The amount of grease that should be applied to a wheel bearing is enough grease so that the grease fills the wheel bearings and comes out of the wheel bearing which means that you should fill the wheel bearing space around 30 percent to 50 percent full.
For deep groove ball bearings they should be 25 percent to 35 percent full of grease.
The best way to grease wheel bearings is to use a wheel bearing grease tool, where you place the wheel bearing inside the wheel bearing greaser and then use a grease gun to pump grease into the tool and bearing.
Once you notice grease coming out of the wheel bearing then you have put enough grease in the wheel bearing.
Wheel bearings should be greased every 10,000 miles to 12,000 miles although some wheel bearings may go longer.
Some wheel bearings may need to be greased and repacked once a year or every few years depending on how fast the miles rack up on the wheel bearings.
Greasing and repacking the wheel bearings helps prevent corrosion buildup and wear and extends the life of the wheel bearings.
If you have a boat trailer you may need to grease the wheel bearings more often to ensure no water that can get into the hubs remains in the hubs and causes rust and seizing of the bearings.
The grease that you use for wheel bearings is a wheel bearing grease or a multipurpose NLGI #2 or #3 grease.
Even lithium complex grease can also work well for wheel bearings, although any wheel bearing grease will do and you can find wheel bearing grease in tubes for grease guns or in tubs at any automotive parts store, Walmart, online or even at TractorSupply.
Lucas makes a good wheel bearing grease and red greases are best for wheel bearings but any wheel bearing grease is fine.
For wheel bearings that require grease Lucas wheel bearing grease or Valvoline wheel bearing grease is the best lubricants for wheel bearings.
Synthetic oil based grease and even Mobil or Mobil 1, SHC 100 is also good for greasing wheel bearings.
Hub oil should last for 3 to 5 years or 30,000 miles to 50,000 miles.
Many over the road semi trucks run at least 100,000 miles before changing the hub oil.
The hub oil should remain in the hubs for all that time unless a wheel hub seal goes bad and leaks the hub oil out.
It's best to check the hub oil level and seals at least every few months to 6 months to ensure that the hub oil isn't leaking out and if the hub seal is bad or going bad it should be replaced.
If the hub oil all leaks out it will eventually cause the wheel bearings to seize up.
If you do a lot of hard braking or towing you may require more frequent changes of the hub oil.
Off road driving or driving in extreme temperatures can also affect the lifespan of the hub oil.
The kind of oil that you put in hubs is 75w 90 gear oil although some hubs may use a 50 W gear oil or other hub oil.
When adding the 50 W or 75w 90 or other gear oil to the hubs you add the oil slowly until the oil touches the full mark on the wheel hub cap.
It can take awhile depending on the size of the wheel hub cap and wheel hub.
After you fill the wheel hub cap with oil to the fill mark, give it a couple of minutes and recheck the oil level and if needed at some more slowly.