MIL 5606

jmbrwn · Post by **jmbrwn** » Sun Mar 13, 2005 2:02 am

Guys, where do you get your brake fluid? Can you get it at Auto Zone or such, or do you have to order it from Aircraft Spruce or Wicks?

S2D · Post by **S2D** » Sun Mar 13, 2005 3:18 am

If there is a bulk oil distributor in your area that also handles aircraft oils, chances are he also can carry 5606.
I've been buying engine oil from my distributor for years but always struggling to keep a supply of 5606 oil. finally asked him a couple days ago. and he said yup been carrying it for years!! pure stupidity on my part.
Lots cheaper that way and saves on the Hazardous freight.

jmbrwn · Post by **jmbrwn** » Sun Mar 13, 2005 11:15 am

Thanks Brian! Yes, I do have a bulk oil distributor who I buy my oil from..I didn't even think of him

Post by **GAHorn** » Mon Mar 14, 2005 4:27 pm

Be aware that Mil-H-5606 came in various and subsequent desginations of 5606-A or -B or -C etc... They're all interchangeable for purposes of our aircraft brake fluid (and for oleo struts if you have them on another Cessna.) Just don't make the mistake of mixing it with other fluids such as automotive brake fluid or "DOT" type fluids or with other aviation fluids such as "Skydrol", etc.

zero.one.victor · Post by **zero.one.victor** » Mon Mar 14, 2005 5:32 pm

Strangely enough, back in my motorcycle days (70's & 80's), the local harley shop sold "aviation brake fluid" which was popular, as it was commonly believed that it wouldn't eat your paint like the regular automotive stuff allegedly would. This aviation fluid was some sort of clear silicone-based stuff. Since I've been into flying I think I've never seen anything other than 5606 used for brakes or other hydraulic systems on light GA planes.

Eric

blueldr · Post by **blueldr** » Sun Mar 20, 2005 2:45 am

For the information and education of all you junior birdmen (Remember, I'm a real old fart.), aircraft hydraulic brake systems used to contain natural rubber in their parts. As a result, petroleum based hydraulic fluids could not be used. They used to call petroleum based hydraulic fluid "Red" fluid or AN/VVO 366.
Hydraulic brake systems used "Blue" fluid which I remember as being a vegetable based oil, soluable only in alcohol. I remember that it dried to a gummy residue around any spillage or leaks and we cleaned it up with isopropyl alcohol. During WW2 the development of synthetic rubbers allowed the natural rubber seals ane other parts to die a natural death and brought on the use of, and standardization of, petroleum based hydraulic fluid which finally became "5606". I really have no idea why they still use a non petroleum brake fluid in automotive applications. They surely can't be using any natural rubber anymore.

simatos · Post by **simatos** » Thu Mar 24, 2005 4:41 am

I called several bulk suppliers here in Canada and the 5056 is an engineering specification but none could tell me a brand name so i could go out and buy a can of the stuff. What brands do you guys use? My local cessna dealer has fluid for his own use but couldn't put me intouch with his local supplier for some reason . One supplier mentioned something called Air Shell fluid #41 but unless i can get some one to say the stuff is infact brake fluid I ain't putting in my planeG

Post by **Bruce Fenstermacher** » Thu Mar 24, 2005 2:15 pm

DO NOT PUT BRAKE FLIUD IN YOUR AIRPLANE

5606 is the MIL-spec it doesn't matter what the manufacturer calls it. If it meets the Mil-spec it's good to use.

I bought a quart a few years ago from Aircraft Spruce. The name on the can is American Oil and Supply.

HA · Post by HA » Thu Mar 24, 2005 3:30 pm

we get either Aeroshell 41 or Royco 756, they are both Mil - 5606 fluid. Used to use gallon cans from Texaco, can't remember their secret number though.

S2D · Post by **S2D** » Thu Mar 24, 2005 9:48 pm

Aeroshell Fluid 4
Mil-H-5606A (obsolete)
Code 60421

Is what is on the yellow cans I just bought.

Ones I previously had were blue cans. Can't find one at the moment to see what it said.
Just make sure somewhere on the can there is a reference to Mil-H-5606

Post by **GAHorn** » Fri Mar 25, 2005 4:11 pm

simatos wrote:I called several bulk suppliers here in Canada and the 5056 is an engineering specification but none could tell me a brand name so i could go out and buy a can of the stuff. What brands do you guys use? My local cessna dealer has fluid for his own use but couldn't put me intouch with his local supplier for some reason . One supplier mentioned something called Air Shell fluid #41 but unless i can get some one to say the stuff is infact brake fluid I ain't putting in my planeG

Simatos, accuracy is important here. It's NOT 5056 and it's NOT "brake fluid". It's MIL H 5606 and it's "Hydraulic Fluid". It may have a further definition such as MIL H 5606(G) or such, but the basic number is:
MIL H 5606 and it can be used for all sorts of hydraulic applications including as a brake fluid in our Cessna 170s. It may be purchased via:
http://www.aircraftspruce.com/catalog/l ... l_bflu.php