Helm wheel spinning

[winty]

Greetings

'81 CHB34, dual hydraulic steering stations + auto pilot. All three stations use the same "Stylen" pump.

I've been struggling with this issue for the past 6 months. At first it was intermittent and only occurred after full lock to stbd or port. Turn one wheel, and the other spins in the opposite direction with no ram movement. Now the issue is constant, no ram movement, only wheels spinning in opposite directions. The get home fix has been to lash the lower wheel to a grab handle in the house, and steer from the fly bridge.

Two different techs have attempted to troubleshoot. First guy was just a general fix it / mechanic. He changed fluid, bleed out the air, greased tiller. Second attempt was a hydraulic steering tech, he also changed fluid and bleed for air. Concluded check valves in them helm pumps must be seized. He recommenced replacing all, pumps, ram, lines.

Not ready to accept a full steering system replace, I pulled the helm pumps and shipped to a hydraulics shop in Massachusetts. They tore them down, cleaned, tested on a machine, passed as functional and returned. I installed and bleed, same spinning wheel issue.

Next, bypassed auto pilot pump and auto pilot lines from system. New fluid, same issue.

At this point I've flushed the fluid 5-7 times and in the process have switched from the expensive west marine fluid to standard ATF.

Today I pulled this valve assembly from the stern of the boat. What is it? It does not look like the teleflex uniflow valve I see on many forum posts. It has return air vent line on the top center. I took it apart and checked the slides and valves, all action is smooth and no dirt or gunk in any of the passage ways. I will replace the o-rings, but I don't see that as the solution.

How do I fix the steering? Advice greatly appreciated.

 

[BryanF]

In spite of the test and clean bill of health- either the helm pump check valve is not holding or the ram is bypassing big time. See if you can borrow a ram and switch it over. If the problem goes away... well good. If not back to the check valves.
My 1/2 cent over the internet diagnoses. YMMV.

 

[Forkliftt]

Ditto here. If the wheel is turning, that is the "work" produced when you spin the other wheel. Sorta like spinning the wheel takes the place of hydraulic cylinder rod movement.


1983 Present 42 Sundeck
Twin Lehman 135's

 

[bglad]

How hard is it to turn the wheel when one is lashed? Do both helms motor the other when they are not lashed? If the steering is stiff when you are actually moving the cylinder it may indicate a problem with the cylinder itself. Some have plastic plungers that hold the seals inside the cylinder and I have seen them swell to the point the wheel cannot be turned. Perhaps in your case it causes the oil to bypass the helm pump check valves. Never seen or heard of it happening but we are grabbing at straws here...

 

[winty]

Thanks for all the replies.

>>How hard is it to turn the wheel when one is lashed?

Two fingers, feels normal. It was slightly lighter before I switched to ATF.

> Do both helms motor the other when they are not lashed?

Yes. Also if auto pilot is active it will spin the wheels not ram. However, auto pilot has been removed to troubleshoot.

I will start asking around for another ram to test.

 

[Ski in NC]

What exact helms are these?

Most helms have internal valving that isolates the internal pump from flow unless that wheel is being turned. If a wheel turns without your hands on it, the internal valving on that helm has stuck.

Some old helms did not have this valving, and did turn with the other. But since this problem started as intermittent, sounds like yours are the modern type.

Problem is not with the ram or the ap or the bleed block. It sounds like it is in the helms.

 

[winty]

Here are images of the autopilot pump, which is the same pump as the two steering stations.

I had a shop clean and test the two helm pumps however, I'm not sure how to verify the work on my side.

 

[bglad]

I agree it is not the cylinder. If there is no unusual resistance it just has to be the check valves. Very strange for both helms to fail the same.

What exact helms are these?

Most helms have internal valving that isolates the internal pump from flow unless that wheel is being turned. If a wheel turns without your hands on it, the internal valving on that helm has stuck.

Some old helms did not have this valving, and did turn with the other. But since this problem started as intermittent, sounds like yours are the modern type.

Problem is not with the ram or the ap or the bleed block. It sounds like it is in the helms.

 

[rochepoint]

My boat did the same thing, the autopilot made the upper helm spin and it was a dirty check valve on the upper unit, my helm units were Capilano. Why not have a conversation with Teleflex now owned by SeaStar. SeaStar marine hydraulic technical support division is in Vancouver BC Canada at 1-604-248-3858 or email info@teleflex.bc.ca. They were great and gave me the solution to my problem.

 

[Ski in NC]

That's a "Sytten" system. Not sure if those helms have the internal blocking valves or not. Not sure what that transom mounted valve does, might just be relief valves.

Might bite the bullet and upgrade to modern helm pumps.

 

[rochepoint]

Thanks for the correct spelling, a google search came up with a post on The Hull Truth from SeaStar saying no parts available any more and they recommend replacing them.

Not good news but I would still email them.

 

[winty]

Any suggestions on a replacement pump which will work with existing ram?

 

[winty]

Update. Purchased new everything.

New helm pumps, new lines run, new cylinder, new autopilot, new mounting brackets and or adapters. I have slowly installed over the past 3 weeks. Steering is working. Autopilot is installed, but I have not had time to power up to test.

Thanks for the help on this one. Another boat lesson in, throw away old components and start fresh, vs trying to fix, failing 3 times, then buying new.