Thanks for your advices! But we have done as all that you said before, and the result is TIBVs not working. I'm trying to find the main reason that make the TIBVs not its close.

Now, I have a document (drawing enclose). Can you look through and examine? After that please tell me the main faults.

Thanks a lot.

Enclose:
servo.jpg

Assembly.jpg

Hydraulic diagram.jpg