Hydraulic fluid is definitely not all the same. While in the military, I know it was eons ago, we always had to battle leak issues for aircraft that used Skydrol. Parts people were notorious for giving us O-rings that should work "because they were the same size". After a major hydraulic leak on the engine-driven pump, in flight, many select words were used to demand the correct part.

True, this isn't an aircraft, but who knows what major grief this will cause at the most inopportune time. That's when all of my failures seem to occur.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )