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MarkC

PC servo vacuum connection

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The vacuum tube has become disconnected from the right wing servo for the PC system on my C model. I have studied it as best I can but cannot see how to get access to the rear to see how to reconnect. Any advice?

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Something to consider...

The tube is made from plasticized PVC. It hardens over time and doesn't want to stay In place.

Good to get new tube before going in...

Best regards,

-a-

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The aileron servos have a single mounting screw on the back. The tubing also connects in the back. From the access hole, you see the front of the servo. Arrggghhhh!!

Take off your radio access panel on the left side, the tail servos are visible for comparison; but the aileron servos are smaller.

I tried but could not reach my aileron servo mounting screws. Fortunately my A&P had smaller hands. This would certainly be a good time to check the tubing and see if it needs to be replaced.

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As I recall, next inspection panel inboard gives some access.  You may, or may not, have to remove servo to accomplish task.  Tight, but not the toughest job on a Mooney.

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Thanks for the input guys. You are confirming a lot of what I am seeing

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Been there, done that.  Suggest you disconnect the aileron rod end where it attaches to the aileron itself (not where it attaches to the bellcrank in the wing).  This allows you to raise the aileron up 90+ degrees, which exposes an access hole in the trailing edge of the wing that's lined up with the nut on the servo.  A socket on an extension fits easily into the hole, allowing you to unbolt the servo and pull it out of the wing.  Theoretically, there should be enough extra tubing to reconnect the tubing to the servo outside the wing, then you can slide the completed assembly back in and re-bolt the servo in place.  You'll probably need to make a fresh cut on the tubing, as odds are good that the connection failed due to the tubing crumbling.

 

With regard to what carusoam said, yes, the tubing can harden over time, and that may be your issue.  But note that even brand new stock isn't especially pliable.  We replaced all our vacuum servo tubing with new stock from Brittain a few months ago, and I couldn't tell much difference between new vs. old.  Well, other than the holes and patches in the old stuff, which was the reason we were replacing it. :D  

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Thanks again everyone. I disconnected the aileron as described and found an access hole. But the access hole on my plane was not aligned directly with the nut on the servo. I did use a right angle wrench and it was just enough to remove the nut turning it about 1/16th of a rev each time I engaged it. So I was able to remove the servo and reattach the tubing and it now appears to be securely attached. Thanks for all the good advice.

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Check the tape and make sure it is not leaking while it is out. It's not any more fun to remove it the second time either.

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Been there, done that a few weeks ago. Your technique to disconnect aileron was the only way to get in mine. Now you will want to check the other wing. Lastly, I replaced all the tubing under the dash with new. A royal PIA, but PC works great now..I had a small tear in the left boot of the servo.

 

-Tom 

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1/4 inch socket set with lots of extensions, joints, sweat, patience, and perseverance........The whole time keep saying to yourself, I'd like the find the a-hole who designed this installation and get him to try and replace the actuator.

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