Aeroshell Grease 7

Grease Selection and Use

All the efforts of getting the right stuff are negated by inadvertent contamina­tion by careless handling and storage. This can be a vexing problem in a shop environment with multiple users, big containers and people in a hurry Moly or extreme pressure lubes are better suited for low speed high pressure sliding surfaces, as they form a solid film on the parts that resists evaporation, water washout and corrosion.

This can be counter-intuitive some­what, as one might think that this sticky, high pressure stuff is the perfect grease for wheel bearings. It is what you tend to find in the automotive markets as the universal solution.

MIXING
Do you need to clean out the old stuff before using the new? Yes, particularly when changing from an organic based product to an inorganic. There may be adverse chemical reactions that lessen the grease effectiveness.

For example if you switch from Shell 5 to Shell 22, cleaning the bearings becomes particularly important. Even more so in applications such as in prop hubs, where corrosion damage can be very expensive to fix.

When repacking bearings, it’s a good idea to dean them for other reasons as well, such as for inspection of the metal surfaces. Any good solvent will work fine, and as always recommended, don’t spin dry bearings with shop air.

For grease fittings, you are obviously not going to disassemble the joints just to clean out oid grease. The only thing you can do is be sure to run enough new grease into the fitting to displace as much old grease as possible, and stick with one type of grease. Be sure to clean off the old, expelled grease, as it’s not healthy for paint over prolonged periods. And air loads can spread it everywhere.

OUR PICKS
First, look in your aircraft maintenance manual for their recommendations. Nor­mally you will find a chart or diagram with all the fittings/locations and recom­mended lubricant or protectant products. (Some fitting locations may be virtually invisible without a diagram.) Sched­ules for lubrication will also be there. Hopefully, mil-spec. numbers or other references will be included, which makes selection easier, even though mil spec numbers are slowly being discontinued.

Barring specific recommendations from the manufacturer, we like Shell 22 for the wheel bearings of jets/high performance aircraft and Shell 5 for all others in wheel bearing applications.

Shell 5 has the greatest oil viscosity by orders of magnitude over all other Shell greases. Shell 5 is also recommended for magnetos, starters, and generators.

For the grease gun and airframe lube, we like Shell 6. Again, for high perfor­mance aircraft/turbines, Shell 7, with its synthetic base oil, has a greater tempera­ture range both high and low. Shell 7 is Some gun fittings have a twist screw thread that allows a tighter grip to be made on the Zerk. We got ours at a local auto parts store, but it still helps to use hand pressure on the fitting to coax grease into stubborn fittings.

the product recommended by Shell for turbine applications of all types.

If you are determined to use only one grease for all applications, then go with Shell 22, but we strongly recommend you adhere to the recommendations in your maintenance manual first.

Grease has a shelf life of three years according to Shell’s recommendations. After that it may start to break down into its component parts, and may no longer meet its specifications. In case you are operating the latest generation of jet, Shell 33 is a multipurpose, lithium thick­ened with a synthetic oil base designed.

List of current Aeroshell greases and base oils, Note, some other tables in the guide list some of the below as obsolete, but we believe these are all still available from suppliers.

for commercial aircraft, and specifically approved for the Boeing BMS 3-33 specifica­tion.

GEARBOXES AND MOTORS 
While gearboxes generally use specialized fluids, when you are greasing, be sure to check the manual for motor and gearbox servicing require­ments and greases before you start.

On Bonanzas it’s every 300 hours, and not only includes the gear actuator box, but also checking the separate gear mo­tor. Judging from our inspections, these motors are frequency neglected, and gearboxes untouched. Don’t say we didn’t warn you if the gear fails to come down.

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 FRENCH AVIATION SPECIFICATIONS
 RUSSIAN AVIATION SPECIFICATIONS
Grease Selection and Use
BRIEFING NOTE
Boeing and Airbus standardize

AeroShell Grease 7 is an advanced multi-purpose grease,
composed of a synthetic oil thickened with Microgel®, possessing
good load carrying ability over a wide temperature range. It is
inhibited against corrosion and has excellent resistance to water.
The useful operating temperature range is –73°C to +149°C.