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Mobilgrease™ 28

Aircraft component in a factory

Trusted for more than 50 years

Mobilgrease 28 grease – the first synthetic product Mobil™ offered – has been trusted for more than 50 years. With a 10-year shelf life, it offers more than three times the life of similar-type competitive greases.
 
Mobilgrease 28 is the polyalphaolefin (PAO), clay-based multipurpose airframe and wheel bearing grease of choice for many aircraft operators around the world. It is designed to lubricate plain and rolling bearings at low to high speeds, and splines, screws, worm gears and other mechanisms where high-friction reduction, low-wear and low-lubricant friction losses are required.
 
It meets the performance requirements of key military and commercial aviation specifications and offers operators increased flexibility and potential inventory consolidation benefits. Mobilgrease 28 grease is fully approved for use in multipurpose airframe grease applications and in wheel bearings.
 

Why trust in Mobilgrease 28 aviation grease? Because it’s been specifically formulated to:

  • Help airlines maximize inventory value with its 10-year shelf life

  • Deliver exceptional protection against rust and corrosion in equipment

  • Provide optimal load and weight bearing performance, even under extreme heavy load applications

  • Resist deterioration in extreme temperatures and help keep equipment operating at peak performance

Common grease point applications

  • Gears, actuators, jack screws
  • Helicopter rotor bearings
  • General airframe (splines, slats, stabilizers, elevators)
  • Landing gear assemblies
  • Flight controls
  • Aircraft wheel bearings

Product information

Data sheets

Features and Benefits

A particular requirement of aviation greases is the need to resist high temperature stresses, while providing excellent starting and low torque at low-temperature. To meet this combination of needs ExxonMobil product formulation scientists chose synthetic hydrocarbon base oils for Mobilgrease 28 because of their low volatility, exceptional thermal/oxidative resistance, and superb low-temperature capability. Formulators chose specific thickener chemistry and a proprietary additive combination which helps maximize the benefits of the synthetic base oils.

 

Mobilgrease 28 meets the requirements of key military and commercial aviation specifications and has built up a superb reputation for performance and reliability among users around the world.

 

Mobilgrease 28 provides the following advantages and potential benefits:

 

Features

Advantages and Potential Benefits

High viscosity index (VI) synthetic base stock with no wax content

Allows wide operating temperature range - outstanding high and low temperature performance

Provides thicker fluid films protecting against wear of equipment parts operating at high temperature

Causes low resistance during start-up at very low temperatures

Excellent protection against wear and corrosion

Superb bearing protection and helps extend bearing life and reduce bearing replacement costs

Extreme-pressure protection characteristics

Avoids excessive wear, even under shock load

High thermal/oxidative stability

Long relubrication intervals

High resistance to water washout

Maintains excellent grease performance in adverse weather and other water-exposure conditions

 

Applications

Mobilgrease 28 is designed for the lubrication of plain and rolling bearings at low to high speeds, and splines, screws, worm gears, and other mechanisms where high friction reduction, low wear, and low lubricant friction losses are required. The recommended operating temperature range is -54ºC to 177ºC (-65ºF to 350ºF) with appropriate relubrication intervals.

 

Mobilgrease 28 is recommended for use in landing wheel assemblies, control systems and actuators, screw jacks, servo devices, sealed-bearing motors, oscillating bearings, and helicopter rotor bearings on military and civil aircraft. Subject to equipment manufacturer approvals, it can also be used on naval shipboard auxiliary machinery and where superseded specifications MIL-G-81322 (WP), MIL-G-7711A, MIL-G-3545B, and MIL-G-25760A are recommended.

 

Mobilgrease 28 is also recommended for industrial lubrication, including sealed or repackable ball and roller bearings wherever extreme temperature conditions, high speeds, or water washing resistance are factors. Typical industrial applications include conveyor bearings, small alternator bearings operating at temperatures near 177ºC (350ºF), high-speed miniature ball bearings, and bearing applications where oscillatory motion, and vibration create problems.

 

Mobilgrease 28 is qualified by the U.S. Military under Specification MIL-PRF-81322, General-Purpose, Aircraft, and Specification DOD-G-24508A (Navy) for shipboard auxiliary machinery. It is a U.S. Military Symbol WTR and NATO Code Number G-395 grease.

 

Specifications and Approvals

This product has the following approvals:

NATOG-395

MIL-PRF-81322G

 

This product is recommended for use in applications requiring:

DOD-G-24508 A AMENDMENT 4

 

Properties and Specifications

Property

 

Grade

NLGI 1.5

Base Oil Viscosity of Greases @ 100 C, mm2/s, AMS 1700

5.7

Base Oil Viscosity of Greases @ 40 C, mm2/s, AMS 1697

29.3

Bomb Oxidation, Pressure Drop, 100 h, kPa, ASTM D942

PASS

Color, Visual

Dark Red

Copper Strip Corrosion, 24 h, 100 C, Rating, ASTM D4048

1B

Dirt, # particles 25u to 74 u, FTM 3005

Pass

Dirt, # particles 75u or larger, FTM 3005

0

Dropping Point, °C, ASTM D2265

307

Evaporation Loss, 22 h, 177 C, mass%, ASTM D2595

6

Falex Block on Ring Oscillating Wear Scar, 35k cycles, 90 deg angle, Al/bronze block, mm, ASTM D3704

PASS

Four-Ball Wear Test, Scar Diameter, mm, ASTM D2266

0.6

Load Carrying Capacity, Load-Wear Index, kgf, ASTM D2596

40

Low Temperature Torque, Running @ -54 C, 60 min, Nm, ASTM D1478

0.05

Low Temperature Torque, Starting @ -54 C, Nm, ASTM D1478

0.43

Lubrication Life @ 177 C, h, ASTM D3336

PASS

NBR-L, AMS 3217/2 Compat, 70C 158 h, vol %, FTM 3603

6

Oil Separation, 30 h @ 177 C, mass%, ASTM D6184

3.5

Oxidation Stability, Pressure Drop, 500 h, kPa, ASTM D942

PASS

Pen Worked X 100,000, 1/16" holes, 0.1 mm, FTM 313

303

Penetration, Worked, 60X, 0.1 mm, ASTM D217

293

Rust Protection, 48 h @ 125 F, Rating, ASTM D1743

PASS

Texture, VISUAL

Smooth, buttery

Thickener, wt%, AMS 1698

Clay

Water Washout, Loss @ 41 C, wt%, ASTM D1264(mod)

1

 

Health and safety

Health and Safety recommendations for this product can be found on the Material Safety Data Sheet (MSDS) @ http://www.msds.exxonmobil.com/psims/psims.aspx

Boeing
Airbus
Maximize component life
Resists degradation
Extended temperature range
High temperature stability
Water resistance
Wear protection
Load carrying capabilities
Friction control
Military use
Anti-wear grease
Wax-free
High viscosity
Wheel bearing grease
Multi-purpose airframe grease
MIL-PRF-81322G
DOD-G-24508A, Amendment 4
NATO G-395
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