Next step for trace amount of something (grease?) on prop

[DXB]

My first encounter with propeller issues:  I have a Hartzell Top Prop on my M20C that is 8 years old, has ~700 hrs on it, and has never needed major service in the 5 years I've own the plane.  Last November I noticed a little shiny streak on the back side of just one blade that was not greasy to touch.  I buffed it off, and it did not recur.  I mentioned the issue at annual in December and was told that they did not see any evidence of grease leaking from the hub.  Last week, I noticed the same shiny streak appear on the same blade.  I wiped it off, and it appeared again on the next flight yesterday (pic below). I'm wondering if the leak is very small and only is appearing now at warmer temps when the grease is softer.   It is a very small amount of material (not greasy to touch), just on the back side of one blade. I don't see any obvious leak when I peer into where the blade meets the hub.  The blades seem solidly seated and have no play in them whatsoever.

Questions:

(1) What should I do next - observe for a while or take action now and if so what action?

(2) How urgent is dealing with this issue?  Will it destroy my prop if I don't take action immediately and keep flying for the 20-30 more hours I have planned in the next couple months?  Or if I keep flying for up to ~100 hours until my next annual in December?

I am not one to ignore problems, but I also don't want to over-react. From reading on here, it seems like there's a lot of pitfalls to prop maintenance, and @Cody Stallings offers clear and thoughtful advice.  Sadly, his shop may be too far away, so can anyone recommend a good prop shop in the Northeast?  

[Marauder]

Dev - I think you should have it looked at. That is more than I think you should see on the prop. Is it the same on both blades?

I will look in my logs for who has done my prop work over the past 25 years. It is either East Coast Propeller or Sensenich Propeller Services. Both are in Lancaster.


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[MIm20c]

2 blade props are easy to ship. From everything I’ve seen Cody is a straight shooter. I’d pick a time that works well for you and ship it off. 

[DXB]

2 minutes ago, Marauder said:

Dev - I think you should have it looked at. That is more than I think you should see on the prop. Is it the same on both blades?

I will look in my logs for who has done my prop work over the past 25 years. It is either East Coast Propeller or Sensenich Propeller Services. Both are in Lancaster.


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Just one blade, just the backside, just a trace amount.  Yeah was wondering if a trip to Lancaster would be the fastest way to address.

[Cody Stallings]

I would venture a guess that your propeller has been serviced with Aeroshell #6.

The newer #6 has a bad trait of breaking down to a light oil an exiting out around the Blade O-Rings.

I have been screaming at Aeroshell an Hartzell about this Issue for well over a year, as I have had to warranty 14 Propellers that were fresh out of my shop an leaking just like yours. Sadly most were 4 Blade Turboprops that are much more expensive to reseal.

I have moved to Aeroshell #5 for Propellers that do not have De-Ice boots, an I have purchased every container I could find of the Old formulation of #6 for customers who have Anti-Ice capabilities.

 

What you may run into with your propeller, some shops wanna O/H a propeller that is outside of its 5-6 year Factory recommended TBO. Some won’t just perform the service needed. 

A 700hr propeller that lives in a Hanger is far from needing a full O/H.

 

[DXB]

@Cody Stallings thanks very much!  The plane has always been hangared BTW.

Assuming it is  Aeroshell 6 breakdown that you suspect  underlies the leak, how many hours of operation would you think it takes to risk damage to my type and age of prop after first observing the issue?

Secondly,  how long does it typically take to turn around a reseal job on this type of prop in your shop if I get it shipped down to you? 

I realize you can only comment in general, not in relation to my specific situation because you have not examined my prop yet. 

[Shadrach]

1 hour ago, DXB said:

Just one blade, just the backside, just a trace amount.  Yeah was wondering if a trip to Lancaster would be the fastest way to address.

It needs to be lubed and resealed but most shops want to overhaul if your past calendar TBO. I had the same issue. East coast propeller in Lititz, PA would not reseal, strictly Overhaul. Randy made me a deal I couldn’t refuse as his OH quote was pretty close to a reseal quote from distant shops. I think it was $2200 all in.

[PT20J]

Too far away for you probably, but as a price point, I had my McCauley resealed by Northwest Propeller Service in Puyallup WA for $1500 + $120 parts last September. Dick Jacob actually recommended against doing an overhaul unless they found something when they had it apart (they didn't). It came back looking and running like new.

Skip

[Skates97]

I had something very similar show up after a flight last November.

In addition to what he posted in that thread I traded some messages with @Cody Stallings who was a huge help. He gave the same advice as above, no overhaul needed, just a reseal. He said if a local place wouldn't reseal it (12 years since install and 690 hours) to put it in a crate and send it to him.

I kept flying it and watching, 20 hours later and after a five hour flight it had progressed to where I could see more than just the sheen on the blades.

With some very long flights planned for the summer I decided to get it done.

My mechanic recommended Johnson Propeller here in So Cal and I gave them a call asking if they would reseal it even though it was past TBO. After about 20 minutes on the phone answering questions, "No, there's no AD on it, replaced with a B hub in 2007, No, not used, it was a new prop/hub installed in 2007, No, never re-sealed or overhauled before," he said that he would do a reseal on it. The price quoted was $1,100 including pickup and delivery with about a 1 week turn around. My mechanic quoted 2 1/2 hours ($225) to remove and re-install.

Mechanic pulled it on a Tuesday, prop shop picked it up same day and returned it two days later on Thursday. Mechanic didn't get it reinstalled until the next Tuesday because he had other work lined up and the prop came back much sooner than he expected. Prop shop came in under their quoted price at $1,034 and mechanic came in under his quoted price at $180.

So thankful to Cody for sharing his knowledge with me and having the option of sending it to him. Without his advice I probably would have ended up with an overhaul instead of a re-seal and my bank account would be much lighter.

[Cody Stallings]

27 minutes ago, DXB said:

@Cody Stallings thanks very much!  The plane has always been hangared BTW.

Assuming it is  Aeroshell 6 breakdown that you suspect  underlies the leak, how many hours of operation would you think it takes to risk damage to my type and age of prop after first observing the issue?

Secondly,  how long does it typically take to turn around a reseal job on this type of prop in your shop if I get it shipped down to you? 

I realize you can only comment in general, not in relation to my specific situation because you have not examined my prop yet. 

Turn time this time of year is about 1-1.5 week.

As to how long you can run it like it is, I really can’t say.

If you do plan to run it that way for 30-40hrs you may wanna get some #5 an give it a TopOff.

The #6 being Oil now doesn’t really give you a sign of a “real grease leak”.

It will just piss the oil out a little faster than it would the grease.

[FloridaMan]

Every time mine has leaked, I've gotten it resealed and it's only been a couple hundred dollars if I remember correctly (I'm talking about the 2-blade Hartzell on my F -- no telling what the Rocket might cost). 

Just make sure when it's reinstalled that the spinner fits tightly or you may end up with a cracked bulkhead. 

[Yetti]

One thing you can try is to do a full cycle on the prop.   It can reseat things.

[carusoam]

If it were grease from being over filled... it would come out more like small globs and show up looking more like yellowish grease on the blades and top of cowl...

So trying to eliminate other possibilities...

Thanks to Cody, for sharing the pro insight!

Best regards,

-a-

[bradp]

H&H / Triad will do a reseal for about $1200

[M20F]

18 hours ago, Cody Stallings said:

Turn time this time of year is about 1-1.5 week.

As to how long you can run it like it is, I really can’t say.

If you do plan to run it that way for 30-40hrs you may wanna get some #5 an give it a TopOff.

The #6 being Oil now doesn’t really give you a sign of a “real grease leak”.

It will just piss the oil out a little faster than it would the grease.

Is it ok to switch from 6 to 5 without taking apart?  The Hartzell book is fairly emphatic that you can’t switch grease types without taking apart.  Always seemed strange to me.  

[mike_elliott]

19 minutes ago, M20F said:

Is it ok to switch from 6 to 5 without taking apart?  The Hartzell book is fairly emphatic that you can’t switch grease types without taking apart.  Always seemed strange to me.  

It seems you answered your own question. as strange as it may seem to you. Somebody eventually will contradict Hartzell if thats what you want to hear, after all, it is the internet and we all know more than their engineers

 

[Marauder]

It seems you answered your own question. as strange as it may seem to you. Somebody eventually will contradict Hartzell if thats what you want to hear, after all, it is the internet and we all know more than their engineers
 

Except the guy giving us this advice is our prop guy... I’m sure there are some viscosity differences and perhaps an additive difference between the 5 & 6 but it appears the 5 is for higher temp applications.

https://www.shell.com/business-customers/aviation/aeroshell/knowledge-centre/the-aeroshell-book/_jcr_content/par/textimage_1433441235.stream/1445042875796/e76780948490d28fdd9086517026d27c1442a76d/aeroshell-book-5greases.pdf


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[M20F]

55 minutes ago, Marauder said:

Except the guy giving us this advice is our prop guy... 

 

Correct.  There are a lot of things in books we ignore on the basis of updated knowledge.  I am no expert, Cody is so interested in knowing the thoughts. 

[Cody Stallings]

52 minutes ago, M20F said:

Correct.  There are a lot of things in books we ignore on the basis of updated knowledge.  I am no expert, Cody is so interested in knowing the thoughts. 

Yes, you can Mix #5 an #6.

For the small Hartzell on the Mooney’s, you would be doing yourself a favor by lubricating with #5. It sticks to steel parts better an dose not break down.

However it’s not a good idea on Propellers that are Certified into known Ice.

In most cases that would be a long range high flying Turbo Prop. The way the Manuel reads is #6 must be used in a propeller that is capable of operating at -40C. If #5 is put in that propeller the dash has to be placarded for no flight colder than -39C

So, If you don’t plan to operate colder than -39 your good to go.

Personally an professionally speaking, #5 is a far more superior grease than #6.

#6 is the “do-all” grease, you can put it in any propeller without worry. That’s why it comes in every propeller out of the factory.

That was the way of thinking till the new formulation hit the Market an started separating. Now I put #5 in everything I can.

For the Propellers that have to have #6, I have been fortunate enough to secure a large quantity of the older formulation of #6 that doesn’t separate an leak.

 

[mike_elliott]

If Cody says we can do it, I stand corrected. GO for it!!
 

[DXB]

So I called the shop that did my last 3 annuals - they state that they only use #5 grease.  I suspect the very thin sheen I’m seeing is indeed older degrading #6 coming out. It is nothing like the little clumps in @Skates97 ‘s pic. Of course I have no way to validate that my shop actually topped off the hub in December, so I’m asking the guy on my field to do it again now with #5.  I’ll wait until next annual to pull the prop unless the leak gets significantly worse or the plane is down for another reason.  

[DXB]

On 4/7/2019 at 5:55 PM, Yetti said:

One thing you can try is to do a full cycle on the prop.   It can reseat things.

What's an optimal procedure for doing this?  I tried to look up but could not find.

[DXB]

7 hours ago, Cody Stallings said:

#6 is the “do-all” grease, you can put it in any propeller without worry. That’s why it comes in every propeller out of the factory.

Do you happen to know what year the formulation changed for the worse for #6  ?  I'm curious whether my Hartzell from 2011 would have had the new or the old stuff from the factory.

[Cody Stallings]

2 hours ago, DXB said:

Do you happen to know what year the formulation changed for the worse for #6  ?  I'm curious whether my Hartzell from 2011 would have had the new or the old stuff from the factory.

I really don’t know.

I took possession of my first barrel of bad grease in the summer of 17.

 

[carusoam]

Regarding pushing out one type of grease with another...

From a technical point of view...

If the two materials are similar in chemistry and viscosity... there are things to keep in mind...

1) a higher viscosity material can push out a lower viscosity material...as expected...

2) a lower viscosity (watery) material will have difficulty pushing the thicker stuff, and will tend to burrow a channel through it... instead of pushing it out...

3) dissimilar chemistry will keep things from mixing, and aid in the channeling effect...

4) Similar chemistry and similar viscosity will do both... channel and push... by the time you have flushed all the old stuff out, you may have flushed the entire volume available in the country...

5) viscosity is often temperature dependent... that adds an additional challenge to the process...

So... if the manual says disassemble and clean, and you are feeling lucky that day... don’t try the short cut... one viscous fluid is unexpected to be able to flush out the other...  It doesn’t flow at all like water...

PP thoughts only, not a mechanic or prop guy...  shining a light on something that may not be there...

Best regards,

-a-