Hole in upper helm fill cap.

My steering has been getting progressively less responsive, so I thought I would bleed and check the fluid level of my helm wheels.

The fluid was low, so I filled it up at the upper helm. After replacing the cap I noticed a bunch of fluid leaking from the fill area of the pump. Upon closer examination I notice the fill cap has about a 3/16 hole drilled in it. I am pretty sure it wasn't manufactured that way because the hole isn't centered and on axis. It looks like it was drilled with a hand held drill. Anyway, I plugged the hole temporarily with a wood screw. I have since brought it home and tapped the hole and screwed in a nylon bolt to plug the hole.

But I want to be sure it isn't supposed to be there. Any idea what that hole could be meant to do?

Here is a photo of the plug with the screw in the hole.

In every system I'm familiar with that's not pressurized the upper helm cap is vented, the lower helm is not

Hynautic: pressurized
Seastar not
Wagner not
Capilano not

Ok, I am pretty sure mine is a Capilano system. I'll take the nylon bolt that I threaded in.

I filled the upper helm all the way, and when I turned the wheel it dumped about 1/4 cup of fluid out the vent hole. Is that normal? In other words is it not meant to be filled up all the way?

The po might have felt it needed a vent. Most helm pumps I've seen have a front and back fill. The one not in use has a plug.

No, it is not meant to be filled all the way. A small amount of space is left to allow air purging without spilling, also for temperature changes.

The pistons and the pump inside the case should be well covered but that is usually about it.

A 3/16" hole is far too large, all that is needed is 1/16" max. Just enough to allow venting.

If you noticed changing and slow steering response you may have gotten air into the system. When you filled it if there was any residual air the oil would be forced out without some expansion room.

On mine the cap is actually exposed to the weather so the vent hole is in the side of the cap, not the top. There is also a small downward angle to the vent hole.

If the system can't vent it may force oil out at a seal on the pump shaft with rising temperature.

When I replaced my old Wagner Autopilot with a Raymarine unit, I wasn't quick enough on transferring the pipes that attach to the pump, so I had to add some fluid and bleed the system. It took weeks to finally get the upper wheel to stop puking small amounts of oil out of the vent. I put a piece of tubing on the vent, led it into a yogurt container that I trapped on top of the upper helm pump, so that if it wanted to refill itself from this reservoir, it could. After a few months I put that "overflow tank" away, as it had settled down.

I'll drill a 1/16th diameter hole in the nylon bolt, making it a small vent. If it keeps spitting out fluid, I'll use the reservoir idea.

On top of all that, the steering still isn't right. It is a lot better, but I still need to bleed it some more, I just side tracked onto the spilling fluid, and the hole.

Progress is progress though.

Would it bleed any quicker if I turned the upper helm one direction, and then turned the lower helm the other alternating like that so each wheel pump is always going the same direction.

I need to find the manual for this system and review how it works.

I got tired of trying to check/fill ours through the dash hole and bought a remote fill kit part # HA 5450 like in the photo. It now filled from the top of the dash and it has a waterproof vented cap. Bonus is the added hose acts a reservoir and way easier to fill.

Check the library at the top right of the page as I posted all the manuals for the Capilano system there a few years back.

I'd tap the plug for 1/8 NPT and put in a petcock. Then you can control the vent.

I would contact the manufacturer of the steering system for advice. Mine is a Sea Star and vas a "vented" cap at the upper helm and a non-vented (solid) cap at the lower helm. Sea Star provides extensive installation, filling. bleeding, and troubleshooting advice.

https://www.jamestowndistributors.c...x+Capilano+Inboard+Hydraulic+Steering+Systems

Thanks, good information there.

It looks like the vent was installed at the wrong location. It was on the aft plug in the upper helm. That documentation shows it as being in the forward plug.

f508 said:

Thanks, good information there.

It looks like the vent was installed at the wrong location. It was on the aft plug in the upper helm. That documentation shows it as being in the forward plug.

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I have the same helm pump and the manual for it. Either plug in the upper helm MUST be vented. If you're worried about getting dirt in there you can use a sintered bronze plug. As far as fill level goes the manual states 1/2" below the threads for the cap.

Ken

Thanks!

I put a pipe to hose fitting that replaced the plug and attached a clear plastic hose about 1’ long. At the end I put an automotive fuel filter. I just look at the red ATF in the hose to check the fluid level and add a small amount as necessary. There’s no air in my system.

If it wasn’t for the lack of space above the pump I would have just filled as necessary through the fill hole w a small air space. The space can be small as the level of oil in the clear plastic hose varies very little.

Seems we’ve all dealt w this about the same way. Now and then someone will ask what’s that that little hose and filter doing there as it stickes up above my helm station a bit.

Our last trawler was a former marina queen liveaboard with a Capilano steering system. On our first cruise, fluid started leaking out the seal around the helm shaft and running down the console onto the floor. I thought the seal was gone which would have been a huge job to replace with all the hard piping that would have needed to be disturbed to remove the unit.

It's always worth reading the manuals carefully. I read the the unit is shipped with a solid fill plug but that it needs to be replaced with one with a small hole in it. I drilled a 1/32" dia hole in the plug and refilled it to the proper level (1/2" below the top).

Never leaked another drop. The PO had simply never run the boat enough to get the system pressurize to the point of pushing fluid through the shaft seal.

One way to speed the purging process is to take the boat out and use it. The rocking and rolling will help any air trapped in the lines move to the vent.

Just be confident that the steering is responding reasonable well.

I would also use a small hose attached to a hose barb installed in the vent hole. The hose should be lead to a bottle/jug so any air burped out does not blow oil all over the place. It will. No open dishes or the oil will spray when it exits. Tape the hose into place or it may flip out.

Don't ask how I know.

The mess can be avoided by doing that. Check the oil level because as the air burps out the oil level will drop as the air space is taken by oil. If it drops to far you could reintroduce air into the lines.

Once the steering improves then replace the hose and barb with the vent after checking the final level.

It is strange, I emailed Capilano and they sent me a pdf of the manual for my exact model, and it doesn't mention drilling a vent hole. The vent hole makes sense to me, but it doesn't seem to be mentioned.

I got the steering bleed and took her out for a test run and I felt that the steering was still a little soft. So I brought her back to the dock and the next time I went out to work on her the steering had firmed up on it's own. I took her out, and she is fine again.

Check the oil level again. I'll bet that it is down a bit from any pitching and rolling. The motion purged some more air. I had to do that when I did some repairs many years ago. The rocking and rolling finished the job.

Whether they , Capilano, mentions a vent hole or not a vent hole is needed. It has to be an oversight.

As suggested already a better way would be a sintered bronze vent fitting. Allows air in/out and keeps bugs and dirt out. Those things are common in pneumatic systems.
Likely on Amazon or Ebay also.

I am a bit wondering- Are there systems that do not have vented caps? Asked as the cap on both my steering stations helm and bridge, are solid. When there is suspect air in the system, I open a valve on the steering ram that connects both in and out fittings, turn the wheel side stop to side stop about 20 times, open the cap on the fly bridge, again, a solid plug, add oil till it reaches the absolute full point, recap and repeat the wheel turning then close off the valve on the steering ram. So again, if both caps are solid what is the difference between my system and these mentioned in the thread?
(While the thread deals with leakage, the cause described is the difference)
Or have I mistook my view with a different issue?

Thanks
Al

Al said:

I am a bit wondering- Are there systems that do not have vented caps?

Click to expand...

Things are often designed with the expectation that they will remain perfect. Non pressurized steering systems may do fine without a vent, whether originally intended for one or not, and then need one when seals begin to wear and let air into the system. The steering ram can become like a pump letting a little bit of air in on each stroke and then pushing it back into the hydraulic lines. Suddenly, you either need a vent or to rebuild the ram.

Guess which I chose anchored in the middle of a delivery cruise?

My Sea Star system has a vented cap in the upper helm (flybridge). You can't see a hole so I suspect it's sintered bronze like someone mentioned. I don't remember if it's shaped differently or actually labelled as "vented".

f508 said:

Would it bleed any quicker if I turned the upper helm one direction, and then turned the lower helm the other alternating like that so each wheel pump is always going the same direction.

.

Click to expand...

This is how all Hydraulic steering systems in cars are bled. Usually a few full turns both ways gets everything bled. The fill reservoir will "burp" in the process until all the crannies are filled..

Hopefully this helps.

Wow, that is a MUCH more comprehensive manual for my system than the one they sent me.

Thanks!

My Capilano system bleeds quickly.
From about 2’ fwd of the rudder/slave cyl my hydraulic hoses run fwd to the helm never going down or even level. The air bubbles go far enough fwd to reach the straight run up to the helm. Putting the helm hard over pushes the bubbles out of the cylinder and up the hose. It was a bit difficult to do but it was/is worth it. I think there is a lot of boats out there w air in their lines/hoses all the time. I was determined to have a nice responsive steering system. It paied off.

My upper helm capilano system has a vent hole.

Roger Long said:

Things are often designed with the expectation that they will remain perfect. Non pressurized steering systems may do fine without a vent, whether originally intended for one or not, and then need one when seals begin to wear and let air into the system. The steering ram can become like a pump letting a little bit of air in on each stroke and then pushing it back into the hydraulic lines. Suddenly, you either need a vent or to rebuild the ram.

Guess which I chose anchored in the middle of a delivery cruise?

Click to expand...

Ouch!

This thread is very informative. Going to check our my system next time I’m in the barn.

Try search internet for "plastic nylon vent plug gearbox" there are lots of styles and sizes available.