My hydraulic pack that retracts the gear has packed up (again). It is a Prestolite HYC5005.
So I guess my options are:
Prestolite apparently sold the division in approx. 2000, and the new owner doesn’t seem to be interested in the products. The company that used to overhaul them for my part 145 apparently cannot do it any longer because they can’t seem to get brush kits.
Oildyne is a Parker Hannifin subsidiary. Everybody seems to use them nowadays, from Glasair to Lanceair to Piper to Boats. Unfortunately, changing to the Oildyne pack would need a mounting bracket which seems to be hard to come by.
Does anyone have any opinion on these packs? Is the reliability of the Oildyne packs better than the Prestolite packs?
A web search turned up two minor problems within the last 30 years or so. Seems to be quite impressive to me.
I recommend a quick read here It talks about the Parker/Oildyne pump.
This story has been played out in various closed (type specific) forums over the years.
In GA everybody goes ends up doing the same stuff, without necessarily realising everybody else has already done it.
AFAIK Prestolite is finished. There is also LHC who make a very high quality and very pricey gear pump (used on the TBM).
I have a TB20 mounting bracket you can have. Socata sell it for €60. Or you can fabricate one.
The Parker pump is OK. It should last say 1000-2000 cycles and then the motor might start packing up.
However, do check the pressure switch. They all come from Eaton and they made a duff batch around 1990-2005; they basically worked loose and started opening at much lower pressure, intermittently. The symptoms of the switch failing and the pump motor’s commutator getting shagged are very similar, unless you monitor the current during retraction. The former falls to zero and the latter shoots way up… usually 
BTW the pump fluid level needs to be right at the top.
