BigD

Thoughts on this picture of PC cylinder piston servo

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This is a picture of my RH aileron PC cylinder piston servo. Rubber boot is torn. Besides this, I can’t see any other reason why my PC is inoperable. If I’m successful in troubleshooting this and narrowing down to this unit, how easy is it to replace? Thanks! 

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1 hour ago, MyNameIsNobody said:

Try taping it and seeing how it works.

That ship has sailed.

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I'll have to rummage deep, there's a particular size oring used as a rubber band to hold the new sleeve on the cannister. Then fold the new sleeve back over the oring and wrap with 3M electrical tape.

This is what Brittain told me when I had to replace one of my aileron servo sleeves several years ago.

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4 minutes ago, Shadrach said:

Some dumb ass said EBay is your friend earlier...

 

Nevermind.

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2 hours ago, MyNameIsNobody said:

Some dumb ass said EBay is your friend earlier...

 

Nevermind.

Ebay is your friend, but can be tricky searching for very specific parts that haven’t been manufactured in 40 years. I’ve seen them called bags, bellows, actuators, servos, pots and likely a host of other things I don’t remember. This auction popped up in my “because you searched” notifications a few days ago, so it was top of mind.  I was certainly not trying to upstage your sound advice! ;)

Edited by Shadrach
  • Haha 1

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Regarding how difficult to replace, it depends on whether your airplane has the access hole in the trailing edge plate where the aileron attaches.  If it does, replacement isn't bad at all.  Disconnect the aileron control linkage, swing the aileron fully up and out of the way, and use a socket wrench with about an 8" extension to access the nut that holds the servo in place.

If your airplane doesn't have that access hole, you have to reach around through the wing access panel to get a wrench on the nut, and that's much more irritating.  You can tell if the access hole is there without disconnecting the linkage - just gently lift the aileron to maximum up deflection and peer in behind it with a flashlight.

For more info, see this similar thread:

 

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Servos come up regularly on eBay.  Nice to have shoppers find the link and spoon feed you the part.  They were cheap in years past.  So cheap that not buying spares was not possible.

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14 hours ago, Shadrach said:

Ebay is your friend, but can be tricky searching for very specific parts that haven’t been manufactured in 40 years. I’ve seen them called bags, bellows, actuators, servos, pots and likely a host of other things I don’t remember. This auction popped up in my “because you searched” notifications a few days ago, so it was top of mind.  I was certainly not trying to upstage your sound advice! ;)

Was not trying to imply an upstage Ross.  Sweet use of the exclamation point though.  Easy does it pard...

Tricky...Not so much in my experience.

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I’d like to thank everyone for their help on this! I’m constantly amazed at the resources and knowledge available here on mooneyspace!  I do have another question on the positive control system. I’ve read the service manual on the subject but have been unable to determine whether or not the “push button valve 2960” is actually wired or attached to anything. Mine is actually completely loose and can be pulled out. The diagram seems to show two wires. Again, thank you for your help! 

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It has a couple of orings but no wires. Pressing it opens the vacuum line, releasing the vacuum to all of the servos.

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@BigD, you can pull the button out of the yoke by hand. May need a key to pry with a little to get it started. Check / replace the orings if you do.

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Yes the button pops right out. Looks like two o-rings are in good shape!

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