[atoll]

you need to find the leak and fix it.

then you need to bleed the system completly to get any air out,whilst topping up the reserviour,then repressurise.

bleeding is done at the ram,by opening one of the bleed valves,turning the wheel to port untill clear fluid with no air flows.
then open the oppsite side bleed valve on the ram and turn wheel to starboard untill clear fluid flows with no air.,

care is needed to keep filling the reservoir whilst turning the wheel,re pressurise once system is bled,and check for a drop in pressure over a few days to acertain if you still have a leak.

most common source of leaks is the orings on the ram,next is the flexible hose to the ram breaking

[Lancerbye]

When you mentioned Hynautic memories of their throttle and shift system came to my mind. Had one on a commercial fishing boat some years back. They employed the air over fluid under pressure for that system as well. The big fear was having the fluid go low, and the air being pressurized over it, getting into the lines etc. It took a lot of bleeding and filling to get the system back to normal and this was on vertcal rams. If your system has a horizontal ram for steering which is the most common the the process of evacuating the air can be more painful. Make sure your bleed hoses are at the top of the cylinder. Keep the pressure up after every fill and keep bleeding the air out. Once all the air is out of the ram you will have to pump up the system with a full reservoir and run all your steering stations from lock to lock several times. However first you have to find the leak. It has a zero tolerence for leaks as the pressurized system will force fluid or air out of the leak point. If you still don't get rudder movement the ram piston O-Ring or packing is probably gone. Listen for fluid movement through the cylinder while someone operates the wheel.

[Cheechako]

I had that exact same pressurized system. Check throughout for leaks,mine needed air now and then but seldom any fluid. Google "bleeding hydraulic steering" and you'll find out how to do it. You basically start at the highest helm in the boat, and work the system until the air is out, while filling. There are good diagrams under Sea Star or Hynautic of various systems. It's not complicated, just a rotating pump that pushes fluid to a hydraulic cylinder connected to your ruddder. The first thing I would chek is the cylinder and related hoses.... most leaks or hose failures occur there. Your boat may have copper lines with short flex lines near the cylinder, or flex lines throughout. These can be made up custom by a hydraulic hose place.

[Kettlewell]

Are you sure it is ATF you're supposed to use? Maybe it is the same stuff, but there is hydraulic fluid specific to steering systems.

[Cheechako]

I hope someone knows this, I used the stuff you show there, but have heard ATF is fine. The seastar fluid is like buying gold!

[delmarrey]

Here's an owners manual>>> http://cworthy.net/boat/documents/Hy...s%20Maunal.pdf

Personally, I don't like pressurized reservoirs but what can you do if one can not get the reservoir up high enough for a gravity feed.

Originally Posted by Kettlewell

Are you sure it is ATF you're supposed to use? Maybe it is the same stuff, but there is hydraulic fluid specific to steering systems.

Ditto! The problem with ATF is it needs heat to dissipate moisture. Whereas the Pro-fluids have an additive to do that.

[sww914]

The thing about bleeding hydraulic steering is going slow. Turn the wheel(s) slowly and let it sit at the end of it's range for 2-3 minutes without moving it.
And by slowly I mean slow enough that you cringe the whole time, wishing like hell that it was over.

[SVNeko]

Lecomble & Schmitt recommend the red ATF - forget the exact designation - for their hydraulic units. Its a lot cheaper and easier to get in out of the way locations. Agree with Steve, but also its a 2-man job. Keep a little pressure on the wheel at the stop to keep the pressure up.

[Kettlewell]

I have used standard hydraulic fluid purchased at places like NAPA auto parts for years with no apparent issues.

[Hudson Force]

I have used a 10W hydraulic oil for many years,- I'm sure there are some options that are compatible with your seals. My best success with bleeding air from the system is to open the fittings at the highest point. For me this is at the pump driven by a chain linkage just at the bottom of my binnacle.

[jwnall]

Thanks for all the good advice. I went down today and bled the system, and it seems to work OK now. Have not located the leak yet. I talked to the previous owner, who is a very savvy boat person, and he said that he was never able to locate it, so that one may take a while to gun out. For now I'll just have to add fluid from time to time.

John (OP)

[Cheechako]

To find the leak use TP or paper towel, touch every inch of line until you find fluid. A little bit does tend to occur, but evidently you are looking for a little more than that....? or maybe if the boat is new to you it just hasnt been checked forever. My maintence supervisor responsible for up to 200 hP hydraulic units used to say: " if it aint leakin', it aint hydraulic"

[jwnall]

Originally Posted by Cheechako

To find the leak use TP or paper towel, touch every inch of line until you find fluid. A little bit does tend to occur, but evidently you are looking for a little more than that....? or maybe if the boat is new to you it just hasnt been checked forever. My maintence supervisor responsible for up to 200 hP hydraulic units used to say: " if it aint leakin', it aint hydraulic"

It does not appear to be a serious leak. I brought the boat over from the East Coast of Florida on a trip that took ten days, and did not add any fluid during that time. When I left the reservoir was half full, and there was about an inch showing when I finally got here. But for various reasons I have let it sit in the slip for six months without running it, and that seems to have caused the problem. That said, I will definitely try and find the leak, using your suggestion.

John

[Cheechako]

from half full to an inch is a pretty good leak, and something got it to half in the first place, it could fail completely or just need tightened up. My boat needed about a tablespoon every year.