REFLECTOR: Low Hydraulic Pressure or Pump Check Valve Leaking?

Dugas Bellsouth dugasd at bellsouth.net
Wed Aug 10 08:44:00 CDT 2011


My plastic reservoir has cracked before also but it was obvious on the floor. 

Rene' Dugas
Sent from my iPhone4

On Aug 9, 2011, at 11:37 PM, "Bob Jackson" <bobj at computer.org> wrote:

> I’m stuck in Vernal UT after flying from Orlando, heading for Oregon.  After take-off from Vernal on the third and last leg to Portland, I got an unsafe gear up light.  After returning and investigating (no problem getting the gear back down), I noticed the hydraulic reservoir was down more than a third of the way from the top (we normally keep our fluid level (with the gear down) about ½” from the top of the reservoir.  I refilled the reservoir and tried again.  This time I noticed the pump (light) was cycling even on the ground, and got the same ‘Unsafe UP’ light indication after take-off.
>  
> Does anyone have an ideas or suggestions?  I assume that the pump can’t create enough UP pressure because the up-side pressure relief valve won’t let it.
>  
> Attached is a PDF copy of the Mercruiser Outdrive Maintenance manual – pg 20 has a good diagram of the internal design of (our) gear pump, including shuttle valve, pressure relief valves, etc.  Can anyone explain:
> why the pump’s tank level is different for the Gear UP and Gear DOWN directions (isn’t there the same amount of fluid on both sides of the pistons?)
> if you’ve ever seen a situation where the both the UP and the DOWN sides get pressurized so that neither pressure switch will any longer allow you to change the gear’s position (different problem from mine in Vernal, but just asking since I heard of it once)?
> What could cause my hydraulic reservoir to go down by 1/3 during just the first two legs from Orlando, when it’s never gone down rapidly like that before.  We don’t seem to have any big leaks in the overall hydraulic plumbing that I’ve been able to find yet.
> Is there any way for the hydraulic pump or reservoir to ‘vent’ fluid, other than from bad hydraulic connections that are external to it?
>  
> Thanks for the help,
> Bob Jackson
> N2XF
> <GearPump_HydraulicSchematic_p20.pdf>
> _______________________________________________
> To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
> 
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20110810/70e8e2df/attachment.htm>


More information about the Reflector mailing list