Danny

If you have to change the valve I suggest replacing it with a three
way type that will dump to the pump reservoir. This will eliminate a
potential failure mode in the pump. You can get the valve from
Lancair. It is used on the legacy and of much better quality than the
earlier 360 valves

Tom

Sent from my iPad

On Mar 29, 2012, at 9:02 AM, "Danny"  wrote:

*

Nope, I took the NW actuator out of the system and installed a gauge
on that pressure line to check. I also played with the dump valve
today to see if a slight movement of the handle made a difference
… it did. This weekend I’ll cap it and see what kind of pressure
I get but my guess is that’s the problem.

Danny

LNC2-360, 550 hours

N 38° 43' 25.7"

W 77° 30' 38.6"

FROM: Sky2high@aol.com [1] [mailto:Sky2high@aol.com]
SENT: Wednesday, March 28, 2012 9:06 AM
TO: lml@lancaironline.net [2]
SUBJECT: [LML] Re: LNC2 gear diagnosis

Danny,

From what you reported it would seem that the nose gear actuator is
the real problem. How about the door actuators? One possible
analysis is that you don't see the 1200 psi because the leak is
greater at the higher pressure and then slows a bit as the pressure
goes down or the actuator has its worse leak at full retraction and
less when the piston is not at the full retraction position...

Scott Krueger

In a message dated 3/27/2012 10:32:25 P.M. Central Daylight Time,
danny@n107sd.com [3] writes:

If any of you have a suggestion, I’d appreciate your input.

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’m 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’s the
question, do I have a faulty gear dump valve, a leaky pump, or
both?

Danny

LNC2-360, ~550 hours

N 38° 43' 25.7"

W 77° 30' 38.6"

Links:
------
[1] mailto:Sky2high@aol.com
[2] mailto:lml@lancaironline.net
[3] mailto:danny@n107sd.com
[4] mailto:danny@n107sd.com