Mainship Hydraulic steering
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If you have answers, please help by responding to the unanswered posts.
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There isn’t one as it’s part of the hydraulic pump operated by the wheel.
To add fluid (you need to do more than vent it) get a Seastar hydraulic fluid kit which consists of a quart of fluid, a hose fitting and a piece of plastic hose. Follow the directions.
David
To add fluid (you need to do more than vent it) get a Seastar hydraulic fluid kit which consists of a quart of fluid, a hose fitting and a piece of plastic hose. Follow the directions.
David
garmstro55
Senior Member
My MS400 had the same sloppy steering, it happened gradually over a few years and wasn't very noticeable until last summer. I took a 1 quart plastic oil bottle and cut in half. Then you screw the oil filler tube to both the fill hole and the bottom of the bottle. Ideally you have another set of hands. Next pour some fluid into the bottle and have someone spin the wheel back and forth. I did something like 10 rotations each direction if I recall correctly. If there is air in the system, it will bubble up the tube and the fluid will go down. I probably had to do 20 or 25 cycles to get all the air out, so don't give up until you don't get any more bubbles. Obviously keep fluid in the bottle as it goes down. Now the steering is very responsive.
On the 390 there are two fluid ports, one at each helm. I would recommend starting with the flybridge helm, and do as described above with the seastar kit. Lots of rags. Flybridge port should be just above the wheel hub. The lower port is inside the flip-up dash, again near the helm hub.
I am not sure that you can do the same top-off with the lower helm. I would think opening that would spill at least some of the fluid above that helm and introduce air.
I expect the system was filled from the lower helm when new/empty. Then from the upper helm to make that one work and fill the rest of the system.
--Kevin
I am not sure that you can do the same top-off with the lower helm. I would think opening that would spill at least some of the fluid above that helm and introduce air.
I expect the system was filled from the lower helm when new/empty. Then from the upper helm to make that one work and fill the rest of the system.
--Kevin
garmstro55
Senior Member
Don’t remove the lower plug or you’ll drain the whole system from the flybridge down.
Dougcole
Guru
Exactly this.
Newtrawlerowner
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There should be a fill plug near the steering wheel. On my boat MS 400, its under the instrument panel.
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Newtrawlerowner
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If you have 2 helms, bleed the lower then the upper.
skipper724
Veteran Member
My tech said to never bleed from the lower helm.
Keysdisease
Guru
What garmstro55 says.
SeaStar steering like Mainship used, and Wagner, another popular and similar system, are both "vented" systems, as opposed to Hynautic which is pressurized. The fill plug in the vented systems are different on the upper and lower helms. The lower helm is non-vented, and the upper helm plug is vented. If you remove the lower helm plug all the oil in the upper helm and plumbing will drain out. Fill and bleed per instructions from the upper helm only.
SeaStar steering like Mainship used, and Wagner, another popular and similar system, are both "vented" systems, as opposed to Hynautic which is pressurized. The fill plug in the vented systems are different on the upper and lower helms. The lower helm is non-vented, and the upper helm plug is vented. If you remove the lower helm plug all the oil in the upper helm and plumbing will drain out. Fill and bleed per instructions from the upper helm only.
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Newtrawlerowner
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I can't argue with the plug style, vented or not. But I have bled my Sea Star system from the lower and upper helms.
No fluid leaked when I removed the lower helm plug to bleed the system. Sea Star never mentions it leaking in their procedure.
When I did bleed the lower helm, I got all of the air out and the lower helm worked perfectly. The upper helm still was not as responsive.
That was corrected once the upper helm was bled.
See the Sea Star procedure for dual helms here.
No fluid leaked when I removed the lower helm plug to bleed the system. Sea Star never mentions it leaking in their procedure.
When I did bleed the lower helm, I got all of the air out and the lower helm worked perfectly. The upper helm still was not as responsive.
That was corrected once the upper helm was bled.
See the Sea Star procedure for dual helms here.
rgano
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My Pilot has only the one station, and the fill plug is unvented - possibly an installation error. I check the level a couple of time a year, and going on ten years now, I rarely have to add any fluid. Before I knew better, I once filled it completely full. I immediately noted that there was a lump, lump, lump feel from the wheel as I turned it as if I was feeling every vane in the pump. I pulled some of the fluid out to give a bit of air gap in the reservoir and the lumpiness disappeared. Maybe I should have a vented cap.
Binford
Member
If your system is already filled, but you’re trying to work out any air trapped in the tubing, then fill from the upper helm, turning the upper wheel as described. When no more air is apparent up there, go downstairs and simply work the lower wheel a bunch. Any air in the tubing at the lower helm will thus be pushed out into the rest of the system. Then go back to the upper helm and work that wheel again until any further air is worked out and it won’t take any more fluid. Done.
Periodically pull the cap at the upper helm to check that the fluid is full, and top off as necessary. This will prevent the reintroduction of air into the system.
Periodically pull the cap at the upper helm to check that the fluid is full, and top off as necessary. This will prevent the reintroduction of air into the system.
Dougcole
Guru
Also, if you have lost some fluid it means it went somewhere and you have a small leak in the system. By far the most likely culprit is the cylinder, which on the 400 (probably the 390 too) is down in the laz next to the rudder stock. Look for a little oil around it, probably won’t be much.
It’s easy to remove ands can be sent off for rebuilding.
It’s easy to remove ands can be sent off for rebuilding.
ronobrien
Guru
Purging the system can be a real pain. I converted my cable steering to hydraulic and wound up buyer a purge pump kit. ($1200) but for me it was worth it. You may find someone locally that has one (marine mechanic) and get it done in under an hour.
ronobrien
Guru
I recently converted my cable system to hydraulic (2 station) and the old instructions (looked up online) were for a vented cap at the upper station but the newer instructions were for both caps UNvented.
Newtrawlerowner
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Curious who might rebuild the steering ram. Mine is leaking.
Cold Duck
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Depends on where you are but it's a simple hydraulic ram. Any good hydraulic shop should be able to reseal it.
Dougcole
Guru
This is who I used, they did a great job and turned it around quickly. They are based in Venice, so not too far from you. If I recall correctly, it was about $350.
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