X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 30 Jun 2013 12:12:11 -0400 Message-ID: X-Original-Return-Path: Received: from oproxy13-pub.unifiedlayer.com ([69.89.16.30] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with SMTP id 6354097 for lml@lancaironline.net; Fri, 28 Jun 2013 16:35:52 -0400 Received-SPF: neutral receiver=logan.com; client-ip=69.89.16.30; envelope-from=danny@n107sd.com Received: (qmail 28562 invoked by uid 0); 28 Jun 2013 20:35:15 -0000 Received: from unknown (HELO host295.hostmonster.com) (66.147.240.95) by oproxy13.unifiedlayer.com with SMTP; 28 Jun 2013 20:35:15 -0000 Received: from [98.233.210.64] (port=60819 helo=DannysW7PC) by host295.hostmonster.com with esmtpa (Exim 4.80) (envelope-from ) id 1UsfNy-0006Ue-Pf for lml@lancaironline.net; Fri, 28 Jun 2013 14:35:15 -0600 From: "Danny" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Re: Fwd: Hydraulic pump cycling / Replacing dump valve X-Original-Date: Fri, 28 Jun 2013 16:35:08 -0400 X-Original-Message-ID: <089201ce743e$fb2ba920$f182fb60$@n107sd.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0893_01CE741D.74210E00" X-Mailer: Microsoft Outlook 14.0 thread-index: AQK1ezBaa+Rr3EzqdLtQM33iRERe8pd9h2Mg Content-Language: en-us X-Identified-User: {3234:host295.hostmonster.com:wunderwe:n107sd.com} {sentby:smtp auth 98.233.210.64 authed with danny@n107sd.com} This is a multipart message in MIME format. ------=_NextPart_000_0893_01CE741D.74210E00 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable There is always more than one way to skin the cat. =20 Danny LNC2-360 Mk-II Nothing is foolproof to the sufficiently talented fool. =20 From: Sky2high@aol.com [mailto:Sky2high@aol.com]=20 Sent: Friday, June 28, 2013 3:00 PM To: lml@lancaironline.net Subject: [LML] Re: Fwd: Hydraulic pump cycling / Replacing dump valve =20 Erik and Danny, =20 There are other ways to more quickly isolate the problem. If you = suspect an actuator, first determine if the potential internal leak is = on the up or down side - that cuts the max number of tests in half. = Consider that each gear has a door. So, a better place to cap off a pair = is at the X (actually shaped like a plus sign). This means a max of 2 = tests would isolate the problem to a specific gear/door pair. Then one = more test at one of the actuators should isolate it to a specific = actuator. =20 Yeah, it is a fun time...... =20 Grayhawk =20 In a message dated 6/28/2013 1:34:34 P.M. Central Daylight Time, = danny@n107sd.com writes: You=E2=80=99re about to embark on some real time consuming fun. If you = have one of the old dump valves, they were rated at only about 600 psi = as I recall. The ball valve had a Teflon coating that would deform = under high pressure and leak. You need a Parker valve rated at 2000 psi = or higher. I believe mine is rated at 5000 psi. But, if your dump = valve is that hard to get to, maybe you want to check all your gear and = door cylinders first. There are six of them so get a handful of AN = fitting caps & plugs, jack up your plane and have at it. I=E2=80=99d = also suggest installing 2 hydraulic 3000 psi pressure gauges, one on the = low pressure side, another on the high side. Cap & plug all of the = cylinders, isolate the valve from the pump and then run the pump. If it = cycles, the pump has an internal leak. If not, introduce the valve back = into the system and run it again. If it cycles, your valve is bad. = Then introduce one cylinder at a time, run the pump and see when it = cycles. This all takes a lot of time but it=E2=80=99s the only way to = figure it out. Happy hunting. =20 Danny LNC2-360 Mk-II Nothing is foolproof to the sufficiently talented fool. =20 From: Erik Larson [mailto:asw20747@aol.com]=20 Sent: Friday, June 28, 2013 9:32 AM To: lml@lancaironline.net Subject: [LML] Fwd: Hydraulic pump cycling / Replacing dump valve =20 =20 I have a Legacy, 6 1/2 years, appx 650 hours, we started experiencing = momentary hydraulic pump cycling, averaging now every 6-8 minutes for a = micro second. =20 There are NO external leaks and NO loss of fluid in the system, so I = guess it's time to start trouble shooting to find the internal bypass. = Following some previous postings on the issue, it seems that if it's not = the cylinders, then the next logical place would be the dump valve. =20 At first glance it looks like getting the dump valve changed out could = be quite a job. Anyone that's done it recently care to share some = Helpful Hints? =20 It looks like the only way to get to it, is by disassembling the = throttle quadrant, even then it looks tight? =20 Any advise on that or general trouble shooting advise for the hydraulic = system would be GREATLY appreciated! =20 Erik Larson Legacy/N74FX ------=_NextPart_000_0893_01CE741D.74210E00 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

There is always more than one way to skin the = cat.

 

Danny

LNC2-360 = Mk-II

Nothing is foolproof to the sufficiently = talented fool.

 

From:= = Sky2high@aol.com [mailto:Sky2high@aol.com]
Sent: Friday, June = 28, 2013 3:00 PM
To: lml@lancaironline.net
Subject: = [LML] Re: Fwd: Hydraulic pump cycling / Replacing dump = valve

 

E= rik and Danny,

&= nbsp;

T= here are other ways to more quickly isolate the problem.  = If you suspect an actuator, first determine if the potential internal = leak is on the up or down side - that cuts the max number of tests = in half.  Consider that each gear has a door. So, a better place to = cap off a pair is at the X (actually shaped like a plus sign).  = This means a max of 2 tests would isolate the problem to a specific = gear/door pair.  Then one more test at one of the = actuators should isolate it to a specific = actuator.

&= nbsp;

Y= eah, it is a fun time......

&= nbsp;

G= rayhawk

&= nbsp;

I= n a message dated 6/28/2013 1:34:34 P.M. Central Daylight Time, danny@n107sd.com = writes:

You=E2=80=99re about to embark on some real time = consuming fun.  If you have one of the old dump valves, they were = rated at only about 600 psi as I recall.  The ball valve had a = Teflon coating that would deform under high pressure and leak.  You = need a Parker valve rated at 2000 psi or higher.  I believe mine is = rated at 5000 psi.  But, if your dump valve is that hard to get to, = maybe you want to check all your gear and door cylinders first.  = There are six of them so get a handful of AN fitting caps & plugs, = jack up your plane and have at it.  I=E2=80=99d also suggest = installing 2 hydraulic 3000 psi pressure gauges, one on the low pressure = side, another on the high side.  Cap & plug all of the = cylinders, isolate the valve from the pump and then run the pump.  = If it cycles, the pump has an internal leak.  If not, introduce the = valve back into the system and run it again.  If it cycles, your = valve is bad.  Then introduce one cylinder at a time, run the pump = and see when it cycles.  This all takes a lot of time but = it=E2=80=99s the only way to figure it out.  Happy = hunting.

 

Danny

LNC2-360 Mk-II

Nothing is foolproof to the sufficiently = talented fool.

 

= From:= Erik Larson [mailto:asw20747@aol.com] =
Sent: Friday, June 28, 2013 9:32 AM
To: lml@lancaironline.net
Sub= ject: [LML] Fwd: Hydraulic pump cycling / Replacing dump = valve

 

<= o:p> 

I= have a Legacy, 6 1/2 years, appx 650 hours, we started experiencing = momentary hydraulic pump cycling, averaging now every 6-8 minutes for a = micro second.

 <= /span>

There = are NO external leaks and NO loss of fluid in the system, so I guess = it's time to start trouble shooting to find the internal bypass. =  Following some previous postings on the issue, it seems that if = it's not the cylinders, then the next logical place would be the dump = valve.

 <= /span>

At = first glance it looks like getting the dump valve changed out could be = quite a job.  Anyone that's done it recently care to share some = Helpful Hints?

 <= /span>

It = looks like the only way to get to it, is by disassembling the throttle = quadrant, even then it looks tight?

 <= /span>

Any = advise on that or general trouble shooting advise for the hydraulic = system would be = GREATLY appreciated!

 <= /span>

Erik = Larson

Legacy/N74FX

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