Grove Brake Fluid
Posted: Fri Dec 10, 2021 7:47 pm
by 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
Re: Grove Brake Fluid
Posted: Fri Dec 10, 2021 9:21 pm
by 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.
Re: Grove Brake Fluid
Posted: Sat Dec 11, 2021 1:19 am
by Skippydiesel
GordonTurner wrote: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
Re: Grove Brake Fluid
Posted: Sat Dec 11, 2021 9:03 am
by GordonTurner
My interpretation is its a high temperature member of the 5606 family. I personally would just use 5606.
Re: Grove Brake Fluid
Posted: Sat Dec 11, 2021 9:40 am
by 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.
Re: Grove Brake Fluid
Posted: Sat Dec 11, 2021 10:41 am
by 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.
Re: Grove Brake Fluid
Posted: Mon Dec 13, 2021 3:07 pm
by N190YX
Scott Todd wrote: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.
Re: Grove Brake Fluid
Posted: Mon Dec 13, 2021 3:48 pm
by 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. .
Re: Grove Brake Fluid
Posted: Mon Dec 13, 2021 5:59 pm
by 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.
Re: Grove Brake Fluid
Posted: Mon Dec 13, 2021 11:57 pm
by 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.
Re: Grove Brake Fluid
Posted: Tue Dec 14, 2021 12:09 am
by sonex892.
Skippydiesel wrote:What would your recommendation/suggestions be??Aircraft located in Australia
Here is on in Oz. Spec sheet says this is 5606. https://www.e.com.au/product/aeroshell-fluid-41/
Re: Grove Brake Fluid
Posted: Tue Dec 14, 2021 7:47 am
by Skippydiesel
My last air craft an ATEC Zephyr powered by a Rotax 912 ULS, used very few “aviation components” in its compost/wood/fabric construction. All fasteners were of the shelf metric - high tensile & stainless steel where applicable. Brake fluid, ordinary automotive (changed every 2 years). Very nice aircraft with impeccable flying characteristics and extraordinarily cheap to run (13L/hr at 100 knots, capable of up to 120 knot cruise and a 30 knot stall).
Dedicated aviation parts/materials have their place but to suggest that nothing else will do, is just plain wrong - dont forget your Wright Brothers did not use certified aviation materials in their aircraft and look what they achieved.
Recreational aircraft do not need high cost dedicated aviation materials. As for brake systems, there is absolutely no good reason why the manufactures of aircraft brake systems (for recreation level aircraft) could not use automotive fluid compatible seals (they do in Europe).
Re: Grove Brake Fluid
Posted: Tue Dec 14, 2021 11:50 am
by Area 51%
GraemeSmith wrote: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.
Agreed…most automotive brake fluids have a great affinity for water. I ain’t buying the freezing at altitude, though. Unless -10F is different at 10,000ft than it is in a Michigan driveway in Feburary.
Automotive brake system reservoirs are not vented directly to the atmosphere, but have an accordion-like seal to take up space without allowing moisture laden air to contaminate the fluid. Given that some H2O is going to get into the system, regardless of the care taken, there must be some allowable percentage. That information is probably archived along with the Dead Sea Scrolls and Ten Commandments.
As a matter of fact, engine coolant’s freezing point goes DOWN with the introduction of water. To a certain point. Does brake fluid possibly exhibit the same characteristic? Any articles I’ve read on moisture contaminated brake fluid revolves around corrosion. Never seen a reference to “frozen fluid”.
Having said all that…my Sonex supplied master cylinder had a sticker on it reading “DOT 5 fluid only”.
Re: Grove Brake Fluid
Posted: Tue Dec 14, 2021 1:22 pm
by Scott Todd
"my Sonex supplied master cylinder had a sticker on it reading “DOT 5 fluid only”
That there is just funny 
Re: Grove Brake Fluid
Posted: Tue Dec 14, 2021 2:34 pm
by Area 51%
Scott Todd wrote:That there is just funny
Which part? Give me your email and I"ll send you a picture.
Re: Grove Brake Fluid
Posted: Tue Dec 14, 2021 3:33 pm
by Kai
No, not really.
DOT 5 (actually DOT 5.0- very important!) automotive brake fluid, is silicone based- contrary to all other automotive DOT (4.1, 5.1 etc) brake fluids, which are glycol based. It is a high end product that withstands high temperatures, has no affinity to moisture (hence does not promote corrosion and freezing), has a long service life, and does not eat aviation o-rings, gaskets, seals, and other rubber components.
I have used it for years in the Sonex hydraulic disc brake setup: works as advertised!
Thx
Re: Grove Brake Fluid
Posted: Tue Dec 14, 2021 5:38 pm
by Scott Todd
I thought it was funny because of earlier posters indicating how important it was to use only aviation grade brake fluid. I’m a supporter of alternate, and sometimes more modern, solutions. I agree with following most Aerospace standards but some of them are outdated. Its an Experimental airplane. I don’t think there is anything wrong with substitute fluids or changing the O ring seals to be more accommodating. I have not done it and don’t really care but would be curious to see what O ring material Grove uses. But as someone pointed out, I’m not qualified to understand them