Jon … my reservoir also had the exact same crack. Lancair was good enough to sell me one for $65. Takes about 2 months, or did.

It might be the only way to fix it is with heat.

Jim

Thanks, I forgot to mention, my ac has Outback Gear. Re- the inner gear doors vibrate with engine run, taxi, and probably in flight.  

Also:  New Item:
        The hydraulic reservoir at max fill always manages to puke out a bit of hydraulic fluid out the cap to the floor below.  Also, the right side of the reservoir has a vertical split about 2" long.   The split is tight and does not leak when on the ground.    After a flight, a small amount of hydraulic fluid does leak out split as well as from the yellow cap (with its 4 small relief spots to prevent cavitation). 

         I drilled a 1/16th hole in the yellow vented cap for additional ventilation, but no change.

         I used clear silicon for a neat repair of vertical but tight split and it worked for one flight, but then was attacked by the hydraulic fluid and failed and a slight weep appeared again.    Has anyone used a plastic epoxy sealant to repair in place?

          In the end, I believe the reservoir neck needs to be higher and with more ventilation to prevent air pressure challenges.

Jack Addison
N360JS