trim cylinder issue

[DFWcobalt]

Apologies for resurrecting this one but having a similar issue with my VP outdrive; holds trim on the trailer just fine, but under load the prop thrust pushes her right back down.
Local shop said they couldn't find any leaks, but I can assure you that the outdrive will get pushed down. No oil visible on the drive cylinders, or under the drive when on the trailer.
I suspect the check valve in the pump. Any way to diagnose this with certainty? Would a leaky check valve just allow pressure to escape, or would/could there be a tiny leak somewhere on the pump and oil would go into the bildge?
thanks

 

[Scott Danforth]

moved your post out of an old thread

you have a leak at the cylinder. its bypassing the piston.

find a different shop, get your cylinders rebuilt or rebuild them yourself.

 

[DFWcobalt]

Thank you very much!

I'm quite sure the rebuild will be way cheaper than the local cobalt shop asking for 5k to replace the pump and both cylinders!