Steering leak

[jrhaszard]

I am readying myself to track down a hydraulic leak in my 1980 FBC. I have to think about it for a few days prior to getting down to tracking the leak in all the cubby holes, so I thought I would put a few questions out for some info from those who know more than me. What I think I know: There is a reservoir/accumulator next to the tillers with a pressure gauge. 30-40 psi I believe; Hynautics system with a Simrad AP 11 autopilot, so there is a potentiometer for rudder position indication; some number of hoses run forward; Steering wheel has a helm "pump" ? with a manifold which has three outlets, each with a hose. Several years ago, I had Capt. Pat's rudders installed at Tiffany yachts in Burgess,Va. and they beat the old ones out. They also busted the pressure gauge off the reservoir and of course denied doing that so I had to repair it myself. It required lying on my belly to fill and repressurize the reservoir, then climbing up to rotate the wheel each way about twenty times, then bleeding the hoses, then repeating.

Since then I have acquired stitches along my sternum and lying on my belly is a bit painful. Any info I have that will help me will cut that time.

What I don't know: Where do the three hoses from the helm go? ; how does the autopilot influence and power the steering system?; is the helm a pump?; what is the hose routing from the rudder actuator forward? I admit to being a little lazy in tracing down the hose leak, but I don't see any evidence of a leak in the rear of the boat. I am using MIL-H-5606.

Thanks, as always John

[CaptPatrick]

John,

Why do suspect a leak? A leak will usually leave a tale tale sign near the point of the leak. Sometimes, however, the leak will travel down the outside of the line until it leaves a drop at the lowest point, but sooner or later there will be hydraulic fluid somewhere. Sure it's not air in the line? Low air pressure in the resorvalve?

[jrhaszard]

Patrick, I repaired the reservoir and replaced the steering actuator three or four years ago and bled the system. All worked well until the other day when I lost steering and had to divert to a marina down the bay where we repressurized and went on our way. When we got back to my dock, steering had gone out again. I added about a pint and a half of fluid and repressurized but did not bleed it. have not been out since. Pressure is now 22 psi. Is it possible that there was an air bubble in the system all along that worked its way down to the reservoir finally? Would that cause the pressure to drop along with the fluid level? I hope that is the case but doubt it. This boat has had little use this year due to nesting ospreys at my dock. I didn't want to disturb them and the mother raises holy hell whenever anyone goes near her nest. Can't take screaming females. BTW I hope to make it to the Bertram display/get together on the 5 of November.

[CaptPatrick]

A bubble wouldn't account for a pint & a half of loss... There's gotta' be a puddle somewhere, likely on the bridge or transom bilge. If the transom bilge it'll be in the center. If there's water there, the oil will be floating on top.

[Bruce]

Hey John, how you been?

Serious doubt you had a air bubble with having to add a pint or more of fluid. Besides its a closed pressurized system, an airbubble won't drop the pressure. Air just makes system either noisy, hard to steer or spongy.

The 3 lines in the system are port, stb, and the third can be called a return, feeder to the resvalve. Hynautic helms are marked and the helm is a pump. The tank is there to keep fluid at the helm as it does not store fluid like say a sea star helm does. The auto pilot depending on the exact pump would install after the check valve block and just acts like another helm. The check valve prevents the wheel from rotating when the AP is running. You also back off the ck valve nuts when bleeding. This allows you to continually have fluid passing thru the system while turning the wheel without stops and carrying the air to the tank where it stays.

Follow your lines by the higest point till you see fluid and there is your leak. If you know for sure the tank level was okay before and you added fluid to bring it up to the same level, it leaked out.

If your tank had a bad air valve, you still wouldn't have to add fluid.

I did have a rare occurance on a 3 station hynautic nose bleed tower where no one went and the helm seals leaked just enough at a time to have the hot sun bake off the oil residue and the system would lose pressure and fluid over time.

[jrhaszard]

Then I must not know how to correctly bleed the system. I will trace the lines and look for the leak to see what I have to replace. I thought you had to crack each helm fitting one at a time allowing air (and fluid) to escape, followed by refilling and repressurizing and repeating the process. I will have to locaate the autopilot and its fittings.

Hope to see you in Ft. lauderdale.

[CaptPatrick]

I hope to make it to the Bertram display/get together on the 5 of November

John,

We look forward to it!

[jrhaszard]

Well, today I found and identified the check valve with its' two pinned bypass nuts, and the autopilot pump and motor. The check valve is just below the reservoir and the autopilot pump is just forward of that bolted to some structure below deck. There was no leaking under the helm , around the reservoir, the autopilot pump or the rudder servo. I looked up under the flybridge and saw the autopilot electronic control unit and the hoses that come from the helm and go down the right side of the ship back aft under the deck. Then, I looked under the deck as much as I could and found no evidence of a leak. I increaseed the pressure on the reservoir from around 23 to around 43 psi and turned the wheel stop to stop thirty times. I rechecked the pressure and it remained at 43 psi. I will check again tomerrow.

I am afraid the leak is in a hose that will require removing the starboard deck. Something I am loath to do. It would seem to me if there was a compromised hose, the leak would be of greater magnitude. Could it be something I am missing? Happens at the worst time. The fish are biting!

Another thing. With a twin engine I am OK if the steering goes out unless I lose an engine, (if I did go out to try the steering again). I have Capt. Pat's rudders and that increases the single engine Vmcw. What if I lose steering, refill and repressurize the reservoir and use the autopilot to return? Would that work? Or would I lose both?

For a true mechanic, this is a simple system. For me, with no knowledge, it takes a little research to figure things out. The C-5 was a hydraulic airplane. We carried those white absorbent pads ( BIG ones) by the bales. When using the hydraulics on the ground to kneel or open the doors/ramps, it sounds like mastodons in love.

[mike ohlstein]

Have you tried putting an oil diaper under the ram and checking for spotting?

It's always the ram…….

[jrhaszard]

I could find no evidence of a leak there and I installed a new one several years ago but I will definately try that. I hope it is the ram because it is accessable, unlike some of the hoses. Thanks!

[Navatech]

Personally I don't like leaving replaced cables, hoses and so forth but if you have to replace the hoses and you're loath to open up your deck it might be possible to pull new hoses without opening up the deck...

As another option, you could just put a few hatches in strategic locations in order to pull the new hoses properly...

[FWHaas3]

We had a hose break under the deck on the starboard side that we could not access without tearing up the deck. Disconnected the hose at the auto pilot and the rear accumulator, and ran new a new hose under the center of the deck that is totally accessible. Since the old hose is apparently strapped along its route under the deck, for the time being, we left it in place.

Fred Haas

[jrhaszard]

I replenished the reservoir and the air pressure on the accumulator and drove out to the bay usinng both the autopilot and the wheel. When I returned, I had no fluid loss and full pressure. Go figure. I guess I'll just keep an eye on it. Thanks for all the suggestions.