Baystar hydraulic fluid

[rockknocker]

I'm a little low on my baystar hydraulic steering. What other fluid can I use instead of the baystar type? I don't have time to order it. I heard automatic transmission fluid? Any help would be appreciated.

[Redhawk]

I would imagine you could use off-the-shelf hydraulic fluid. ATF is used in some power steering systems like the OBS Fords, but it is very damaging to any exposed rubber so only works in a few systems. It also shouldn't be combined with hydraulic fluid, so you would need to flush the whole system and at that point it's cheaper to spend the $7 on a quart of hydro.

[JDB]

I think I read something like MIL-H-5606(version) is aviation hydraulic fluid and is suitable for all systems containing rubber compounds... I think the latest version is G (but I'm not an aviation logistics or aviation maintenance person).

[Tom C]

Do not use ATF. Straight from the horse's mouth:

SeaStar Fluid, P/N HA5430 (1 quart), HA5440 (1 gallon). The following brands are acceptable: Chevron® Aviation Hydraulic Fluid A, Esso® Univis N15 or J13, Mobil® Aero HFA, Petro Canada Harmony HV115 (in Canada only), Shell® Aero Fluid #41, Texaco® HO15 and other fluids meeting MIL SPEC H-5606-G.

Automatic transmission fluid (Dexron II®) may be used in an emergency. Never use brake fluid. Any non-approved fluid may cause irreparable damage, loss of steering, and cancellation of warranty.

[davidsea]

  This question came up a while ago, but I can't find it in search.
  The earlier info quoted above by Tom C is what I went by when I installed my Baystar ,and I believe it's still functionally valid.  The more recent info packed with the kits basically says no ATF, brake fluid, etc. as before , but use ONLY the Dometic fluid for Seastar/Baystar - no substitutes.
   I'm very suspicious that this is profit-driven advice. I find it hard to believe that the fluid requirement changes and the product doesn't.  In any case, I don't believe that an aviation fluid - previously OK'd by Dometic - that is approved for use in thousands of different airplanes, from vintage to jets, is in any way inferior to something private-labeled for Dometic.  The hot/cold cycles and substantially higher pressures involved in air use, as well as the potential liability for failure, make it likely that this spec is about as good as mineral-based hydraulic fluid gets.
   At Historic Flight, 5606 was the only fluid for 15 different aircraft, from a Waco biplane to a Citation BizJet.  We transitioned from Phillips X/C MIL H-5606A to Aero Shell 41 MIL PRF-5606H a few years ago, but the differences for boat steering would be zero - any MIL-spec 5606 would be just fine.  The other big advantage to the aero fluid is that it's dyed red, to make even small seepage easy to spot.
   The reason I mention all this is that the Dometic stuff is $27/qt. and  Uflex is $32/qt. at West Marine, while the Phillips X/C is $11, and the Aero Shell is $11.25 online.  Gallons may be cheaper.  Google it for lowest price, Amazon not competitive with online vendors like Aircraft Spruce & Supply, Pilots HQ, or Airplane Oil .  Your friendly local airport mechanic or pilot shop probably has it in stock.
   

[Tom C]

Dometic/SeaStar, like a lot of manufacturers, is forever up against customers who don't follow the instructions, then complain about the product after it malfunctions. They are not trying to make money on their fluid, they are trying to protect their reputation.

Here is what a Dometic rep said about their fluid:

SeaStar Fluid is a clear pale yellow and begins with Mil-Spec 5606 Aircraft hydraulic fluid then additives. It has viscosity of about 14, not ISO 32, and way less than the 80 viscosity of ATF. These result in greater steering effort. It is clear colored, so if contamination occurs the color pink, orange, red, brown, or black can determine worsening conditions of rust. Also leaks won't stain like ATF.

[Tom C]

I've always been amazed when a boater invests $10,000 in a new outboard, then does not want to spend a couple hundred extra for a good stainless steel propeller. Similarly, if one has invested $1,000 in a hydraulic steering system, why on earth would one put it at risk trying to save a few bucks on fluid?

I pay $23/quart at the West Marine directly across the street from my shop, for SeaStar Hydraulic Steering Fluid. I could drive to Boeing Field, Renton, or Paine Field, and buy some aviation fluid. But I'd spend more in gas than I save. No thanks.

[JDB]

Life and unexpected expenses... Rebuilt clutch check, pilot bearing damage and subsequent input shaft destruction... 7,000 $ not in the budget for maintenance... The money/savings has to come from somewhere and right now that budget cut is stainless prop, sometimes it just happens that way.  Plus, why pay more for the exact same rated item just because it's not the name brand.  No, not trying to flame or get aggressive, just thoughts.   Sometimes name means a lot, especially when it comes to proprietary products/services, but hydraulic fluid is a regular maintenance item (class III POL).

[DevMah]

I've always been amazed when a boater invests $10,000 in a new outboard, then does want to spend a couple hundred extra for a good stainless steel propeller. Similarly, if one has invested $1,000 in a hydraulic steering system, why on earth would one put it at risk trying to save a few bucks on fluid?

I pay $23/quart at the West Marine directly across the street from my shop, for SeaStar Hydraulic Steering Fluid. I could drive to Boeing Field, Renton, or Paine Field, and buy some aviation fluid. But I'd spend more in gas than I save. No thanks.

LOL

Deja Vu ..

I see this way to often ...

Guy spends a fortune on electronics, but then spends a few hundred on install and uses offshore junk (wire, fuses, panels).

Then complains that the electronic manufacture makes junk  when they have issue...

Never gets old..

Pay now or pay double later...

The advice I offer is do it right the first time or wait save the $$ and to do it right.

Dev

[AP]

I just recently replaced my lines and therefore all new fluid.  I went with SeaStar branded fluid. 

I've obviously heard of people using other things, primarily ATF, with no problems but was scared off by the SeaStar warning.

Shortly after doing this, I was at LFS, which is a generally a well-stocked and respected store.  Right next to the SeaStar fluid was Peak 50/50 pre-diluted antifreeze with this sign.  It was 1/3 the cost of the SeaStar fluid. I couldn't find it confirmed anywhere. 

[Tom C]

Hynautic steering systems are not the same as SeaStar or BayStar systems. Do not be confused!

Remember the corporate conglomerate that owns the brands Hynautic, SeaStar, BayStar, et el., is Dometic. The previous owner was SeaStar, formerly known (in the marine division) as Teleflex.

Yes, it is very confusing, but do NOT use Hynautic fluid in a BayStar system, and vice versa.

[Fisherdv]

The OP said he didn't have time to order the OEM fluid, not that he couldn't afford it.

[Tom C]

Correct, but there are many others reading this thread, and it is always a good idea to squelch misinformation.

[Tom C]

I just checked. Sacramento West Marine has 53 quarts in stock. I am sure there are another dozen places in the Sacramento area that stock the fluid.

[ak-angler]

Dometic/SeaStar, like a lot of manufacturers, is forever up against customers who don't follow the instructions, then complain about the product after it malfunctions. They are not trying to make money on their fluid, they are trying to protect their reputation.

Here is what a Dometic rep said about their fluid:

SeaStar Fluid is a clear pale yellow and begins with Mil-Spec 5606 Aircraft hydraulic fluid then additives. It has viscosity of about 14, not ISO 32, and way less than the 80 viscosity of ATF. These result in greater steering effort. It is clear colored, so if contamination occurs the color pink, orange, red, brown, or black can determine worsening conditions of rust. Also leaks won't stain like ATF.

100% BS

[ak-angler]

Dometic/Seastar doesnt make hydraulic fluid. You can get the same thing from actual manufacturers for less than a quarter the cost.