Which grease for wheel bearings

Although these bearings can reduce the amount of friction between the moving parts, the bearings must be lubricated periodically to enable maximum life of the assembly. This raises the question as to which lubricant should be used to lubricate, protect and ensure the bearing will provide trouble-free service for an extended period of time. Oils have been employed in many hub assemblies with good results. When using an oil bath to lubricate the wheel ends, there is generally less drag on the bearings when compared to grease lubrication.

The oil is applied either directly to the hub via a fill port or supplied internally from the differential utilizing a piping mechanism. In both cases, maintaining the correct oil level and selecting the appropriate oil are key to preserving the bearing and ensuring that the hub functions properly.

Bearings that share oil from the differential will commonly be lubricated with gear oil. Even hubs that are splash lubricated in their own individual bath may be lubricated with an approved gear oil. While most people may be familiar with gear oils, the ones used in automotive applications are slightly different than those for industrial applications, which have their own designations and viscosity grade systems.

For drive wheel ends, where the oil is shared between the hub and the axle, this becomes very important, as the oil will be lubricating a gear set as well as a bearing set. The most current and widely used is GL This designation is employed with most hypoid gear sets and has standard performance levels listed in the ASTM D specification. Other tested parameters include foam stability, rust protection, and thermal and oxidative stability.

The full range of gear oil designations span from GL-1 through GL The only active designations are GL-4 and GL GL-4 is utilized in many manual transmissions and transaxles. These tend to be used more at lower speeds and loads when compared to GL The other designations are considered inactive and usually are not recommended in these applications.

Breaking the mold is the MT-1 designation, which is frequently employed in non-synchronized manual transmissions. These oils are more specialized, and care should be taken to prevent accidentally mixing these with other fluids. In order for a lubricant to meet these specifications, there must be a healthy dose of additives to fortify the base oil.

The most common additives in these types of fluids are antioxidants, viscosity index improvers and extreme-pressure EP additives. Some EP additives contain active sulfur phosphorus, which can be corrosive to softer metals, so always check your equipment manual before selecting and using any oil for your particular application.

In addition to the oil designation, you must also choose the proper oil viscosity to replace or refill the system. You may start to hear a rhythmic thumping noise that sounds like a card that's stuck on the spokes of a rotating wheel. The noise gets louder the more the bearings wear out. Dropping point refers to the temperature at which the grease changes from its semi-solid state to a liquid state.

Most greases have the recommended dropping point of degrees Fahrenheit. Each bearing grease type comes with a numerical rating that indicates its thickness. Bearing grease comes in a wide variety of thicknesses. The numerical rating helps you pick the best one for your application.

Most commonly, the numerical rating ranges between 0 and 6. The 0 rating indicates that the grease is soft, in an almost liquid-like consistency. Most wheel bearing formulas come with a rating of 2. This indicates that the consistency is similar to peanut butter. You can mix together some oils used in bearing grease. For example, plant-based oil and petroleum-based oil can mix freely with each other.

If you want to know if the new bearing grease will mix well with the old bearing grease, you can do some research. If you mix together two incompatible types of grease, your wheel bearings can fail. Mixing together two different types of soap can result in the soap separating from the oil. This will render the grease useless. That means thoroughly removing the old grease before packing the new grease into the wheel bearings. Here are some liquids you can use to clean out the old grease:.

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