Mailing List lml@lancaironline.net Message #47855
From: <vtailjeff@aol.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Question about Hydraulic Pump
Date: Wed, 02 Jul 2008 12:41:56 -0400
To: <lml@lancaironline.net>
what kind of airplane IV/ Legacy/ 360?


-----Original Message-----
From: GT-Phantom <gt_phantom@hotmail.com>
To: lml@lancaironline.net
Sent: Mon, 30 Jun 2008 8:04 pm
Subject: [LML] Question about Hydraulic Pump

Hi all,
 
I'm a buyer not a builder, and I'm trying to diagnose an intermittant gear problem.
 
I've replaced the old-style pressure switches with the new ones, and it still occurs. 
 
Sometimes when I raise the gear handle it works just like it should - the gear motor kicks on and runs quickly and solidly until the last motion stops with a solid "thunk."  Other times the motor runs as if against resistance, stops, then cycles every few seconds until the gear eventually retracts completely.  When this happens, if I put the gear handle down the gear does not extend - until I momentarily move the "dump" valve to the dump position and back, which immediately causes the pump to run until the gear is down and locked.
 
So, I presume there is a double check-valve system in the pump which is supposed to completely release pressure on the non-working side which is "sticking."
 
Questions:
 
- Are the check valves INSIDE the pump assembly (I think they must be)?
- Can they be refurbished, or do I have to buy a new pump?
 
Thanks for your confirmation / tips.
 
Bill
 
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