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From: Lorn H Olsen <lorn@dynacomm.us>
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Subject: Re: LNC2 gear diagnosis
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Danny,

I had the same problem. I traced it to my dump valve. When the dump =
valve was closed all of the way, it leaked. If I opened it 1/2" it =
didn't leak at all. I changed it anyway.

I bought a new Parker Dump Valve from:

     Exotic Automation & Supply
     34700 Grand River Avenue
     Farmington Hills, MI 48335
     (248) 477-2122

for $23.55 in 09/2009.

I don't have the part number. The shop was local and I brought in my old =
one for an exact match.

The installation was easy.

Lorn

> From: "Danny" <danny@n107sd.com>
> Date: March 27, 2012 11:32:05 PM EDT
>=20
> If any of you have a suggestion, I=92d appreciate your input.
>=20
> On my last flight home, with no early signs of failure, my gear pump =
was tripping on about every 2 seconds to maintain pressure.  I figured I =
had a leaky actuator and would have to rebuild it to resolve this; no =
big deal.  I found one leaking and figured where there is one, there may =
be more.  So, I=92m rebuilding all of them.  But, before doing so, I put =
a gauge on the high pressure side of the pump to see if I had internal =
leaks there too.  What I found was that my pump will only pressurize to =
about 950 psi (should be ~1200 psi) and then it bleeds down slowly.  I =
tried to adjust the pressure switch but it made very little difference.  =
To verify the bleeding, I isolated all actuators out of the system =
except the nose wheel.  I put the gauge on the high pressure side of the =
NW actuator line, selected gear up to pressurize the system, and then =
quickly crawled under the plane to look at the gauge.  It was bleeding =
down so fast that by the time I got down there to look at it (~2 sec.), =
it had already lost about 200 psi and then bled down the rest of the way =
in about 7 more seconds.  So, and here=92s the question, do I have a =
faulty gear dump valve, a leaky pump, or both?
>=20
> Danny
> LNC2-360, ~550 hours
> N 38=B0 43' 25.7"
> W 77=B0 30' 38.6"

--
Lorn H. 'Feathers' Olsen, MAA, ASMEL, ASES, Comm, Inst
DynaComm, Corp., 248-345-0500, mailto:lorn@dynacomm.us
LNC2, FB90/92, O-320-D1F, 1,800 hrs, N31161, Y47, SE Michigan