Warbird Information Exchange

Does anyone know where one could acquire some original WW2 Hydraulic Fluid for P-40's? The family has noticed our supply diminishing slowly but sheerly and was just wondering if anyone knew where we could get the original stuff and not the new stuff that requires the seals to be changed.

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Cheers,

Glenn Maude

Co-Owner of: http://www.rcafkittyhawk.com
A website dedicated to the P-40 AK803/1034

there is a difference???

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Long Live the N3N-3 "The Last US Military Bi-Plane" 1940-1959
Badmouthing Stearmans on WIX since 2005

It depends on if your aeroplane is running on either vegetable based oil aka car brake fluid or mineral oil that most people would be more familiar with, also known as MIL-H-5606 or red oil. In the Wirraway, originally the vegetable based oil was used. These days, most of them have been converted to run on mineral oil. My Wirraway manual, IIRC, (I'm not at home!) has a procedure for making your own hydraulic oil, if you are stuck, by mixing castor oil and acetone, in what proportions I can not remember. Hope this helps

There is a big difference in the two types of hydraulic oil. I heard once the pilot of the Canadian Warplane Hurricane, Rick Frank? , had a big leak in flight with the earlier style fluid and it really caused a problem with his eyes. The newer type, the red 5606A doesn't seem very toxic in just handling it like pouring, but of course I wouldn't want to get it in my eyes. It does have sort of a obnoxious smell.

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Bill Greenwood
Spitfire N308WK

Mil H 5606 is being replaced in modern military acft with PRF 83282 which is a synthetic oil. The seal manufacturers state that Buna N and similar old style seals are compatible with both 5606 and 83282. The hyd oil that you cannot use in a warbird is the phosphate ester based type like Skydrol, which is used on large commercial acft because it is fire resistent. 5606/83282 style seals will swell to twice their size and fail in a mattter of hours in Skydrol, especially in dynamic applications.
Here is a good link for more info.

http://www.bharatpetroleum.com/skies/po ... raulic.htm

Glen, to try to simplify this for you a bit, is your current supply of fluid red in color, or clear? If it is red, you should be safe using the Mil H 5606 fluid which your supplier of aviation oil should be able to supply you. If it is any other color than red, it is likely the vegetable based oil which is no longer commonly in use.