Return-Path: Received: from imo-d05.mx.aol.com ([205.188.157.37]) by ns1.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-70783U4500L450S0V35) with ESMTP id com for ; Thu, 1 Mar 2001 06:13:45 -0500 Received: from ByronMFox@aol.com by imo-d05.mx.aol.com (mail_out_v29.5.) id k.96.10b63e17 (24903) for ; Thu, 1 Mar 2001 06:22:31 -0500 (EST) From: ByronMFox@aol.com Message-ID: <96.10b63e17.27cf8af7@aol.com> Date: Thu, 1 Mar 2001 06:22:31 EST Subject: LNC2 Landing Gear Hydraulic Puzzle To: lancair.list@olsusa.com X-Mailing-List: lancair.list@olsusa.com Reply-To: lancair.list@olsusa.com Mime-Version: 1.0 Just a year ago, I had my hydraulic pump overhauled, replaced the high and
low pressure switches and replaced the O-rings in the left and right gear
actuators. Until about ten days ago it has functioned flawlessly, recharging
on the down side after sitting for several days with a one-second chirp of
the hydraulic pump when the master switch is turned on.

Now, pressure will not hold on the down side. At first occasional and then
persistent chirping of the hydraulic pump every +/- 15 seconds is the case.
Pressure holds just fine on the up side. There are no apparent external
leaks in the system and the level of fluid in the hydraulic pump reservoir is
unchanged.

At first, I thought fluid might be bypassing the piston O-ring in the nose
gear actuator. For reasons too tedious to explain, I was unable to remove it
for servicing last year when I replaced the O-rings in the others. I'm at
loss to understand why fluid would bypass an O-ring in the down position but
not in the up position, particularly when the up side pressure is so much
higher.

Any thoughts?

Thanks,

Byron Fox
LNC2
N3144C
Mill Valley, CA