Hi Hartmut,
I believe (but could be wrong) that silicone in stable fluid form is
just about chemically inert, lacking the aeromatics and oxidizers in
hydraulic oil.
Let's put the question "in perspective". The odds of failure of a
rubber cup in an oleo would be 100% if someone fills that oleo with
hydraulic fluid. I have not the slightest doubt that this has
happened...many times over the years. I am aware of NO accidents
resulting from such failure(s).
This leads me to believe that disassembly and cleaning of oleos (I like
the degreasing and low viscosity flushing effects of acetone) and
subsequent filling with DOT 5 fluid does not raise, even remotely, a
genuine "safety of flight" issue if 100% "failure" occurs. Were the
cup to totally dissolve, the first subsequent landing would eject most
of the fluid in that oleo through the clearance between the piston and
cylinder (as that would be the "path of least resistance"). Were the
landing a "good" one, the failure might go unnoticed except that the
resulting mess would be impossible to ignore.
If no problem or deterioration is evident in the period from
installation to the next annual, I would presume "acceptable"
compatibility indefinitely.
Regards,
WRB
--
On May 24, 2010, at 14:58, Hartmut Beil wrote:
William.
The question is not so much legality, but rather if the rubber is
compatible with the Dot 5 fluid.
I am all for DOT 5 , since it keeps the water out. But what about the
rubber cup compatibility?
Hartmut
