Grove Brake Fluid

[Skippydiesel]

I am in need of the brains trust advice;

My new, aircraft comes fitted with Grove brakes. Grove web page advises (after much superfluous information) to use MIL PRF-087257 hydraulic fluid in their systems. My old aircraft used DOT 4 automotive - easy find and relatively cheap. 

What would your recommendation/suggestions be??

Aircraft located in Australia

[GordonTurner]

SenSyn 87257 is compatible with all systems designed to operate with Milspec MIL-PRF-5606, MIL-PRF-6083, MIL-PRF-83282, and MIL-PRF-46170 fluids.

[Skippydiesel]

SenSyn 87257 is compatible with all systems designed to operate with Milspec MIL-PRF-5606, MIL-PRF-6083, MIL-PRF-83282, and MIL-PRF-46170 fluids.

Thanks Gordon; Unfortunately cant find a supplier of this product in Australia (when I Google it)


Our main oil companies are Shell, Mobil, Ampol & BP

[GordonTurner]

My interpretation is its a high temperature member of the 5606 family. I personally would just use 5606.

[Scott Todd]

I would be interested in finding a good reason to NOT use the automotive variants instead of whatever everyone else is doing. Millions of cars driving all over the planet for the last 100 years can't be completely wrong.

[GordonTurner]

In many cases the seals in units designed for 5606 (family) are completely intolerant of the automotive brake fluids, so only make this conversion very carefully.

[N190YX]

I would be interested in finding a good reason to NOT use the automotive variants instead of whatever everyone else is doing. Millions of cars driving all over the planet for the last 100 years can't be completely wrong.

To be blunt - automotive fluids, hardware, equipment, etc. are simply not necessarily applicable to aircraft. For example, aircraft brakes use different seals, O-Rings and hose materials than automobiles and these materials are not compatible with automotive brake fluid. Tolerance of high temperatures may also be a concern, do you have the education, experience and knowledge to determine that?

Other examples include wiring, aircraft wire is different than automotive and other wire because the insulation material does not produce toxic fumes during an electrical fire, and only aircraft wire should be installed on an airplane. Only aircraft hardware (nuts, bolts, etc.) should be installed on an airplane, no hardware store hardware. Aircraft hardware has specific corrosion, shear, tension strength and so on as called for, and and using the correct AN and/or MS designation insures the hardware is suitable for the application on an aircraft.

Being further blunt, if you have the attitude you do not want to use aircraft quality materials, including the correct materials specified for the components to be installed on your airplane, you should not be constructing an airplane. You need the attitude that your airplane will be as good as it can be, as correct and as airworthy as it can be, which it can only be if specified and aircraft quality materials are used. If you want to be creative and go off the beaten path, do it with non-airworthy related items such as cockpit vents, paint scheme, avionics installation, things that do not affect the structural integrity and operational reliability of the airplane.

[GraemeSmith]

A problem with older (time in service) Automotive fluid is that it has absorbed quite a bit of water into its molecular structure. It is thus prone to freezing at altitude.

And as others have noted - automotive fluid dissolves aviation seals - the black goo is almost impossible to effectively clean up and you end up replacing everything.

I also agree with the last paragraph in the post before mine. .

[Scott Todd]

11 years of college with degrees in Electronics, Aerospace, and Mechanical Engineering probably does not qualify me to look at a spec sheet for fluids or seals. So my 3 airplanes are all built to standard Aerospace practices and use aviation grade brake fluid. I haven't stayed in a Holiday Inn Express lately but I am retired from Pratt&Whitney where I was a design Engineer on Jet and Rocket Engines.

I built my first airplane in South Florida. I very clearly remember EAA members and other builders rebuilding master cylinders with different O-rings to be able to use automotive fluid. I kept mine stock and used Aviation fluid.

My post was a bit tongue and cheek as the OP lives in Australia and appears to have limited access to the fancy brake fluid that people think they MUST use in airplanes. But I bet he has access to different O rings.

[GordonTurner]

As long as you do your research, use whatever you determine best, and yes, price is a quality to consider along with all others. Don’t get too far into the “aviation quality only” mantra, but it’s usually a good idea to at least consider the knowledge that comes before you.

In the end, experiment and learn. Or learn and experiment.