From: marv@lancair.net
Subject: Re: Question about Hydraulic Pump
To: lml
Date: Wed, 02 Jul 2008 12:40:40 -0400
Message-ID: <web-3001037@logan.com>
In-Reply-To: <018401c8db9e$3525bb00$650fa8c0@LHenneyLaptop>
References: <018401c8db9e$3525bb00$650fa8c0@LHenneyLaptop>
MIME-Version: 1.0
Content-Type: text/plain;charset=iso-8859-1;format="flowed"
Content-Transfer-Encoding: 8bit

Posted for "LHenney" <LHenney@charter.net>:

  Bill,
  
  
  The statement:
  
  
  Other times the motor runs as if against resistance, stops, then cycles
  every few seconds until the gear eventually retracts completely.
  
  
  
  One might infer that that up pressure switch is just set very low.  Another
  issue that could be related is the spool valve orientation.  When properly
  oriented it allows the "backside" pressure to bleed back to the reservoir
  while the motor is running.  Much has been written on this:  However, the
  quick check is while gear are retracting reverse the switch to down.  If
  motor immediately reverses and lowers gear spool valve is correct.  However,
  if a slight delay occurs the spool valve is in backwards (which many from
  Lancair (circa. 1996) were installed backwards.
  
  
  
  The beat all end all to the discussion is to install and read pressure
  gauges.  They cost about $20 ea from Lancair and are invaluable for trouble
  shooting.  I found my down circuit to be set below 100 psi.  It worked but
  was way off the target 500 psi.  Get the switches and document some
  operational function and all can be clarified.
  
  
  
  Larry Henney
  
  L 360 800 hrs
  
  My chirps were solved by honing the tube in which the spool valve, check
  valve bodies sit.  It was gooey up with o rings and debris from 800 hrs of
  operation.  Much time was spent thinking I knew what was happening until the
  pressure gauges resolved all.