Hynautic Fluid Topping Off

[dave1985]

I have no idea what fluid is in the Hynautic Steering system on my 36c that I bought last year. The system is working fine. Would using the steering fluid Teleflex sells be as good as any for topping off the system or might I end up with some mismatch problem?

Thanks for any thoughts.

 

[Pascal]

the teleflex fluid found in most marine stores is the one you need, Teleflex and Hynautics is the same thing.

in a bind, you can use regular ATF although the steering will be stiffer, but it will not damage your system

I think a while back someone posted the MIL spec for that hynautic-teleflex fluid, you can also buy it (probably cheaper) form aircraft supply places...

 

[MikeP]

MIL 5606 is the best fluid for the purpose and was originally specd by Hatt. Hynautic fluid is a MUCH more expensive fluid that is NOT better in any way and is clear instead of red. 5606 is much easier to trace leak-wise than hynautic fluid. BUT the bad point is that Dexron ATF is also red so if you have red fluid in the system, you can't tell by the color whether is is ATF (bad, though acceptable) or 5606. THe best thing to do is purge all the old fluid and refill with 5606.

 

[luckydave215]

5606

MIL 5606 is the best fluid for the purpose and was originally specd by Hatt. Hynautic fluid is a MUCH more expensive fluid that is NOT better in any way and is clear instead of red. 5606 is much easier to trace leak-wise than hynautic fluid. BUT the bad point is that Dexron ATF is also red so if you have red fluid in the system, you can't tell by the color whether is is ATF (bad, though acceptable) or 5606. THe best thing to do is purge all the old fluid and refill with 5606.

I bought a whole gallon on line for $13 from an aircraft supplier back east. Sorry, I don't remember the name of the place, but everyone in the aircraft industry has it.

 

[REBrueckner]

I sure hope nobody is going to post "Don't mix Dexron and other fluids because....."

My marine mechanic told me ten years ago his team uses Dexron II ATF, that's what I did, and I haven't touched the system since...whatever was in the system was red, and so was Dexron, that was close enough for me...

 

[Boatsb]

If it is working and needs to be topped off use the mil spec 6506 or just plain HO hydraulic. In cold weather dextron will be an issue as it thickens faster in cold weather. If it was working fine a top off of the right stuff cant hurt and would prevent the need for purging the whole system.

FWIW I replaced all the tubing and hoses on mine and filled it with HO hydraulic (the non mil spec 5606 ) and it tuns so effortlessly that I believe the PO had dextron in it to make it a bit stiffer.

I did check with the Telex Hynautic people on the tubing, hose and the fluid and they were quietly accepting the fluid as it had similar properties to the 5606.

 

[31FlyCruzr]

See the purging instructions under the tips and tricks page. Per the instructions more than 2 inches in the reservoir is acceptable. Once topped off the fluid needs to be pressurized up to the flybridge and through the lines

If you de-pressurize I think you will need to follow the instructions to get any air out of the lines.

I'd inspect the system especially the flex lines, if everything looks good I'd monitor the system pressure gage during routine inspections. Pressure is a function of temperature so small changes may be normal.

If it ain't broke.....