Wheel Bearing Grease Question

[dwurfel]

Going to change both mains this weekend and they needed it. Definitely uneven wear on the inside of both.
These tires had about 375 hours on them.

My question is I will be repacking and lubing bearing and am planning to use high temp automotive wheel bearing grease.
In reviewing some other comments online this seems to be a satisfactory option. Wondering what the thoughts are here are here and experiences with your Diamonds. Safe Flying!

[krellis]

If you are asking if automotive wheel bearing grease will perform properly in this application - then the answer is probably yes, depending on the grease used.

If you are asking if it's permissible to use automotive grease in this application - then I believe the answer is no.

From the DA40 AMM -

CAUTION: DO NOT MIX AVIATION WHEEL BEARING GREASES WITH EACH
% OTHER. IF USING OTHER APPROVED GREASES, COMPLETE
% REMOVAL OF CONTAINED GREASE AND BEARING CLEANING IS
% REQUIRED. REPLACEMENT OF PREVIOUSLY LUBRICATED FELT
% GREASE SEALS IS ALSO REQUIRED.
% (5) The wheel manufacturer lubricates the main wheel bearings with Mobil Aviation Grease SHC 100.

If you are operating under an experimental certificate, then you can do pretty much as you please.

Wheel bearing grease is specified as "Type 1" in the Lubricant Specifications table of the AMM - which limits you to a couple of choices. Mobil SHC 100 or Aeroshell 22 are synthetic greases and widely available in the States. Aeroshell 5 is considered an obsolete choice.

[Steve]

David:

That is precisely what I do. After 17 years, the bearings and races appear brand new.

Steve

[dwurfel]

Just made my order to Aircraft Spruce and also ordered one of those packing tools. Finally tired of getting more grease on me than the bearing. Thank you,thank you for the advise. Gotta tell you I talk glowingly about all the help I have gotten from fellow Diamond owners like yourselves.

[smoss]

Keith- why do you say AeroShell 5 is an obsolete choice? Still readily available and does not separate in warm temps. It is what I have always used. The "obsolete" in the AMM only refers to the MIL-G-3545 spec.

[krellis]

Keith- why do you say AeroShell 5 is an obsolete choice? Still readily available and does not separate in warm temps. It is what I have always used. The "obsolete" in the AMM only refers to the MIL-G-3545 spec.

You are correct. The Mil-spec is obsolete, not the grease. However, it is no longer used by the manufacturer (Cleveland) as they have switched to the synthetic Mobil grease.

I still use Aeroshell 5 on my DA20-A1 wheel bearings, as Diamond has not updated the AMM to include the newer lubrication spec. The C1 has the newer specs, I believe.