Best Hydraulic fluid for Bow Thruster

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Arthurc

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Sep 24, 2016
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752
Location
USA
Vessel Name
Sea Bear
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Kadey-Krogen 54
I just had some modifications made to my hydraulic tank for my bow Thruster and the company that did the work didn’t refill the tank or keep the old cap that had what was in the tank before written on it.
What would be the best hydraulic fluid to refill with considering there will still be some of the old stuff in there? I do remember it said non-foaming (which I thought was a given for all hydraulic fluids).
If it’s a major issue to mix I may have a picture somewhere in my archives.
Thoughts?
Arthur
 
NOt having one of these but having worked on industrial hydraulic systems I would go back to the thruster mfgr. and ask them. If you just go by opinions here you maybe won't get a bad oil but may not get the best one.

It would also help if you said what you actually had. There may be someone here that has the same mfgr unit. As it is now everyone is guessing.

I would also go back to the shop that did your work for you and have a wee discussion as that sounds sloppy to me. At the very least they should have told you if there was no indication of what was installed so they were leery of just putting something in.
 
I’m certainly going to stop by the shop Monday and have a chat with them.
I’ll look at the exact model of Thruster when I get up to the boat later today. I wasn’t sure if there was a standard hydraulic oil for thrusters. Many of these trawler systems are still new to me...

AC
 
Here’s what my Naiad manual says

IMG_0293.jpg
 
No markings on my Thruster (can only see the vickers controller/solenoids) but found the old picture that says “SAE 10w 90-180 non foaming”

Does that make sense to anyone?
 
Hydraulic oil is now all based on ISO grades. 32, 46, 64, etc are examples. The lower the number the lighter weight. I run ISO 32 in our system powering thrusters, stabilizers, windlass, etc.

It's a new-to-you boat, right? If so, and if you don't have a good maintenance history, it might be worth draining and replacing with all new oil.

Who makes the thrusters? Do they have a recommendations?
 
Yes, new boat to me.
It’s a westmar I believe.

Draining and replacing sounds like the right call. How much of a pain is it to do, I’m assuming you need to bleed the system as well?
 
No markings on my Thruster (can only see the vickers controller/solenoids) but found the old picture that says “SAE 10w 90-180 non foaming”

Does that make sense to anyone?
It makes sense if it's gear oil. It's possible that you're looking at two different things. The SAE10w-90 is probably gear oil for the pinion gear that's located in the tunnel and has the props attatched to it. There should be a small remote mounted reservoir with a fill tube to the gear. That's a separate system from the hydraulic motor that's driving it.

That system will use hydraulic oil, and I'm guessing it's in a reservoir tank in the engine room. There should be a sight tube to show level on the tank, and a quart or two is pretty incidental in the total oil fill. The hydraulic system will probably have a filter in the system somewhere, if you drain the system, you should probably change the filter. If you change the oil, you'll have to run the system through a purge sequence that should be detailed in your Wesmar manual. If you don't have the manual, call Wesmar support (425-481-2296) and get the information from them, They're helpful in support.

FWIW the hydraulic oil in my Wesmar stabilizer system is ISO46. That's no guarantee that yours will be the same ISO rating. Hydraulic oil is by default non-foaming, the ISO # is what you're looking for.
 
Unfortunately I think the bow Thruster is original equipment with the boat so I don’t think a manual is going to happen, also I can’t see any gear oil filler, it actually looks like the hydraulic lines run right into the tube. I took my best shot at a picture.
I’ll look for a filter and will likely just drain and refill but recommendations on what to refill with would be appreciated.
 

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It makes sense if it's gear oil. It's possible that you're looking at two different things. The SAE10w-90 is probably gear oil for the pinion gear that's located in the tunnel and has the props attatched to it. There should be a small remote mounted reservoir with a fill tube to the gear. That's a separate system from the hydraulic motor that's driving it.

That system will use hydraulic oil, and I'm guessing it's in a reservoir tank in the engine room. There should be a sight tube to show level on the tank, and a quart or two is pretty incidental in the total oil fill. The hydraulic system will probably have a filter in the system somewhere, if you drain the system, you should probably change the filter. If you change the oil, you'll have to run the system through a purge sequence that should be detailed in your Wesmar manual. If you don't have the manual, call Wesmar support (425-481-2296) and get the information from them, They're helpful in support.

FWIW the hydraulic oil in my Wesmar stabilizer system is ISO46. That's no guarantee that yours will be the same ISO rating. Hydraulic oil is by default non-foaming, the ISO # is what you're looking for.

Real good point here. I had assumed you were talking about the hydraulic oil which I still think is correct since it was in the context of your hydraulic reservoir being worked on. The thruster gear box will also contain gear oil. Yours might be totally self contained. My ABT thruster gear oil is as Maerin describes with small hose coming out and connected to a little reservoir bottle.

You said you found something that read "SAE 10w 90-180 non foaming". That's not "SAE 10W-90. I'm guessing it's SAE 10W which is now known as ISO32, and I'm not sure what the 90-180 is. Maybe an operating temp range?

Just call Wesmar. They are right up the road.
 
Yes, new boat to me.
It’s a westmar I believe.

Draining and replacing sounds like the right call. How much of a pain is it to do, I’m assuming you need to bleed the system as well?

Wesmar is located in Seattle. Get a few pictures and numbers and go see them for advice. My Wesmar stabilizers use a PTO mounted Vickers pump. The tank has a filter and likely yours does too.

Write everything down and while you're at it beat up on your mechanic. If he's a Hatton guy they'll not like it either.
 
Yes it was Hatton, Craig is great but the company quality is seriously going down hill. There is a laundry list of things they did wrong or shoddy. Just fixed the wiring they did last night with the help of TwistedTree.
 
If you think the unit is Wesmar then talk to them.
As T.T. said the crossover is likely ISO32. It could also be ISO 46
Either should be readily available in 5 gal. pails.
Take a photo and copy mfgr names, valve and pump numbers so they can see what you have.
If you can get at it also the hydr. motor that drives the actual propellor.
 
Wesmar said to go with ISO46, thanks for the help everyone.
 
ISO 46 is the correct weight to use. Make sure you use a name brand oil. Its cheap insurance. the crap that they sell in the "big box" stores (ie. Sam's Club, etc) will fail when you most need it to work. All multi viscosity oils will strip back to a straight viscosity sometime during their life. A cheap oil will strip back in a matter of hours and thin out and bypass inside your hydraulic motor, as well as causing premature bearing failure. A name brand (Mobile, Shell, etc) will last for years.
John
 
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