Hynautic bleeding

I changed my o ring on my fly bridge steering. All I did was replace woodruff and o ring and then fill at the upper pump until over flow. Moved the wheel both sides and then capped. Done.

I'm not a hydraulic expert, but the point is to get the air out - that's why you bleed from the lowest point on an intial installation.

The air will mostly add a mushy feel (it compresses, the fluid does not), and if you don't introduce much air, you might be able to push it out at the upper helm. If it still feels mushy then you might want to bleed the entire system (yeah, I know)

check to see if your system has an accumulator (aluminum tank about 4" in diameter and 7" high with an air connection on top) if it does, just add a little fluid at the port near your upper helm. there will be a pressure gauge on the accumulator. If the gauge only shows a couple of psi, get a bicycle pump and pump it up a little and your problem will be solved.
John

This is strictly from my recollections. The reservoir or a block near the cylinder has hex nuts. Loosening the hex nuts and turning the wheel bypasses the cylinder and allows the helm pump to circulate the oil in a loop. Air bubbles accumulate in the reservoir. To determine which way to turn the wheel loosen one of the nuts and rotate the steering wheel. If you are turning in the right direction to bleed the cylinder shouldn't move. Purge the line in that direction, tighten nut and loosen other and turn steering wheel the other way. Teleflex Capilano works similarly using a device called a Uniflow valve. You shouldn't have to purge the cylinder unless the system was extremely low on fluid in which case there may have been some air forced down that far. I wouldn't advise vigorous turning as you will emulsify the air in the oil and it will not bubble out of the reservoir as easily. The further the helm from the resevoir the more turns you need to purge the system. Set it up, crack a cold one and take your time

I copy/pasted the bleeding instructions from a circa 1980s Hynautic manual for the systems that have the pressurized resevoir (accumulator). Hope this helps.


1. Loosen two purging screws. Back off by hand, counterclockwise, until they stop. DO NOT FORCE

2. Fill reservoir 3/4 full

3. Slowly pressurize to 35-40 psi

4. On Bridge, bleed air out of Port & Starboard lines, one at a time. Re-tighten. Check levels, re-pressurize to 35-40 psi.

5. Steps 6-9 can be accomplished (turning wheel 40 times in one directions because the two purging screws are open).

6. On Bridge, turn wheel to port, SLOWLY, 40 times, 2-3 seconds per revolution. Check levels, re-pressurize to 35-40 psi.

7. At lower helm, turn wheel to port, SLOWLY, same as #5 . Check levels, re-pressurize to 35-40 psi.

8. Return to Bridge, same procedure to starboard, SLOWLY. Check levels, re-pressurize to 35-40 psi.

9. At lower helm, same procedure to starboard, SLOWLY. Check levels, re-pressurize to 35-40 psi.

10. At steering cylinder, bleed both ends by (a) back off the socket head cap screw bleeders one turn, let air escape, tighten; OR (b) open the hose fitting connections one at a time.

11. Close the two relief valves by hand, snug with a wrench.

12. Refill reservoir, adjust pressure to 25-30 psi

13. The following fluids can be used: Hynautic Steering Fluid MCO-06 ; Dextron 3 Automatic Transmission Fluid; Aircraft Hydraulic Fluid.

I bled my steering system system recently after I replaced my relief valve which had some corrosion on it and was leaking. It wasn't too bad really. I could actually hear the air hiss as it exited the relief valve when I turned the wheel.

It's item 10 on the list that's the problem for me doing this now, no access. I'll take a chance on Blue Heron's advice. Yes, I do have the pressure tank.

Meridian,
I know it worked for me. Since the plug is at the top of the pump reservoir at the top of the entire system, the logic is that the only bleeding would need to be done from the lower helm pump to this pump. The leak I had was from the outer O-ring on the steering shaft mount, that after filling and turning the wheel slowly side to side then closing the plug.

Just be careful when removing the wheel. A rubber mallet and some PB blaster worked to get the wheel off. The Woodruff I grinded out leaving enough to see the size to match it. O-ring and Lithium grease and woodruff key from Autozone. It cost me 30 minutes of time and 14 dollars.

good luck.

(if i cracked the lower helm pump I would have serviced from the pump and bled from the Lazerette)

I wouldn't worry too much about bleeding the cylinders if you can't get to them. The pressurized accumulator will force all air to the highest point as you turn the wheel in each direction. (by the way, i design hydraulic systems for a living; have for the last 40 years)
John

John, My reservoir is at the lower helm. How does the air get expeled from the system at the upper helm?
Terry

Opening the charging valve bypasses the cylinder so that when you turn the steering wheel oil is cirulated in a loop through the reservoir. As the oil passes through the reservoir air bubbles float up into the reservoir where they stay. The reason you turn the wheel slowly is if you don't the air will become emulsified in the oil and not float up as it passes through the reservoir. Later it will separate and float to the highest point.

If you didn't lose much of your oil it is not likely the cylinder will need bleeding since it is at the lowest point but even if it does the air will tend to find its way up where you can use your charging valve bleeding procedure to remove it.

Sorry it took so long to get back as i was not near a computer. Air in a hydraulic system will always go to the highest point eventually. Unless your system ran completely dry and you had no fluid in your steering cylinders there is no need to bleed them. If your system has the pressurized reservoir (accumulator) you can fill it there or sometimes there will be a fill at the upper station. As long as you have the air connection (like a tire nozzle) get a tire pump and pump up the reservior (accumulator) to about 30 or so psi (or whatever your owners manual says) then turn your wheel back and forth. you might need to crack some lines leading to the upper station, but the air should be forced up to the highest spot with out doing anything other that loosening the fill cap at the upper station. If you do not have a pressurized reservior (with the air connection) it becomes a lot more difficult. but again unless your cylinders were empty, no air would get in them anyway. Manual pumps (that is what is attached to your steering wheel) turn too slow to cavitate or aerate the system. That means create air bubbles that move through the system.
I don't do a lot of work on pleasure boats (mostly large commercial fishing or tug boats) but I have worked on my own systems and most of the guys on my dock from 25' cuddy's to 48' Pacemakers and Posts)
John

Love it follow up is given. Thanks for sharing!

As I discussed this seal kit installation with some fellow boaters, they seem to think that the steering is noe too tight. Has anyone else had this issue?

Was the helm tight after you assembled it before reinstalling? Was it tight immediately upon reinstallation or did it tighten up later after recharging? Did you use proper fluid to recharge the system (see post #6) or maybe used heavier weight oil than was in the system previously?

It was tight when I re-installed it, same fluid. It does work but takes a lot of pressure to turn. The hard beveled ring was a real tight fit to press on the shaft. It fits into the wheel hub and the x-ring is underneath it.

It sounds like the tightness is friction from the new seals. It should ease as time goes on. That is if the installation was correct and you did not roll or twist the seal as you pushed it over the shaft.
John