1970 M20C PC System Servos

[DanielB]

Good day all!

My new to me Mooney M20C is in for its first annual (under my ownership). I asked the shop to check the PC Servos, as the PC system did not seem to be working. Low and behold, all the servo seals have pretty much disintegrated. So, looking to replace all four servos, or if someone has a usable repair method, that'd be great too.

TIA

Dan B
M20C N9452V 

[Hank]

I sent a NOS rebuild kit out to see if someone can replicate it. Still waiting to hear back. I need to remind him, it's been a couple of months.

Small tears can be repaired with 3m 33 electrical tape. Disintegrated boots will.need to be replaced. Note that you have one in each wi g for the ailerons, and two in the tailbone for the rudder. Thise with a B6 altitude hold unit have two more for the elevator. 

[JoeM]

Dan;

I have bought several sets off Ebay MS and FB. Even the ones stated "not leaking" usually leak. Don't pay too much without a return guarantee. When you get them, you should test with a Harbor Freight brake bleeder to see if the boots will hold 5 psi for a minute or so. As Hank said, you can repair reasonably large tears with 3M electrical tape (not the cheap Chinese stuff) and Permatex. If you still need some that don't leak or are repairable, I have several I can go through to see what's usable. I finally got mine working.

[takair]

I have some for sale in the classified section…

[SSimpson77]

Just a thought but would the little “tire patch seals” work for small pinhole leaks? Thin, pliable, and adhere well to rubber tire tubes. 
Find them at big shopping stores in the bike tires section.

[Igor_U]

On 12/17/2021 at 10:51 AM, DanielB said:

Good day all!

My new to me Mooney M20C is in for its first annual (under my ownership). I asked the shop to check the PC Servos, as the PC system did not seem to be working. Low and behold, all the servo seals have pretty much disintegrated. So, looking to replace all four servos, or if someone has a usable repair method, that'd be great too.

TIA

Dan B
M20C N9452V 

Dan,

I just mentioned rolling diaphragms from Bellowfram in another post. Download their catalog and you should be able to find one that is similar or same as the one on Brittain servos.

Try p/n  3-350-212-DCJ or 3-350-280-DCJ; those can't be that expensive.

 

Disclaimer:

I haven't tried this since my servo's are all good but would like to. I might by another, correct servo for flight controls and try to OH it. Good luck

 

[Don Gates]

I have a full set of servos, an entire PC system in fact, that I just pulled out of my 65 M20C.  TC pulled out of the tail cone.  Make offer.  Working when removed.