REFLECTOR: Landing Gear Pump Not Holding Pressure

[John Abraham]

Your pump system uses 1050psi up and 550psi down. Sometimes you will develop external leaks which are easier to trace. You may also get internal leaks which we have seen. You have to isolate one part of the gear system at a time. One thing to be cautious of if that if you have a low battery or leak you do run a high risk of hurting a relay in the gold box. If you hear your pump pulsing or the relays chattering turn off the pump with the breaker or the master switch. 

You may have to use a pump rebuild kit if your pump is what is leaking. Could also be either a bad pressure switch or one not adjusted correctly. 

John

On Jan 6, 2013, at 8:22 PM, "Laurence Coen" <lwcoen at hotmail.com> wrote:

> Your response is 100% wrong.  There are two pressure switches.  One for gear up and one for gear down.  You can prove this for yourself by putting the manual gear down valve in the down position and turning the master on. The pump will run continuously because there is no gear down pressure.
> 
> Larry Coen
> N136LC
> 
> --------------------------------------------------
> From: "Doug Kanczuzewski" <doug at customstudio.com>
> Sent: Sunday, January 06, 2013 5:25 PM
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Subject: Re: REFLECTOR: Landing Gear Pump Not Holding Pressure
> 
>> When gear is down you should not have any pressure and pump would not run. It only runs to maintain pressure when up.
>> 
>> Doug
>> 
>> -----Original Message-----
>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Darrell & Nora Kufalk
>> Sent: Sunday, January 06, 2013 3:21 PM
>> To: 'Velocity Aircraft Owners and Builders list'
>> Subject: Re: REFLECTOR: Landing Gear Pump Not Holding Pressure
>> 
>> I didn't explain that very well.  The switches were still connected.  I capped the 2 lines going through canard bulkhead and I have the mechanical door actuator.  The switches are working correctly.  As soon as the pump stops, the pressure bleeds off somehow.
>> 
>> 
>> 
>> -----Original Message-----
>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Carl Hoffman
>> Sent: Sunday, January 06, 2013 3:53 PM
>> To: Velocity Aircraft Owners and Builders list
>> Subject: Re: REFLECTOR: Landing Gear Pump Not Holding Pressure
>> 
>> Something is not making sense here. If both outlet tubes are capped off, where are the pressure switches that would cause the pump to cycle?
>> One of the outlets is for the up side, and the other is for the down side.
>> Maybe you just have a faulty down side pressure switch somewhere causing it.
>> Over the past 12 1/2 years I've replaced mine twice.
>> 
>> 
>> On 1/6/2013 3:10 PM, Darrell & Nora Kufalk wrote:
>>> I was testing my landing gear on jack stands and gear pump began
>>> cycling every few seconds.  It would only do it in the down position.
>>> I traced it down to the pump itself.  With both outlet tubes caped off
>>> it still cycles once or twice per second.  I pulled the pump out and
>> removed the reservoir.
>>> I took apart what looks like 2 check valves and they look ok to me.
>>> I'm not sure what to do next.
>>> 
>>> Anyone else have a problem like this?
>>> 
>>> Darrell Kufalk
>>> 
>>> 
>>> 
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