Hydraulic steering fluid help

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Vandeusen

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Dec 14, 2021
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Have a 1987 tiger Marine crawler lower upper Helms I do not have the screw hole on the steering columns where you can add some quick hydraulic fluid and my pressure is low. I can see when I turn the upper steering wheel I have hydraulic fluid coming down underneath dripping and when I go to the reservoir I don't know where I would add the fluid in prior to pumping up the PSI??

At this point what I need to replace the upper steering wheel gearbox? Is it that's what you call it when I take the plate off from behind the steering wheel but still outside it's nothing but decoration so what I have is a steering wheel and the steering wheel pole going through the helm into a box that has three copper tubing coming off of it the copper tubing are not leaking it seems like it's almost coming from the front side of the gearbox??

Any help or suggestions would be great
 

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That's the older 3 line Hynautic system. Most stuff for them has been recently discontinued, but you can still get the seal kits for the helm pumps. The shaft seal is a common leak point on them and not hard to replace. Information on filling and bleeding is easily available as well

For adding fluid, you release the pressure, then the plug with the schrader valve on it unscrews. You add fluid through that hole, reinstall the plug, and pump the pressure back up.

For fluid, use either the (expensive) Seastar fluid or Mil-5606 hydraulic fluid. Don't use ATF, it's thicker and will make the steering significantly stiffer.
 
rslifkin said:
That's the older 3 line Hynautic system. Most stuff for them has been recently discontinued, but you can still get the seal kits for the helm pumps. The shaft seal is a common leak point on them and not hard to replace. Information on filling and bleeding is easily available as well

For adding fluid, you release the pressure, then the plug with the schrader valve on it unscrews. You add fluid through that hole, reinstall the plug, and pump the pressure back up.

For fluid, use either the (expensive) Seastar fluid or Mil-5606 hydraulic fluid. Don't use ATF, it's thicker and will make the steering significantly stiffer.
Click to expand...
In layman's term you're telling me that I add the hydraulic fluid by unscrewing the pressure gauge and putting the fluid in through there?
 
Also is there a way to rig it so I can get to my destination or am I just going to have to fill the hydraulic oil pressurize the system and add as needed if I get to where I'm going to get the part that I need?? I'm probably 8 hours away from my destination
 
Vandeusen said:
In layman's term you're telling me that I add the hydraulic fluid by unscrewing the pressure gauge and putting the fluid in through there?
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Not the gauge, but there should be another fitting on top of the reservoir (to the right of the gauge). You can unscrew it with a big wrench or a pair of channel locks. And then it's got a schrader valve on top of that fitting (like a car tire air fitting) to re-pressurize the system.



I think the best you can do for a temporary fix is to run the system at lower pressure than normal (maybe 10 psi instead of the recommended 20 - 30). If you have 2 helms and only 1 is leaking, steer from the other helm (especially if the leak only happens when you turn the wheel). Or use an autopilot (if installed) as much as possible to reduce how much you have to move the wheel at the helm.
 
rslifkin said:
Not the gauge, but there should be another fitting on top of the reservoir (to the right of the gauge). You can unscrew it with a big wrench or a pair of channel locks. And then it's got a schrader valve on top of that fitting (like a car tire air fitting) to re-pressurize the system.



I think the best you can do for a temporary fix is to run the system at lower pressure than normal (maybe 10 psi instead of the recommended 20 - 30). If you have 2 helms and only 1 is leaking, steer from the other helm (especially if the leak only happens when you turn the wheel). Or use an autopilot (if installed) as much as possible to reduce how much you have to move the wheel at the helm.
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So the only thing else on top is was seen in the picture which is also the spot that you would pump the air pressure back into with an air pump. I did notice yesterday when this started even driving from the lower helm still had the upper Helm dripping right now my PSI is about 12 but I don't see any more hydraulic fluid in the sight glass so I need to put hydraulic fluid in to the full line and then you say keep the pressure about 10 psi??
 

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Vandeusen said:
So the only thing else on top is was seen in the picture which is also the spot that you would pump the air pressure back into with an air pump
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Yes, that's the fitting I'm talking about. If you grab the big hex part of that fitting, the whole thing unscrews and leaves you an opening to add fluid through.
 
Okay so just crack that open add the hydraulic fluid close it and pressurize it till about 10 psi? Is that just to not let the upper Helm have enough pressure for it to leak out up there?

One more question I'm trying to turn the Schrader system should it be turning counterclockwise to come off? I know the mechanics in February had it off but I sure can't seem to take the darn thing off I even released the rest of the pressure that was in the system taking the pressure was stopping me
 
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Yes, it should unscrew counterclockwise like you'd expect. There's an o-ring on the fitting, so it may just be a little bit stuck.



Pressure-wise, you may have to experiment to see what's enough pressure to keep the upper helm working (if you need to use it), but not so much that it leaks too quickly. With a leak in the upper helm, too little pressure won't push fluid up there from the reservoir, so the helm will get air in it and stop pumping.
 
I swear the mechanic that added hydraulic fluid back in February must have been Clark Kent or maybe it's the fact that I'm a lefty and I really can't get arm strength to bust that nut loose as if I was right-handed it would probably have been more of a piece of cake it's just where that canister is located is very difficult for me I just tried to spray some WD on it I don't know how much good that will do but I'll keep working on it thank you
 
If you are afraid of breaking something, you can remove the pressure gauge and fill it there, just a smaller opening.
 
Remember that after you fill the resevoir you need to re pressurize the system, about 35 pounds of air will do it.

Then, if you have lost all your fluid go to the upper station and make 25 slow complete turns of the wheel in one direction, then 25 slow turns in the other direction. You should hit a stop. Recheck the fluid level and top off as needed, add air and away you go.

You can pm me and I will send you the exact instructions, i have the manual on the boat.

pete
 
Pete Meisinger said:
Remember that after you fill the resevoir you need to re pressurize the system, about 35 pounds of air will do it.

Then, if you have lost all your fluid go to the upper station and make 25 slow complete turns of the wheel in one direction, then 25 slow turns in the other direction. You should hit a stop. Recheck the fluid level and top off as needed, add air and away you go.

You can pm me and I will send you the exact instructions, i have the manual on the boat.

pete
Click to expand...


I recall it's closer to 60 turns each way and you need to open the bleeders first.
 
Mischief Managed said:
I recall it's closer to 60 turns each way and you need to open the bleeders first.
Click to expand...


Where would you find the bleeders and is it a bleeder per helm?

I have a bad memory but I thought when they added the fluid back in February they just did the Turning of the wheel..
 
Look between the reservoir and the steering ram. On mine, the valves are built into the bottom of the reservoir, but yours has a separate unit. Opening them up just allows the fluid to bypass the ram and go back to the reservoir so it chases any air back into the tank, works well, it's not like bleeding brakes or something where fluid comes out along with air.
 
All good info from others. I want to add a bit more.

It looks like you have near zero pressure on the reservoir at this point. Once you re-fill and re-pressurize you'll have enough pressure that unscrewing the fill cap or the gauge to add more fluid could result in an unpleasant surprise. Depress the valve stem on the bicycle type air valve to de-presurize before unscrewing the cap.

The cap seals with an O-ring. If the mechanic over tightened it's probably time for a new O-ring.

The relief valves may be near the ram or at the bottom of the reservoir.

I've attached a copy of a Hynautics manual. There are minor differences among the various Hynautic systems. I would be too take Pete up on his offer of a manual. Mine or his may match your system. Either should provide good info on filling, pressurizing and bleeding the system.

While Dometic has discontinued Hynautic the system is mostly rebuildable by a decent hydraulic shop or yourself if comfortable with hydraulics.
 

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Vandeusen said:
So the only thing else on top is was seen in the picture which is also the spot that you would pump the air pressure back into with an air pump. I did notice yesterday when this started even driving from the lower helm still had the upper Helm dripping right now my PSI is about 12 but I don't see any more hydraulic fluid in the sight glass so I need to put hydraulic fluid in to the full line and then you say keep the pressure about 10 psi??
Click to expand...


I have the same unit on my trawler. It calls for 25-30 PSI. I got the pump rebuild kit from Defender.
 
Vandeusen said:
Where would you find the bleeders and is it a bleeder per helm?

I have a bad memory but I thought when they added the fluid back in February they just did the Turning of the wheel..
Click to expand...


Mine are right next to the steering ram.
 
Thank you everyone I made it to Daytona using my twin screw for steering minimizing touching the steering wheel. I reviewed the manuals and see if I can figure it out again thank you for all the replies
 
I have an H-42/K-2, with a minor leak in the steering ram. I'm pretty sure there's still fluid in the reservoir, and the steering still works fine.

So I should be able to depressurize the reservoir, unscrew the cap/schrader valve, add fluid, put the cap back on and re-pressurize without any bleeding? Or will relieving the pressure tend to allow fluid to drain out and air into the lines?

The reservoir has a minimum level mark, but how high should I fill it? It obviously needs some air space at the top.
 
merlinj79 said:
I have an H-42/K-2, with a minor leak in the steering ram. I'm pretty sure there's still fluid in the reservoir, and the steering still works fine.

So I should be able to depressurize the reservoir, unscrew the cap/schrader valve, add fluid, put the cap back on and re-pressurize without any bleeding? Or will relieving the pressure tend to allow fluid to drain out and air into the lines?

The reservoir has a minimum level mark, but how high should I fill it? It obviously needs some air space at the top.
Click to expand...
Read the manual in Post #16 for the answers to your questions. I do suggest putting a new 'O' ring on the cap.
 
SIBERNUT said:
So Mil 5606 fluid is a less expensive replacement for
SS fluid ?
Click to expand...
Yes, Mil 5606 hydraulic fluid is listed by Hynautic as being an acceptable fluid for their systems. Last time I bought some it was about $12/qt from Aviation Spruce. Much cheaper than the Seastar fluid. Biggest difference is that it's red instead of almost clear.
 
Portage_Bay said:
Read the manual in Post #16 for the answers to your questions. I do suggest putting a new 'O' ring on the cap.
Click to expand...

The manual didn't seem to address a simple refill. Per rslifkin's post, I refilled the res without attempting any bleeding. I didn't observe a level increase when the pressure was released so I assume the fluid didn't drain out of the upper lines. Steering works fine afterwards.

The fill port cap was a 1" hex, I used a crescent wrench but in case the cap is stuck you might want a box end. Mine was a tad stiff but not scary tight.

I replaced the O-ring, it's a #14, readily available online or at the auto parts store, I grabbed several.

Test your bicycle pump before you start, to make sure it can reach and that you have room to pump it. Depends on your specific installation. I brought two bike pumps, and a portable shop compressor just in case. Pressure is holding one day later.
 
I used a cheap Taylor made pump designed for their fenders. It essentially a rebranded pump I use at home to pump up the grandkids balls. It works well even though it is a stretch to reach.
 
Oh yeah, the fluid already in my system is yellow, and there was a bottle of generic steering fluid on the boat, also yellow, which I used. It's ISO 15 but doesn't say anything about mil 5606. Any idea if that's the wrong stuff?
 
dhays said:
I used a cheap Taylor made pump designed for their fenders. It essentially a rebranded pump I use at home to pump up the grandkids balls. It works well even though it is a stretch to reach.
Click to expand...

Yeah I'll get something like that, so my good bike pump can come home. It's easy to pump to 30-40 psi.
 
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