Old Grease on Trim Chain

[Derek]

Last 2 annuals were at a MSC. Getting one done by a different shop this time around.

My IA sent me the attached picture of the chain.

Sort of surprised me that the chain was in this state. Is the chain something that is normally cleaned up and greased at annual? I even had a new trim chain cover installed 2019 annual (because it was missing)... 

How long would it take to accumulate that amount of funk on the chain? And what's the risk associated? Chain corrodes and breaks due to gunk in the grease? Gunk causes it to jam?

New owner... Trying to learn things...

Thanks!

[Utah20Gflyer]

I have no input as to what is normal as I am a new owner but my plane just went in for annual and I will definitely have them check this area on my plane for cleanliness and lubrication.  What ever is normal that chain could be better.   

[Ragsf15e]

That is a common problem. A better mechanic will chime in, but there are reasonable ways to clean it. Many of them go until it gets hard to turn the trim wheel before people realize all the gunk. But yes, an MSC probably should notice that.

[A64Pilot]

It’s not really under much stress and sees actually very little use, think how much use a bicycle chain gets in comparison.

To clean mineral spirits and a few rags, a toothbrush to do the actual cleaning.

My guess would be once every few years is plenty, every year won’t hurt but is probably excessive. Most I feel probably never get cleaned and relubed.

Probably wait until the belly is off to clean it.

A light coating of pretty much any grease would be fine, but I’m sure the MM calls out a specific one and you can’t go wrong following it.

Edited November 3, 2021 by A64Pilot

[Bartman]

It is far more likely to have a problem with the chain without the cover for a single flight due to a foreign body getting stuck in the mechanism than it is that gunk will cause you a problem in the next 10 years. All kidding aside, good on you for installing the cover for the chain and gear. In fact, my aircraft did not have one when I purchased it and my IA felt it was a safety if flight issue. It was one of the very first things we fixed. 

[PT20J]

This is one of the few instances where I don't follow the manual. Who puts grease on a chain? It collects dirt and the grease cannot get down into the rollers to lubricate them. There are lots of chain lubes available, but since the trim chains (there are two if you have a trim servo) are so lightly used, I just use 3-in-one or LPS 2. Don't forget to lube the trim wheel shaft. Mooney should really have used an oilite bushing, but it's hardened brass and wears out of round if not kept well lubed.

Skip

[N201MKTurbo]

I think that chain has a master link, you can take it off and clean it in the parts washer or a coffee can.

Mine looked just like that. After I cleaned it I lubed it with a paraffin based bicycle chain lube. It looks way better and feels better too.

I’m with @PT20J, grease is nuts. I will say that mine looked like brand new when I was done cleaning it, so the grease gunk preserved it pretty well.

[Derek]

Thanks all

[carusoam]

Derek,

That’s just one end…

Find the other end… expect to do some grease cleaning…. The trim screw is known to have its grease turn into rocks at either end…

There is something funky about the grease that got used for decades….

While you are in there…. Make sure full up and full down trim actually goes the whole distance…. 
 

It should operate easily and smoothly….

See if you have a friction brake up by the trim wheel…

PP thoughts only, not a mechanic…

Best regards,

-a-

[Yetti]

That's not original grease.   Mine had original grease on it and it had dried to a brownish clear gunk.    So mine had never been cleaned.    Tooth brush to clean.  That is at least 10 years of dirt off a grass strip.   No I don't think it is called out on the Annual Inspection.

[47U]

Were there conflicting statements in the mx manual for lubrication of the trim system over the years?  My C also had grease on the trim chain.  Whacky.  Manual 106 says TriFlow on the trim chain and gears, grease (with graphite) on the trim screw and stops.