How much greese should be in a bearing??

[frankiee]

My instructor says that I should pack a bearing to only 2/3 or 3/4 full of grease or it could overheat.
I allways thought it should be full.
What do you think the proper amount and proceedure should be
Thanks

 

[XS650]

Even 2/3 seems a bit on the high side but probably OK.

Assuming you are taking about wheel bearings, all it needs is for the rollers to be packed and some extra grease to keep things lubed when the grease melts.
Bearing Packing Instructions

 

[Kestas]

The space between the inner and outer race should be completely packed with grease. That's why the packing instructions tell you to pack the grease between the rollers. The sides of the bearing should be buttered, and all internal cavity surfaces of the hub should be buttered - not filled - with grease.

Mercedes actually specifies an amount of grease to use during packing of a wheel bearing. I believe it's 60 grams. This is to prevent the mechanic from getting overzealous with the grease. Too much grease interferes with heat transfer.

 

[brian fix]

It depends on bearing/cavity,,fill the inside between bearings, and HAND pack roller bearings, but do not over fill (pack) around bearing ,about a half,,use new grease seals always,,,and of course good grease,,remeber ,grease does expand some when at elevated temps and gets semi-soft when hot,BL

 

[widman]

Too much grease overheats from churning and lack of a place to go when it expands from heat, causing more resistance and more heat. I have a graph on my site of the typical increases from overgreasing and how long it takes to come down.

 

[frankiee]

I am gathering that the way to pack a bearing in my hand is to put the grease in my palm and force the greese between the inner and outer race until the bearing is absolutely full of greese. Am I right

 

[Kestas]

Not quite. Bearing packing instructions apply to taper roller bearings, so I'm assuming you're working with taper rollers.

Set aside the outer race. You take the inner ring with the rollers and cage (this is called the cone assembly) and scrape the grease from the palm of your hand with the steel cage, forcing the grease to pack between the rollers until it starts coming out the other end of the rollers. Do this all around the cone assembly. This is what people call packing.

Continue by buttering the outer race and place the cone on it. Add grease on the sides. Now the bearing is properly greased.

The same principles apply for ball- and cylindrical-roller bearings.

I'm apologize if the terminology is confusing.

 

[mechtech]

Volkswagon used to recomend packing the front wheel hubs [roller bearings] full with grease.
I think that heat expansion, and the resultant grease where you don't want it [like brakes] is the reason for using less.

 

[JohnBrowning]

Yes, Frankiee that is correct. Hand packing is best. It is time consumeing but you waste less grease this way. You pack it until the grease pops out the top of the bearing. This forces any old grease out as well. Then the sides are lightly coated with grease. The hub area should not be over filled with grease. In most applications a 1/4 of grease around the inside of the hub is about right. You want flenty of empty space. It is preety normal for people to use too much grease int he hub area. You really can not pack too much grease in between the cage and roller bearing of a bearing. Youcan over butter the outsides though!

 

[JBJ]

If the grease has somewhere to go (air space in the hub, etc) packed full is just fine. The bearing will push enough grease out to be OK. If the grease has no place to go, 30% of the air space in the bearing should be packed with grease. (You will never see a prelubed bearing filled up!)

SKF, ***, Timken, etc, will all give an exact measurement for the cc's or grams of gease to use in a particular bearing. That measurement is enough grease to fill 30% of the air space.

I've been a machinery builder for 25 years, have been to bearing school for Timken, have many times been in contact with SKF tech support to get the exact amount a grease for a particular bearing. SKF will sell you a syringe just for the purpose of getting the right amount of grease.

If a wheel bearing and hub is to be packed full (bearing buddies, etc.) the wheel bearing should be adjusted suprisingly loose.

 

[brian fix]

JBJ is right ,though all bearings need a certain amout of grease, Read my last post use a grease of a higher Timken OK load of at 40#,,,Schaeffers , Mystik ,Lubriplate are really good greases,Amsoil also their general purpose is fine,,,,,,,,,,,dont over grease ,but do not under grease,,,,the proper amount is the most crucial,,,,,,BL