REFLECTOR: HYDRAULIC PUMP

[Tom Martino]

Thanks Greg!
 
Yes it is an Oildyne Pump (now owned by Parker).  It is currently used
for raising and lowering Mercury Outboard motors on boats.
 
Tom
 
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of gpoole
Sent: Sunday, July 16, 2006 5:16 PM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: HYDRAULIC PUMP
 
Tom,
 
The hydraulic pump manufacturer is Parker Hannifin. If I remember
correctly the unit we use was originally designed for use in hydraulic
actuated hospital beds.
 
Greg in Sydney
 
http://www.parker.com/Products/  ....but don't ask me where to find it
in their catalogue...just spent 20 mins looking to no avail....
 
 
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Tom Martino
Sent: Monday, 17 July 2006 6:47 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: HYDRAULIC PUMP
 
Yes, as you will see in my original post, I do understand that
"internal" leaks can exist without external signs.  I have tested the
entire system.  All that remains is the pump or the dump valve.  Do you
know the pump manufacturer?
 
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of dean fitzbag
Sent: Sunday, July 16, 2006 2:36 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: HYDRAULIC PUMP
 
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 
	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turning on and off quickly when gear was retracted.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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