Hynautic Steering Issue

[oscarvan]

There's more going on but I don't want to over complicate it.

Short version is that a new autopilot pump was installed, and as a result I had no steering, or more correctly, sketchy steering at lower helm. Many turns some movement..... On a sea trial at WOT, but i digress. Air in the line.

Yes I have the instructions and I unscrewed the pressure relief valves as per procedure, BUT..... even after doing that the upper helm is still moving the rudder and limited to it's 4-5 turns, in other words it's not by passing allowing me to do the 40 turns and move the fluid through the system. Upper helm is working correctly though.

My next step is to crack the lines at the lower helm, but I am still scratching my head as to why I can't bypass the piston......

 

[Captain Ralph]

All Hynautic bleeding is tone at the T block.
Reservoir full and under pressure, open the relief screws and turn, turn, turn.

No line cracking.

Yes, the rudder may move but the wheel will not stop and keep rotating.
If it does stop, the screws are not fully backed off or a bad T block.

 

[krush]

What Mr Ralph posted is exactly correct. Bleeding a hynautic of air is the most stress free and simple hydraulic bleeding procedure you will ever encounter.....provided the relief valves are opening.

Only open one relief valve at a time.

 

[oscarvan]

One at a time? That's not what the book says.....

When you say "T-Block" do you mean the MSV-21, shown below?

There are bleed nipples on the piston, I don't see any on the MSV21

 

[Boatsb]

3 out of 4 autopilot issues are install problems.

The line path and position could be the issue. The bleeding of the pump too. Get the installer to fix it.

 

[jmooney]

No fluid is bled out of the system. Opening the relief valves allows fluid to go back to the reservoir taking air with it .

 

[oscarvan]

OK after talking to the man who has installed more Hynautic systems than he can remember it appears I have a sticky valve in the MSV21. I will replace.

 

[Captain Ralph]

One at a time? That's not what the book says.....

When you say "T-Block" do you mean the MSV-21, shown below?

There are bleed nipples on the piston, I don't see any on the MSV21

Yes, My bad term.
Those brass screws, screw up about 3/4". they do not come out but will stop at end of travel.
Then turn,, turn,, turn the steering wheels and AP pump while checking on fluid level and pressure.

Yes, later cylinders had bleed nipples. Unless that ram was removed, I would not worry about going there.

 

[Captain Ralph]

OK after talking to the man who has installed more Hynautic systems than he can remember it appears I have a sticky valve in the MSV21. I will replace.

If one steering pumps is working and the others not, I disagree.
The MSV21 is common to all 3 of your heads. If one of the three has an issue at that pump,, of course after bleeding all well.

 

[Captain Ralph]

Now, since all of this started when the AP pump was installed,
AND I'm sure service valves were installed,
have you closed off the AP pump and checked for problems?

Because it's new, does not guarantee it is fault free.

 

[Pascal]

It s always on survey day. Reminds me of last year when I was coming back down the channel at 20kts and lost steering altogether on the 84. Slowed down using asymmetrical thrust to stay between the stick. Nobody noticed something was wrong turned out to be a broken bronze tiller arm

Anyway… if the upper helm is working it’s easy because of how the pump was plumbed or air got in the lower helm somehow. Have you tried basic purging by turning the lower helm until it stops then back the other way? That has always cleared air bubbles for me

 

[oscarvan]

Have you tried basic purging by turning the lower helm until it stops then back the other way?

Yes. I gave up at 100 turns. It's not moving fluid most of the time.

 

[Pascal]

Any shut off valves for the lower helm what may have closed? I sounds like an issue with the helm pimp itself

 

[bigbill]

hynautic says open both relief screws, turn the upper most wheel to the right about 50 turns slowly, then the same direction on the next lower wheel then make the auto p[ilot pump turn the same direction, then do the same procedure and turn the wheel to the left. then close relief screws...BUT, i have to ask why not call the installer and have them fix their mistake?

 

[Yachtsmyth]

just my 2 cents- but it might be the new auto pilot. is it the correct pump?

 

[Captain Ralph]

Installed correctly, just takes a second to eliminate the question;

Close the service valves.

 

[oscarvan]

Bypassing high pressure valves now working. Guess the springs eventually saw the light. Cylinder removed to rebuild.

 

[oscarvan]

hynautic says open both relief screws, turn the upper most wheel to the right about 50 turns slowly, then the same direction on the next lower wheel then make the auto p[ilot pump turn the same direction, then do the same procedure and turn the wheel to the left. then close relief screws...BUT, i have to ask why not call the installer and have them fix their mistake?

Did all that but upper wheel was not turning more than 4 turns to a stop. This was the issue I described in my original post. Working now, but since piston is leaking I took it out to rebuild.

Autopilot installer pretty much told me they were done. "Worked when we left the boat". "Air must have gotten in there through the leak". Which is BS as it's under pressure and nothing is going IN. And they don't get involved in that. Hard to find good help these days. BOE electronics in Annapolis btw.

Along those lines a BIG recommendation for Horton Marine Services. Helped me deal with a generator issue and were on the ball.

 

[Captain Ralph]

Ok, You got screwed.

Your post #17 says the MSV started working ;;; and bleeding the air??
Lower helm now working?

So why did you pull the ram??

Did I miss something in Albuquerque?

 

[oscarvan]

Ok, You got screwed.

Your post #17 says the MSV started working ;;; and bleeding the air??
Lower helm now working?

So why did you pull the ram??

Did I miss something in Albuquerque?

Ram leaking. Always had a slight occasional drip but got worse while I was messing with all this. One of the ways to persuade the valves when sticking is to "lean" on the stop to increase the pressure, which I was able to do with the upper helm. Somewhere in the process the MSV woke up. But it did look like a crime scene.