<VV> em convertible pump question

[bob mccrum]

john, don't know much about convertible tops, but do know something about
hydraulics.  Is it possible the pump could be cavitating (picking up air
instead of hydraulic fluid?) and not rerunning until cavitation stops?  when
the pump stops-is it still making noise, without action(s) being performed.
the pump noise should change a lot when cavitation occurs, but pump should
still run.  i.e., what exactly is it doing?  if it's cavitaion, could be
blockage in the return area or tank.  bob mc
----- Original Message ----- 
From: "John Headley" <robedinpurple@yahoo.com>
To: <virtualvairs@corvair.org>
Sent: Friday, December 31, 2004 8:39 PM
Subject: <VV> em convertible pump question


> Hello all,
>
> A while back, I wrote about finding a company called
> Hyrdo-e-lectric in FL and purchasing some convertible
> top cylinders and lines to replace the very leaky ones
> in my 64 monza.  The system is back together, and the
> cylinders and lines appear to be a good fit.  However,
> I am having some issues with the operation of my
> hydraulic pump.  The pump is a Clark's repo purchased
> by p.o., and I don't have any idea how long it's been
> in the car or whether he might have abused it (i.e.
> running too low on fluid, etc.)  The pump will stop
> working while cycling the top up or down and just do
> nothing for approximately 30 seconds, then will be
> able to resume, but might stop again.  It can take
> several tries to get the top up or down in this
> manner.  I don't have a lot of history on this system,
> it was leaking so bad that I only cycled it a few
> times before disconnecting the system altogether (but
> it never did this in the few times I used it).  Here's
> what I've done so far to try to track this down:
>
> -Check all lines for kinks, one was getting trapped
> but freeing it and keeping it out of the line of fire
> did not solve the issue.
> -Reverify fluid level up to filler hole height in
> horizontal (mounted) orientation.
> -Run cylinders up and down while not attached to the
> top mechanism.  No change, pump still cuts out some
> times (should mean it's not a binding issue).
> - Hook up a test light at both power connections to
> the pump and watch in both the up and the down
> direction for current during the event.  In both
> directions, the light stayed on, indicating no loss of
> the circuit.
> - Temporarily re-locate the ground to a better
> location (no change), then improve the contact at the
> existing location with a bigger screw (was loose).
> Still no improvement.
> - Reinstalled original cylinders and ran them up and
> down without being attached to the top frame.  The
> cut-outs happen even with the old cylinders.
>
> I'm hoping someone has a trick up their sleeve,
> because at this point, I don't have many ideas left
> except replace the pump, but they are quite expensive
> ($220 from HEL, more from C's).  I want to exhaust all
> options before I go there.  Any ideas?
>
> -John Headley
> 64 monza convert
> Royal Oak, MI (was 55 today, good car fixin' weather)
>
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