Gear Retraction Issue

[Scudrunner]

Good day, new to the forum. Ive owned my 1974 337G for 3 years now. During our first annual our AME (A&P) discovered some incorrect wiring on our landing gear. He fixed it and I should note we have the gear door removal stc.

Long story short typically when I do my walk around I pump the gear extension handle down with the master off to check for critters making a home etc then when I go flying the gear retracts normally without issue.

When I don’t pump the gear handle prior to a flight which is usually when I fly somewhere then depart a number of hours later or the next day.

When selecting the gear up, the gear will not retract. I select the gear switch back down and pump the handle a few times feel the pressure build and stow it and select gear up and it retracts normally.

My Mechanic has worked on a few 337 over the year but they’re not common. He is definitely the type that knows his way around the aircraft and I and everyone trust his work.

I need to get this solved and I’m planning to bring it into the shop and attempt to figure this out. But before I drag it in as the weather changes has anyone encountered this issue or could provide some guidance.

Thanks

[pilotpat]

We had a similar issue (ours does not have the gear door mod). It turned out to be the pressure switch (basically a plunger pushed by the hydraulic fluid to actuate a microswitch). The fluid sealing o-ring had swelled enough over time to cause the plunger to stick, so when the system pressure fell the pump would not run, and the gear only partially moved. It was an intermittent failure that took quite some time to reveal itself. Good luck!

[Scudrunner]

Thanks. Will start looking into that.