The original question isn't quite complete, but I suspect he is saying the Phillips fluid is truly 5606. He doesn't say that 5606 is the required fluid in the Parker pump - I suspect it is. I wouldn't worry about the small difference in viscosity. If it were mine I would put in the Phillips fluid without worry.
There is nothing automotive that is equivalent, as what is labeled "brake fluid", at least DOT3, is a glycerine-based fluid and not remotely compatible with anything in an airplane. I would suspect that the closest thing would be Transmission or power steering fluid, which are both petroleum-based. If I
were stuck on a desert and only had ATF I would use it, but in the real world I would just bite the bullet and use 5606. Just not worth the risk and trouble using anything else.
Gary Casey
5606 is the correct fluid. The 5606F is flame retardant I think. Don't put
automotive fluid in it, these are airplanes not
automobiles, besides you
already have the correct fluid.
I know when you put the wrong fluid in it you will get real good at
rebuilding all of your hyd. components even if you don't want to.
Swaid
On Wed, Sep 25, 2013 at 7:51 AM, Joseph Czabaranek
<joeczabaranek@gmail.com>wrote:
> I have a can of Phillips 66 X/C Aviation Hydraulic Fluid that Id like to
> use in my Parker 108 series hydraulic pack. MIL-PRF-5606F states that
> viscosity should be ~15cSt at 38C. The Parker/Olidyne spec is ~35-65cSt.
> So the Phillips fluid is less viscous and is labeled not for use with
> natural rubber components.
>
> Does anyone know if this fluid is
suitable?
>
> Can someone recommend an inexpensive, automotive fluid that has proven
> effective?
>
> Much appreciated
>
> Joe Czabaranek
> 424DH
>