It's impossible to overpack bearings, the excess grease just squirts out the other side of the cage. Infact thats how you know they are packed properly and fully.

I am partial to synthetic grease, years ago I had a 280Z racekar that would eat front wheel bearings and spindles on a regular basis. After I tried synthetic the problem went away.

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Karl B
95 E300 D
2006 Mazdaspeed 6
2001 GMC Yukon XL
1997 Contour SVT
Mazda RX-7 SCCA race car

In reality it is not only possible to overpack bearings, but a frequent occurrence and leads to low life due to over heating. The grease works in a ball bearing by reaching a certain temperature and then releasing the oil it has in suspension. The oil forms a hydrodynamic film between the ball and the race, and is subjected to very high, very localized pressures. The film thickness for a given application is ideally thicker than the defects in the surface finish of the balls and races, and any of the grease thickening agents or other additives. The oil also acts to remove heat from the bearing rolling elements and contact areas of the races. As the oil cools the bearing the temperatures drop into a range of acceptable (in a balanced design) temperatures where the grease pack can resupply the oil being lost to evaporation and mechanical destruction on a molecular level, for a regular, repeatable time period.

Overfilling the bearing causes the balls to have to churn the extra grease as they spin, and it adds drag to the cage. This all makes additional heat and makes the normal flow oil less effective as it runs out of the working area and it evaporates sooner, leaving little more than the thickeners and additives, which are not lubricants in most cases. It is well documented that too much grease leads to premature failures from over heating.

Newer greases with better oils and thickeners are probably more tolerant of this condition, but they are not immune either. The tolerance comes from higher temperature grade oils and thickeners, all of which are usually more expensive, and that leads to using less rather than more grease in a bearing repacking more often than not. More is not better when it comes to packing bearings. The right amount is best, and that amount is determined by the bearing size, the bearing housing shape and the loads. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

It is not a closed space, the extra grease works it's way out of the space the first time the wheel is turned and gets the grease hot. Front wheel bearings are tapered roller bearings, there is no possible way that you can over pack them by hand. Most ruined bearings are caused by over tightening, not over packing with grease.

__________________

Karl B
95 E300 D
2006 Mazdaspeed 6
2001 GMC Yukon XL
1997 Contour SVT
Mazda RX-7 SCCA race car

If you mean packing the space between the rollers/races only, you are correct. If you are speaking of the cavity they sit inside of, it is sealed. If you fill the entire cavity at reassembly the grease will not have room to leave the space. The area is sealed to keep dirt and water out, and the grease in. So, the cavity is not without limit. If your method of greasing is to fill the bearing outside the cavity, install it, rotate the hub, and only add grease in the cavity outside the working area, a 100% fill of the bearing itself might be ok.

I would also concur that over tightening is a frequent error. As is loss of cleanliness. But overfilling a bearing cavity when regreasing is also common. It is the primary reason why bearing greasing evolutions on industrial machinery calls for filling a specific grease cup with the desired grease, and using the grease cup to dispense the specified volume of grease. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

One very important point that has not been mentioned here: after packing the bearings, be sure to pack grease in each dust cap up to the flared edge. This is the only thing required by MBZ that is different from any other car.

Need to check the manual to be certain. I haven't seen the procedure on the 210 chassis, but it's likely similar to the others that I've seen. Mercedes specifies a certain amount of wheel bearing grease for the bearing itself and for the grease cap. Usually it's something like 15g and 50g. Maybe filling it up to the flared edge is the right amount, but I've never seen it stated that way in any Mercedes manual.

__________________
Len
'59 220S Cabriolet-SOLD and living happily in Malta
'83 240D 351,500 miles original owner-SOLD
'88 560SL 41,000 miles - totaled and parted out
https://sites.google.com/site/mercedesstuff/home
'99 E300 turbo 227,500 miles
'03 SLK320 40,000 miles - gave to my daughter
'14 Smart electric coupe 28,500 miles
'14 Smart electric cabriolet 28,500 miles
'15 Smart electric coupe 28,000 miles

make sure you use a disc brake rated bearing grease. FWIW, i called Mobil-1's 800#, and they could NOT confirm that they're grease was rated as such. so I use valvoline synthetic.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.