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Bob Jude asks about hydraulic pump intermittent activation...

Before you buy a new pump, I'd sequentially isolate each cylinder (and the cross
over valve) and see if that affects your problem.  Disconnect the lines at the
cylinder, cap them off and then see if the time to activate changes.  You can do
this now without gages.  It's not bad pressure switches if the activation is
reasonably periodic (constant time intervals).  I don't know what's inside the
pump but there have to be check valves on each circuit and I imagine one of
those could be the problem.  But I suspect you'll find it's one of the
cyclinders leaking internally or the cross over valve.  

While we're on this, my system makes a loud bang noise when the switch is moved
to the down position.  I imagine this is due to the high pressure relief valve
at the pump openning to depressurize the up circuit.  Is a bang (at this
particular point) normal or is it a sign of something wrong?

Regards,
Ed de Chazal


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