I want to say thanks for all the excellent advice I've received.  Brent Regan, Dan Schaefer and Bill Harrelson correctly identified the root of my problem being an internal leak.  I found the culprit in the dump valve.  Now I just need to replace or rebuild the valve.  Here's how I discovered it:

Last night I capped the low pressure (gear down) line from the three-way Tee that is located just aft of the wing spar.  I first capped the line going to the right gear down (which isolated the right main gear door actuator and gear actuator at the same time).  That didn't solve the problem, so I then also capped the left side also.  When I finally capped the front side to the nose gear actuator and door also (all fittings on the Tee now capped), the problem alleviated.  Then I uncapped the front line, but in the wheel well I capped each line (eventually) to the gear actuator, and then the gear door too.  The problem persisted- so the leak had to be in the dump valve.  I re-attached all the lines, and then isolated the dump valve from the system, and the problem disapeared.

By focusing on the low pressure side, I was able to troubleshoot without having the airplane on jacks.  Also, by capping the lines at the Tee, I was able to isolate two actuators with only one cap, reducing troubleshooting time.

Thanks again to Marv Kaye for the LML service, and for all the advice I got.

James M. Gigliotti

LNC2, Lancair 320 N91LS, 210 hrs TT
Lower Alabama

Bill Harrelson wrote:

  Hello James,
 
  My guess is that you have a somewhat larger problem than bleeding the system.
 
  Here's how to find the leak. I get a supply of plugs and caps (available from Spruce). Disconnect the lines from one cylinder and cap them. Then test the system. If you still have the "burps" disconnect another cylinder and cap the lines. Keep taking one cylinder at a time out of the system until the burps stop.

 
  If you get all of the cylinders out of the system and the burping still occurs, the problem is in the freefall valve or possibly the pump itself. My guess, however, would be that you'll find the problem in a cylinder.

 
  Good luck and let us know what you find.
 
  Bill Harrelson
  N5ZQ 320
  N6ZQ  IV
 

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> It seems I'm having difficulty bleeding air from my hydraulic system. 
>
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