Grease on prop

[bradp]

Hi all

I'm looking for some help/advice.  Flew from Pittsburgh to NJ today.  The plane is about 10 hrs out of annual and I noted what I initially thought was bugs but on inspection it looked more like grease.   No sign of oil anywhere.  I cleaned it off ran it up, cycled the prop, and took it around the pattern.  Noted a definite pattern of grease on the prop blades.  I took some photos but because of the sun needed to doctor them significantly to make the pattern show.  

Tomorrow I'm going to pull the spinner and cowl and thoroughly inspect.   The crank case seal was replaced about 25 hrs ago.  I don't have the prop log with me so I don't know if grease was injected or not as part of the annual.   The plane has (finally) otherwise been performing flawlessly.  

Ill need to make a determination tomorrow whether this is an airworthiness issue or not. I'm thinking if I'm  thoroughly convinced it's from injection of grease, I'll fly her home.  If I'm not convinced I'll drive the family home and get the plane to Senisech.  

Thanks for your advice and take care

 

b

[Guest]

Your McCauley propeller has no greasing provisions.

Clarence

[bradp]

Ok thank you Clarence. It's only the Hartzels that have greasing provisions then?. Should I be looking for a bad seal then - blade or crank case?

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[Marauder]

I would clean the propeller off and check behind the spinner. I have seen some marks like those after I cleaned the plane and some of the water in the spinner loosened up crud.

Also, there is a guy on this site who works for a prop shop. I would send him a PM with the pictures and see what he says. His name is Cody Stallings. Let us know what you find out.

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[Marauder]

Ok thank you Clarence. It's only the Hartzels that have greasing provisions then?. Should I be looking for a bad seal then - blade or crank case?

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Where in Jersey are you? We have several members who might be able to point you to a shop.

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[bradp]

Right now at 39N Princeton Airpark.

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[carusoam]

You are at my home drome.  Let me know if you need anything. The maintenance shop is open early on Saturday.  The lead mechanic is named Jeff in the event you want to talk to somebody...

check your pm...

best regards,

-a-

Edited September 12, 2015 by carusoam

[markejackson02]

I had the same thing about a month ago, there would be grease, not oil on the cowling after each flight.  Prop needed new seals around the blades so had it overhauled.

 

Edited September 12, 2015 by markejackson02

[Shadrach]

I'm curious about the failure mode. My experience with Hartzells is that the seals herniate the first time the prop is cycled after they are "over serviced" with grease. This McCauley has no provisions for servicing, so what would cause both blade seals to herniate at the same time? Or is it that one seal failing makes such a mess inside the spinner that it looks like both have failed?

[Guest]

I would clean the propeller off and check behind the spinner. I have seen some marks like those after I cleaned the plane and some of the water in the spinner loosened up crud.

 

Also, there is a guy on this site who works for a prop shop. I would send him a PM with the pictures and see what he says. His name is Cody Stallings. Let us know what you find out.

 

 

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I agree, looking at the pictures it's hard to see if the staining is coming from the blade root/ hub area or not.  Remove the spinner, clean everything thoroughly, reinstall the spinner, do a ground run, if dry go fly it.  

A leaking crankshaft seal usually deposits oil into the starter flywheel/ ring gear.

Clarence

[N201MKTurbo]

The way I understand it, if the dome wears out, or the piston seal wears out, oil will make its way past the piston and fill the hub with oil. This oil will eventually force the grease in the blade bearings to be pushed out. Eventually it will change from grease to oil. 

The prop is telling you it needs help. It will not fail catastrophically, you can fly it home like that, but it needs to go to the shop soon.

[Cody Stallings]

That is a very common problem with a 200 Series McCauley. The blade Orings get hard, an it poops a little greese down the blade.

A Reseal will fix that issue.

[Shadrach]

That is a very common problem with a 200 Series McCauley. The blade Orings get hard, an it poops a little greese down the blade.

A Reseal will fix that issue.

so it'sa matter of poor seal quality? It's not really a high heat environment. Any theory as to why they harden?

[Cody Stallings]

The seals are very good at what they do, but they will get hard overtime( like any other Orings). The blade Orings are somewhat exposed to the elements being the snapring does not keep moisture, grit out.

Some props hold greese for 20yrs, some will leak in 10yrs. Your prop is a 6yr 2000hr prop.

If a Hub has had corrosion worked out of the blade sockets, the Oring will sometimes have a hard time sealing properly due to the increased size of the blade socket. 

On certain models propellers we are allowed to cut the blade socket an install a strip of .010 Teflon in the hub: Good by greese/oil leaks. The Blade Orings have a much longer life mated to Teflon, as opposed to riding on Shotpeened Aluminum

My 2 cents 

 

[bradp]

So the good news is that there was as Cody and others alluded to a small speck of grease that had pooped itself out. Not sure how long it was there but worked its way from the inside of the spinner and $hat itself across the blades. Cleaned it up, ran it up. Clean. Test flew and clean again. Flew back home 2hrs this morning and still clean. I'm going to have the prop resealed when the plane goes in for hail repair and repaint this winter.

Thank you all for your help in dealing with this. It's unbelievable what a helpful and accommodating Internet community we have. I got PMs with cell phones from members offering any assistance if needed / stuck. You are great resources and I learn a ton every time I post a question.

Take care,

Brad

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