Hynautic Mil spec 5606 alternative

[Jwatson]

I am having my steering arm rebuilt and would like to know some alternatives to the Hynautic 5606 steering fluid. I know Phillips 66 is compatible. Is Teleflex SeaStar Hydraulic Fluid HA-5430 a compatible alternative or Seastar HA 5430H? I can get a gallon and of Phillips 66 on amazon for $43 (including shipping). Thank you.

[Boatsb]

Seastar works. Comes in quarts and gallons.

I have no idea what the phillips 66 is .

[Jwatson]

Phillips 66 X/C 5606A Aviation Hydaulic Fluid.

[carolinacoast]

5606 is red, so when it leaks you know exactly what it is. When the flybridge Hynautic seal started leaking, my daughter pointed out, 'Dad, the boat is bleeding."
I prefer 5606 for that reason, and I don't think that seastar really saves you much.

[krush]

Regular prestone or walfart power steering fluid. Works the same. If you want it to be red, put in a little ATF.

[DCMY #92]

Power steering fluid (Dextron II) is OK for warm climates, but not for very-cold.

[piratestreasure]

Good morning everyone,Reading on this post that automotive Power steering fluid works.Is this true?

[KPTIM]

You can by the correct fluid from Sam's

Part Number, 18934

[luckydave215]

You can also get it at Aircraft Spruce and Specialty. Gallons are very reasonable and they ship...

[krush]

Good morning everyone,Reading on this post that automotive Power steering fluid works.Is this true?

It works, but it is thicker and will make steering slightly more difficult, especially if cold. ATF is also thicker than 5606.


GREAT NEWS EVERYBODY I did some research and experiment. I can't find the darn chart, but basically I found that 5606 is nearly equal to ISO 15 hydraulic fluid, which is VERY thin. It pours like water. The only ISO15 hydraulic fluid I could find was 5 gallons. But that was fine, because I needed to flush the system in two boats. I bought it here: https://petroleumservicecompany.com/...5-gallon-pail/

I flushed out all the fluid from my hatt (it probably took 2-3 gallons) and a twin outboard boat. I was using power steering fluid. The color of the ISO 15 is very light, much like the $$$$hynautic stuff. My guess is they put ISO15 in their bottles and charge $$$$.

I can report that steering is MUCH EASIER with ISO 15 fluid.

Other brands are available: https://petroleumservicecompany.com/...hydraulic-oil/

ISO 15 HVI Hydraulic Oils have a thickness that is similar to SAE 5W at operating temperature. High Viscosity Index hydraulic oils, also called Multi-Viscosity Hydraulic Fluids, are formulated to maintain their ideal viscosity, or thickness, over an extreme range of temperatures. The wider the temperature range, the higher the viscosity index number.