Saratoga Gear Retract Problem

During day one of my 2000 Saratoga's annual today my mechanic and I observed
the following problem. If anyone has some experience with this or they have
a mechanic that has experience with this I would love to hear about it:

Here is a description of what we are observing:

1) Gear retraction is initiated with handle being placed into the gear
up position

2) Nose gear and main gear unlock and start retraction

3) Gear Unsafe light illuminates simultaneously with gear unlocks

4) In about 1-2 seconds, nose gear completes retraction first (this is
normal as far as what I have observed in the past both on my plane on jacks
and on observing others from the ground departing from airports)

5) Main gear comes up part way but hesitates until nose gear completes
retraction - again I believe this is normal

6) Main gear almost completes retraction in about 2 seconds after nose
gear - a few inches from being completely retracted - this is where
something has changed.

7) Pump Motor shuts off for approximately ¼ second

8) Pump Motor starts again for approximately ¼ second and gear moves
up a little more (maybe ½ inch to 1 inch)

9) Pump Motor shuts off again and restarts again 3-5 times in the same
pattern of quick off and ons before gear is completely retracted and pump
motor remains off

10) Gear warning light extinguishes about the time or slightly before the
pump motor shuts off for the last time


This process is very repeatable. Only the number of quick off-on cycles of
the pump varies slightly. The pump almost always remains off for many
minutes once the gear is completely retracted. The gear was left in the up
position for at least 5+ minutes at one point and we did not observe any
restart of the pump. We did observe a quick on-off cycle of the pump
perhaps 5 seconds after retraction during just one of 15-20 retraction tests
performed, but again, normally the pump would shut off after the last cycle
and remain off for many minutes during our testing.


Everything seems normal compared to what I have observed when we did the
annuals before except for the pump cycling off and on near the end of the
main gear retraction cycle. We have studied the hydraulic and electrical
schematics for the system and looks like there is a pressure limit switch
that is responsible for stopping the pump motor when the pressure reaches
approximately 1800 psi. This should occur after all the gear is retracted
and against the physical stops. We are theorizing that this switch or the
contactor that it operates could be faulty and prematurely stopping the pump
prior to the gear being completely retracted. If the switch opened at a
lower pressure for instance or cycled between opened and closed in a lower
pressure range then it was supposed to we are thinking that the symptoms we
are seeing would result. According to the maintenance manual the switch is
supposed to close at 200 to 400 psi and open at 1800 +/- 100 psi. We have
looked all over for anything impeding the main gear retraction and were not
able to identify any hang-ups there. We have also verified that adequate
5606 is available in the reservoir of the pump.


Again if anyone has some insights on my gear retract symptoms I would sure
like to hear about it. If you believe our theory about the pressure limit
switch being bad is unlikely and that it would be wiser to go down another
path I would also like to hear about that too. My mechanic and I will be
all over this tomorrow so if you know anything about this post what you
know.

- George