REFLECTOR: HYDRAULIC PUMP

[dean fitzbag]

Just because you don't see any leaks doesn't mean that there are none.  The dump valve, the cylinders, and the sequence valve can leak internally.  This sounds very hard to fix, but it isn't.  Buy some caps and double male connectors.  Then start bypassing these components.  You may have more than one leaking internally.  After each bypass bring the system up to pressure with the gear up and see if the recycling goes away.  Of course neither or either gear may not move depending on what has been bypassed.
  ----- Original Message ----- 
  From: Tom Martino<mailto:tmartino at troubleshooter.com> 
  To: reflector at tvbf.org<mailto:reflector at tvbf.org> 
  Sent: Sunday, July 16, 2006 3:14 PM
  Subject: REFLECTOR: HYDRAULIC PUMP


   
  BACKGROUND:  This query comes as a result of my hydraulic pump turning on and off quickly when gear was retracted.  A gear retraction test revealed that the system is not holding pressure. 

  QUESTION:  Can anyone tell me the actual Manufacturer, model and part number for our Hydraulic Pumps? (I realize I can get them from Velocity, but I am curious about some other things and would like to contact the manufacturer.)

  Also . I am told there are "rebuild" kits for them.  I know the rebuild kit includes "o" rings . but they are for keeping the fluid from leaking to the outside world.  

  My pump (and plumbing) had absolutely NO LEAKS - anywhere.

  The only conclusion I could make is that the pressure was "bleeding off" from the high side to the low side and the only parts in the pump that maintain internal pressure are the "spring loaded metal-seated cone check-valves" (one on each side).

  Do the rebuild kits include new springs and cones?

  Also . has anyone ever had the "dump valve" leak internally from high to low side?  Without showing any wear or exterior leaking?  A local hydraulic shop tells me they hardly ever see those simple quarter-turn vales go bad.

  Any help on any of this would be great!

  Tom

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