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Greasing a constant speed prop

Ed_Wischmeyer

Well Known Member
My A&P was having trouble putting grease into the two back fittings of the constant speed prop because of the spinner backplate. Are there any funny fittings that make that easier?

Thanks!
 
You don't grease the back fittings, just remove them.

From Hartzell Manual:

B. Aluminum Hub Propellers
(1) Remove the lubrication fitting caps from both sides of the hub assembly.
Remove the lubrication fittings from either the cylinder side, or engine side of
the hub assembly.
NOTE: It is preferable to apply grease to the fitting located nearest the
leading edge of the blade on a tractor installation, or nearest the
trailing edge on a pusher installation. Greasing at this location
reduces the possibility of grease bypassing the bearing area and
entering the hub cavity.
(2) To prevent pressurization of the bearing cavity, use a piece of safety wire to
loosen any blockage or hardened grease at the threaded holes where the
lubrication fittings were removed
 
To make it easier to remember which zerks to remove, Hartzell now allows you to remove and discard the two zerks that get removed to allow old grease out, and replace them with plugs. The parts cost less than the shipping.
 
To make it easier to remember which zerks to remove, Hartzell now allows you to remove and discard the two zerks that get removed to allow old grease out, and replace them with plugs. The parts cost less than the shipping.

Called Hartzell, and Bob and Walt are correct. Thanks! And the prop manual is on the Hartzell web site. (My prop is an experimental prop).

The plugs are $1.05, and Hartzell has a $20 minimum, but Hartzell referred me to a local prop shop.

The advantage of putting in plugs is that they are more robust than the zerk and less prone to breaking on removal.
 
Always grease from leading edge to the trailing edge on a tractor prop installation. (Pusher props go the other way I think). It’s helpful to pull the plugs and dig abound in there with a piece of safety wire to loosen the hardened grease if there’s any that got hard. Your mechanic should know this and lubricant as per the manual.
 
To make it easier to remember which zerks to remove, Hartzell now allows you to remove and discard the two zerks that get removed to allow old grease out, and replace them with plugs. The parts cost less than the shipping.

And new Hartzells are being delivered with plugs in the trailing edge holes now, so its hard to screw up.....
 
Often I find mis-greasing or putting too much grease in a prop hub causes more problems than it solves. The big o-rings around the blades ride on "teflons" and too much grease causes the orings to open up and allow grease to spit out. Also causes balance issues.

If its not leaking grease, then there's no reason to grease it.

All the Hartzells I've opened up have grease in them that looked new.

The movement of the bearing balls is 1/8" at the most so the bearing assembly doesn't rotate enough to effectively distribute grease anyway.

Since it is a sealed system there are virtually no problems with grease contamination. Contrast that with the open bearings on a Hamilton Standard prop. Those require yearly maintenance of the pitch change bearings.
 
One other thing: new Hartzels come with a new grease, which is a bit hard to find. The new grease is NOT compatible with Aeroshell 5/6 so do not switch to the new grease unless you can completely clean the hub first.
 
1 oz. only

Also, from a Hartzell Service Bulletin HC-SL-61-366 I read these CAUTIONS:

CAUTION 3: DO NOT ATTEMPT TO PUMP MORE THAN 1 FL. OZ. (30 ML) OF
GREASE INTO THE LUBRICATION FITTING ON AN ALUMINUM
HUB PROPELLER. USING MORE THAN 1 FL. OZ. (30 ML)
OF GREASE COULD RESULT IN OVER SERVICING OF THE
PROPELLER. VERIFY THE OUTPUT OF THE GREASE GUN
BEFORE SERVICING THE PROPELLER.

CAUTION 4: OVER LUBRICATING AN ALUMINUM HUB PROPELLER MAY
CAUSE THE GREASE TO ENTER THE HUB CAVITY, LEADING TO
EXCESSIVE VIBRATION AND/OR SLUGGISH OPERATION. THE
PROPELLER MUST THEN BE DISASSEMBLED TO REMOVE THIS
GREASE.

I copied and pasted them here verbatim...must be important.
 
One other thing: new Hartzels come with a new grease, which is a bit hard to find. The new grease is NOT compatible with Aeroshell 5/6 so do not switch to the new grease unless you can completely clean the hub first.

Bob do you know if this is recent development? Mine is only about 2 years old and it came with Aeroshell 6 in and the manual says to use #6.
 
Bob do you know if this is recent development? Mine is only about 2 years old and it came with Aeroshell 6 in and the manual says to use #6.

Straight from Hartzell:

Beginning January 6, 2020, NYCO GN3058 is the preferred grease for Hartzell propellers. As of this date, all new production Hartzell propellers will ship with NYCO GN3058 grease. Prior to this change, Aeroshell 6 “all purpose” grease was used on all Hartzell new production propellers manufactured since 1989. (Exception: propellers installed on the Piaggio P180 and the Grob Egrett.)

A label is normally applied to the propeller to indicate the type of grease used. The same grease type must be used during re-lubrication unless the propeller has been disassembled and the old grease removed. NYCO GN3058 is not compatible with any of the approved Aeroshell greases. Do not mix different greases within a propeller.

Complete details can be found in Hartzell Service Letter HC-SL-61-366.

Looks like Spruce is carrying the Nyco grease now. 2 1/2 times more expensive than Aeroshell 6. Must be better, right? ;)
 
This is what I absolutely despise about the (a negative) influence of the certified and legal system here - the reason: we want to change the grease.

Why - is there a problem? Does it last longer? Is durability better? Lifetime fill?

Hartzell can not even say it is better because our product/grease would be "design deficient" and open to litigation. Fact: This is one reason aircraft engine companies don't even think about evolving to a better engine. It has been eliminated from their culture. Maybe "Experimental" growth will change this and give us better, not just cheaper, or less reliable products.
[sorry, rant = off]

OK a little research. It is the latest grease for Airbus wheel bearings. "lithium complex thickened synthetic grease" High temps (175C) and low water washout. I wonder what the 3 ball test results are? Anybody?

Maybe we can use for our props AND wheel bearings. FYI here is a KitPlane article on grease. It has one error - MobilSHC100 is available in tubes from Grainger for less than $8.
 
Last edited:
Straight from Hartzell:

Beginning January 6, 2020, NYCO GN3058 is the preferred grease for Hartzell propellers. As of this date, all new production Hartzell propellers will ship with NYCO GN3058 grease. Prior to this change, Aeroshell 6 “all purpose” grease was used on all Hartzell new production propellers manufactured since 1989. (Exception: propellers installed on the Piaggio P180 and the Grob Egrett.)

A label is normally applied to the propeller to indicate the type of grease used. The same grease type must be used during re-lubrication unless the propeller has been disassembled and the old grease removed. NYCO GN3058 is not compatible with any of the approved Aeroshell greases. Do not mix different greases within a propeller.

Complete details can be found in Hartzell Service Letter HC-SL-61-366.

Looks like Spruce is carrying the Nyco grease now. 2 1/2 times more expensive than Aeroshell 6. Must be better, right? ;)

This was the label on my prop. I ordered it October 2019 and it was delivered January 2020.
 

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You don't grease the back fittings, just remove them.

From Hartzell Manual:

B. Aluminum Hub Propellers
(1) Remove the lubrication fitting caps from both sides of the hub assembly.
Remove the lubrication fittings from either the cylinder side, or engine side of
the hub assembly.
NOTE: It is preferable to apply grease to the fitting located nearest the
leading edge of the blade on a tractor installation, or nearest the
trailing edge on a pusher installation. Greasing at this location
reduces the possibility of grease bypassing the bearing area and
entering the hub cavity.
(2) To prevent pressurization of the bearing cavity, use a piece of safety wire to
loosen any blockage or hardened grease at the threaded holes where the
lubrication fittings were removed

I have found it easier to trim the end of a zip tie to form a narrow plastic spatula to clear out the grease from the aft holes. It allows me to ensure that I'm scooping out old grease rather than just pushing it outward and compressing it against more old grease.
 
Also, from a Hartzell Service Bulletin HC-SL-61-366 I read these CAUTIONS:

CAUTION 3: DO NOT ATTEMPT TO PUMP MORE THAN 1 FL. OZ. (30 ML) OF
GREASE INTO THE LUBRICATION FITTING ON AN ALUMINUM
HUB PROPELLER. USING MORE THAN 1 FL. OZ. (30 ML)
OF GREASE COULD RESULT IN OVER SERVICING OF THE
PROPELLER. VERIFY THE OUTPUT OF THE GREASE GUN
BEFORE SERVICING THE PROPELLER.

CAUTION 4: OVER LUBRICATING AN ALUMINUM HUB PROPELLER MAY
CAUSE THE GREASE TO ENTER THE HUB CAVITY, LEADING TO
EXCESSIVE VIBRATION AND/OR SLUGGISH OPERATION. THE
PROPELLER MUST THEN BE DISASSEMBLED TO REMOVE THIS
GREASE.

I copied and pasted them here verbatim...must be important.

The manual says 6 pumps should be about 30ml of grease. I tried it and took about 40 pumps to get to 30ml. I tried a different grease pump I have at home and same thing. Is there such thing as an aircraft grease pump that delivers more per pump? I don’t want to give it 40 shots and accidentally over grease
 
Several posts have referenced delivery of “new props” from Hartzell. Does any one know when the date is they started this application of installing the plugs. ?
 
Several posts have referenced delivery of “new props” from Hartzell. Does any one know when the date is they started this application of installing the plugs. ?

Read post #13.
SERVICE LETTER HC-SL-61-366 Has an effective date of January 6, 2020.
 
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