Hitting the dump valve may or may not help the problem.
It depends on how much of a temperature increase you incurred.

Wolfgang

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Wolfgang,
I suggest a review of the Legacy hydraulic system schematic in the following document (Legacy Addendum).
http://www.n91cz.net/Hydraulics/Lancair%20Hydraulics.pdf
You will see that the Legacy has a three-way dump valve that connects both high and low sides to the reservoir.  It will always dump pressure regardless of temperature rise.

Extension failures were more common in the 320/360 and can be resolved by simply adjusting the low side pressure switch higher (and if needed, the relief valve also) -see page 10.  The higher volume gear pump in the Legacies reduces the exposure to the failure when using stock pressure settings.
The initial extension sends a pressure pulse through the system and can, if condition are just right, shut the pump down.  The hydraulic system will think the gear is down and pressurized.  This type of failure is what caught Lorn off-guard and resulted in a gear-up landing. See attached, the photo of Lorn’s pressure gauges after he slid to a stop.  Both gauges are 500 psi +/-.
The gear selector is down, the low side pressure switch is open and the high side pressure switch is closed.  The very same condition as when the gear is fully down and locked.  Based on prior descriptions of your module, it will not detect this condition as a failure and will do nothing to fix it.

Most Legacy pumps have spool return springs which can cause pressure rise in both sides due to a temperature increase.  This is more often an issue sitting on the ground on a hot parking ramp where the potential temperature swing is much greater.  I recommend removing these springs per instructions in this link:

Chris Zavatson

N91CZ

360std

www.N91CZ.net