Replacing O-rings in Gear Uplock Cylinder

[ghancock]

When the main gear go up on a Twin Commander it pushes on a very small cylinder that locks the hydraulic pressure into the main gear line, which is what holds it up.  If your main gear are not staying up on their own during annual or you're getting hydraulic fluid in your main gear well and you're not sure where it is coming from, this is a very good place to look.  To rebuild these cylinders you can send them off and for $450 you can have them rebuilt, or... you can go buy $2.00 worth of o-rings and just replace them.  The cylinder comes apart pretty easily and we ended up using a thick piece of baffling material to hold the piston while unscrewing the adjustment screw.  We measured the length of the assembly before taking it apart in order to get it adjusted exactly the same going back in.

Here are a few pictures of the process and a link to the entire gallery of photos and videos while doing the job.

Entire Gallery: https://gshutter.smugmug.com/Airplanes/My-Planes/Commander-680Fp/Gear-Uplock-Cylinder

[Huck-Mag]

Good stuff Glenn! Keep at it.

Brent