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

[DXB]

8 hours ago, carusoam said:

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...

I see your point - I have little hope that this will be a fix. I'm just doing it as a temporizing measure to guard against the grease being near depletion because it's impossible for me to verify the shop has been topping off the hub at recent annuals.  I doubt the present minute leak carries any real risk.  Unless it gets worse, I can probably delay the reseal job until next annual or until it has to come out of service for another reason.  

[Cody Stallings]

18 hours ago, carusoam said:

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-

It’s Ironic you mentioned flowing like water.

Thats just what the Newer #6 look like coming out of a propeller.

Like sticky water, no real lubricant at at all.

[DXB]

So I flew about 20 more hrs without doing anything.  The same blade kept throwing a very scant (barely detectable) amount of grease.  Today I added Aeroshell #5 to the hub carefully per the maintenance manual (fun learning experience, and now I am a proud grease gun owner).  

Grease came out the opposite grease fitting hole with the first pump on both sides.  Does that mean the hub is nowhere close to running out of adequate grease despite the tiny leak- presumably liquifying #6?  I’m gonna just watch it for a while now unless anyone authoritative thinks otherwise. 

[Mike A]

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

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

I am having leaks on my less than 1 year and 50 hr overhauled prop as well.  My trusted mechanic said to wipe it off and see if it wasn’t just the blades settling, which I did and my leak on the front of the blade seems to have gone away, but there is still a small one on the back of the blade throwing grease on my cowl and windshield. 

What is the reality of really fully cycling the prop? I always was told, for example, not to let the RPMs drop below 1500 on the run up cycle. Is there really going to be any damage of my letting it sit in full low RPM pitch for a couple min on the ground?  Any suggestions on how to cycle it to see if it will reseat or reseal before I go and have it repaired?

[carusoam]

Let’s ask the prop guy...

@Cody Stallings question about intentional low Rpm run-up and oil seals... ^^^^

Best regards,

-a-

[Yetti]

9 hours ago, Mike A said:

I am having leaks on my less than 1 year and 50 hr overhauled prop as well.  My trusted mechanic said to wipe it off and see if it wasn’t just the blades settling, which I did and my leak on the front of the blade seems to have gone away, but there is still a small one on the back of the blade throwing grease on my cowl and windshield. 

What is the reality of really fully cycling the prop? I always was told, for example, not to let the RPMs drop below 1500 on the run up cycle. Is there really going to be any damage of my letting it sit in full low RPM pitch for a couple min on the ground?  Any suggestions on how to cycle it to see if it will reseat or reseal before I go and have it repaired?

What grease?  Did it get greased properly? Throwing grease on the windshield is another matter.  No one said let it sit in low RPM.  I pulled all the way down let is cycle down then back up.  Took a few seconds.  Did it twice.   @Cody Stallings will be along to give the professional answer.

Edited June 23, 2019 by Yetti

[Shadrach]

16 hours ago, Mike A said:

I am having leaks on my less than 1 year and 50 hr overhauled prop as well.  My trusted mechanic said to wipe it off and see if it wasn’t just the blades settling, which I did and my leak on the front of the blade seems to have gone away, but there is still a small one on the back of the blade throwing grease on my cowl and windshield. 

What is the reality of really fully cycling the prop? I always was told, for example, not to let the RPMs drop below 1500 on the run up cycle. Is there really going to be any damage of my letting it sit in full low RPM pitch for a couple min on the ground?  Any suggestions on how to cycle it to see if it will reseat or reseal before I go and have it repaired?

It depends. Loading the engine can cause detonation. Pulling the prop at idle power around 1000rpm should not hurt the engine

[Cody Stallings]

I don’t think Cycling the Propeller is going to do much for you.

Its Most likely the Aeroshell #6 behind the blade Orings. When it breaks down to oil, it streaks past the Orings.

 

Might you chasing the #6 out with #5. It’s a much better an thicker grease 

[DXB]

I am updating this topic after Oshkosh, where I talked to a senior person from Hartzell who seemed to have a lot of technical knowledge.

First a recap of my scenario: 

8 year old top prop on an M20c, 700 hrs on prop, always hangared, now continuously throwing a very thin sheen of grease onto the back side of both blades.  The hub was greased with Aeroshell #6 at the factory. I recently tried to add a little #5 grease by the maintenance manual instructions and found grease came out the other side with the first pump - the written instruction here is to stop pumping the moment grease comes out the other end, or after 6 pumps, whichever comes first.  

Points from my discussion with Hartzell rep:

1. The reported problem with Aeroshell #6 grease breaking down to a thin oil is very real and a big nuisance for them presently.

2. Seals that are basically in ok condition simply can't hold in this breakdown product of #6 grease

3. As long as it is just the thin oily film that is coming out, it is NOT essential to take off the prop for a reseal job

4. The problem actually may stop on its own after all the #6 is out, but it will take a long time. 

5. He suggested periodically putting #5 grease in the hub to replace it. He told me to use a full 6 pumps into a grease fitting at each end of the hub EVEN IF THERE IS GREASE COMING OUT THE OTHER SIDE.  This is a deviation from the maintenance manual, but the guy seemed to know what he was talking about. 

So basically I'm gonna take his advice and avoid what seems like unnecessary maintenance right now.  

Edited July 29, 2019 by DXB

[Gary0747]

What happens if you cycle the prop with the grease zercs removed?  I would think other than being a bit messy it might be a good way to clear out some of the old #6 grease before adding #5?  Is there any risk to the prop?

[Yetti]

9 hours ago, Gary0747 said:

What happens if you cycle the prop with the grease zercs removed?  I would think other than being a bit messy it might be a good way to clear out some of the old #6 grease before adding #5?  Is there any risk to the prop?

I vote NOPE.    After putting #5 in at annual.  Seem to have slowed down the flow of the film.  And doing the deep cycle.

[Shadrach]

17 hours ago, DXB said:

I am updating this topic after Oshkosh, where I talked to a senior person from Hartzell who seemed to have a lot of technical knowledge.

First a recap of my scenario: 

8 year old top prop on an M20c, 700 hrs on prop, always hangared, now continuously throwing a very thin sheen of grease onto the back side of both blades.  The hub was greased with Aeroshell #6 at the factory. I recently tried to add a little #5 grease by the maintenance manual instructions and found grease came out the other side with the first pump - the written instruction here is to stop pumping the moment grease comes out the other end, or after 6 pumps, whichever comes first.  

Points from my discussion with Hartzell rep:

1. The reported problem with Aeroshell #6 grease breaking down to a thin oil is very real and a big nuisance for them presently.

2. Seals that are basically in ok condition simply can't hold in this breakdown product of #6 grease

3. As long as it is just the thin oily film that is coming out, it is NOT essential to take off the prop for a reseal job

4. The problem actually may stop on its own after all the #6 is out, but it will take a long time. 

5. He suggested periodically putting #5 grease in the hub to replace it. He told me to use a full 6 pumps into a grease fitting at each end of the hub EVEN IF THERE IS GREASE COMING OUT THE OTHER SIDE.  This is a deviation from the maintenance manual, but the guy seemed to know what he was talking about. 

So basically I'm gonna take his advice and avoid what seems like unnecessary maintenance right now.  

Use caution Dev. The aluminum hub that your Hartzell utilizes only has outer seals located at the blade shanks. If you keep pumping grease into those zerks the hub will eventually fill with grease. The movement of the piston in the hub will pressurize said grease and herniate the seals.  That is one way to “solve” your problem but I’m sure not what you had in mind.  I hope you’re getting good advice, but if he did not warn you of this possibility, I would be skeptical. I’ve seen this type of mx induced failure before. My prop shop gave me a tour and showed in great detail how this happens. I know your guy is a Hartzell employee, but what’s his position? His advice reads a bit suspect.

@Cody Stallings care to ring in?

i could see increasing service intervals while the prop is still leaking. Trying to pump the old stuff out in one sitting seems like bad advice.

Edited July 30, 2019 by Shadrach

[DXB]

1 hour ago, Shadrach said:

Use caution Dev. The aluminum hub that your Hartzell utilizes only has outer seals located at the blade shanks. If you keep pumping grease into those zerks the hub will eventually fill with grease. The movement of the piston in the hub will pressurize said grease and herniate the seals.  That is one way to “solve” your problem but I’m sure not what you had in mind.  I hope you’re getting good advice, but if he did not warn you of this possibility, I would be skeptical. I’ve seen this type of mx induced failure before. My prop shop gave me a tour and showed in great detail how this happens. I know your guy is a Hartzell employee, but what’s his position? His advice reads a bit suspect.

@Cody Stallings care to ring in?

i could see increasing service intervals while the prop is still leaking. Trying to pump the old stuff out in one sitting seems like bad advice.

Hartzell’s own literature indicates that its impossible to exchange one grease with another with more than 30pct efficiency this way, so I’m not sure that’s what he had in mind. Getting rid of the thin breakdown product of #6 may be another story though.  The risk of overdoing it here seems to be that I might trash the seals for good and need a reseal job immediately. But right now it looks like I need a reseal job, so that may be a tolerable risk.

[Cody Stallings]

3 hours ago, Shadrach said:

Use caution Dev. The aluminum hub that your Hartzell utilizes only has outer seals located at the blade shanks. If you keep pumping grease into those zerks the hub will eventually fill with grease. The movement of the piston in the hub will pressurize said grease and herniate the seals.  That is one way to “solve” your problem but I’m sure not what you had in mind.  I hope you’re getting good advice, but if he did not warn you of this possibility, I would be skeptical. I’ve seen this type of mx induced failure before. My prop shop gave me a tour and showed in great detail how this happens. I know your guy is a Hartzell employee, but what’s his position? His advice reads a bit suspect.

@Cody Stallings care to ring in?

i could see increasing service intervals while the prop is still leaking. Trying to pump the old stuff out in one sitting seems like bad advice.

It is impossible to chase out every drop of #6 using #5.

however you can get the biggest portion of #6 out now that it’s an oil.

You also wanna follow the 115N Manual guidance on how to grease the propeller.

you can fill the hub with grease if not performed properly 

[M20S Driver]

My IA was advised by a prop shop not to lubricate the Hartzell 3 bladed prop on my Mooney Eagle since it is older than 7 years!    I called Hartzell and talked to the rep and he stated that I have to lubricate the prop but not to overfill by opening the secondary port in the back.   My IA decided to go with Hartzell's recommendation and lubricated it conservatively (three pumps of Aeroshell 6 versus 5 pumps).   Is there any reason not to lubricate an old prop?  

[carusoam]

S driver....

You have a mechanical device right?

If you don’t lube it, when the maintenance manual says you should...  the way you should, with the material you should....

 

What would you expect to have happen?

 

I simply expect you mis-understood what somebody was saying to you... If you can, ask that person to explain it one more time...

It may take saying... slow down a bit...

Get maintenance procedure for your prop...

Call Hartzell if you need to...

Over lubing a prop can be done on any plane... this isn’t a Hartzell thing...

Using the proper lube has some recent challenges... still not a big hurdle.... but pushing out thick gooey old lube with thin less gooey new lube is a mismatch in viscosity challenge....
 

If you need more info... we have a prop guy around here...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Guest]

5 hours ago, M20S Driver said:

My IA was advised by a prop shop not to lubricate the Hartzell 3 bladed prop on my Mooney Eagle since it is older than 7 years!    I called Hartzell and talked to the rep and he stated that I have to lubricate the prop but not to overfill by opening the secondary port in the back.   My IA decided to go with Hartzell's recommendation and lubricated it conservatively (three pumps of Aeroshell 6 versus 5 pumps).   Is there any reason not to lubricate an old prop?  

Search for Hartzell manual 115, it contains all the instructions you need.  The prop shop may have meant to not grease your prop with the new grease that Hartzell is using now.  It is not to be mixed with Aeroshell 5 or Aeroshell 6 grease.  You can still grease with these if your prop is an older overhaul.

Clarence

[M20S Driver]

 

4 hours ago, M20Doc said:

Search for Hartzell manual 115, it contains all the instructions you need.  The prop shop may have meant to not grease your prop with the new grease that Hartzell is using now.  It is not to be mixed with Aeroshell 5 or Aeroshell 6 grease.  You can still grease with these if your prop is an older overhaul.

Clarence

Thanks Clarence.  The shop was very clear about the grease types and the service bulletin.  The  point they were making was that the Hartzell manual procedures are written mostly for the life of the prop which is 7 years.   After applying the grease for 7 years the cavity is near full and additional grease may cause more damage than not adding more grease.  When I challenged that, I was told that I am not following the Hartzell manual by using the prop past 7 years and why would I follow the lubrication requirement in the manual?

I have read this post and watched the Hartzell youtube videos and find it difficult to see how the seals are damaged by lubrication if it is done correctly.  That's why I am asking the experts to see if I missed anything?

[FloridaMan]

On 4/8/2019 at 12:43 PM, Cody Stallings said:

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.

 

Funny that it's -40C as that is that the particular temperature is the same value in Fahrenheit. I'm curious how cold prop grease really gets in cruise flight with hot oil being pumped into the hub and there being at least some heat conducted into the roots of the prop blades. 

[RobertGary1]

At last reseal (had to have it dissembled due to an engine failure that ran metal through the system) they packed it with #5 and gave me a cockpit sticker that says flight below -40C prohibited.  
 

-Robert 

[M20S Driver]

13 hours ago, carusoam said:

I simply expect you mis-understood what somebody was saying to you... If you can, ask that person to explain it one more time...

It may take saying... slow down a bit...

There was no misunderstanding.  What the shop was saying was very clear but not correct per Hartzell.   

The intention of my post here was to see if there were any other reason that a prop shop would make such a recommendation.  The only thing that comes to my mind is that there will be more prop overhaul business if people just follow the "expert" opinion

[Cody Stallings]

8 hours ago, FloridaMan said:

Funny that it's -40C as that is that the particular temperature is the same value in Fahrenheit. I'm curious how cold prop grease really gets in cruise flight with hot oil being pumped into the hub and there being at least some heat conducted into the roots of the prop blades. 

There is Zero Heat being pumped into the propeller hub via oil. 
There is no flow of oil to speak of at the propeller. Just oil moving back an forth between the Governor an the propeller.

When you remove a CS prop in most cases you will notice a grey sludge in the Crankshaft an in the Bore of the hub. That’s centrifuged oil that been there for yrs.

Other wise the oil would be the same color as what’s on your dipstick.

can also try this:

You can pull your spinner off after a flight an put your hand on the cylinder of the propeller, then put your other hand on the case halves or even the oil cooler.

At that point you will see what I mean. 

[FloridaMan]

Just now, Cody Stallings said:

There is Zero Heat being pumped into the propeller hub via oil. 
There is no flow of oil to speak of at the propeller. Just oil moving back an forth between the Governor an the propeller.

When you remove a CS prop in most cases you will notice a grey sludge in the Crankshaft an in the Bore of the hub. That’s centrifuged oil that been there for yrs.

Other wise the oil would be the same color as what’s on your dipstick.

can also try this:

You can pull your spinner off after a flight an put your hand on the cylinder of the propeller, then put your other hand on the case halves or even the oil cooler.

At that point you will see what I mean. 

I thought that grey sludge was lead build up from leaded fuel that’s contaminated the oil over the years and centrifuged out inside of the crankshaft. I guess I was wrong. 

[Guest]

9 minutes ago, FloridaMan said:

I thought that grey sludge was lead build up from leaded fuel that’s contaminated the oil over the years and centrifuged out inside of the crankshaft. I guess I was wrong. 

I tend to agree with you, that the sludge inside the crankshaft is dirt and lead carried in suspension in the oil, then centrifuged out of the oil.

While I’m no expert I’ve installed more than one propeller over my career, in most cases this is done with an oil change.  If there were no flow of oil other than what is required to fill the prop, how did dirt and lead get into the crankshaft? 
 

Clarence

[carusoam]

10 hours ago, M20S Driver said:

 

Thanks Clarence.  The shop was very clear about the grease types and the service bulletin.  The  point they were making was that the Hartzell manual procedures are written mostly for the life of the prop which is 7 years.   After applying the grease for 7 years the cavity is near full and additional grease may cause more damage than not adding more grease.  When I challenged that, I was told that I am not following the Hartzell manual by using the prop past 7 years and why would I follow the lubrication requirement in the manual?

I have read this post and watched the Hartzell youtube videos and find it difficult to see how the seals are damaged by lubrication if it is done correctly.  That's why I am asking the experts to see if I missed anything?

SD,

It sounds like you are under the impression that grease goes in, and doesn’t come out...?

That the hub fills up over time...?

When properly greased, the device is full in the places that grease belongs...

When overfilled... grease can escape the seals and flow into places it doesn’t belong...

It goes in one side, flows through the nooks and crannies, and tries to flow out the other side... If the viscosity and chemistries match...the new stuff displaces the old stuff....
 

Changing grease type, or having it get old changes the viscosity.... low viscosity grease (More watery) cannot push out the high viscosity (More thick) grease without tunneling through and leaving the high viscosity crud in place....

Displacement is what is required... this is the process that gets messed up by changing the grease viscosity or chemistry...

Not greasing the prop on schedule...? Because the prop reached TBO? This is possibly a Canadian regulation....?

MSers in Canada have some different rules they need to live with... prop age is one of them...
 

PP thoughts only, not a mechanic...

Best regards,

-a-