Hi All -

Question. Are w140 front wheel bearings problematic, or do they require routine maintenance and inspection?

My brother drives a '97 S320 that has been in the family since new. It has about 50K miles on it. Last week one of the front bearings failed and welded itself to the spindle. Ever hear of this kind of failure before, or at such low miles?

To add a bit of drama, it went out while he was driving his wife to the hospital to have a baby!

Anyways, all is well now. The knuckle was replaced - spindle was ruined. New pads and rotors - it had never had brake work. For good measure the mechanic insisted on checking and repacking the bearings on the other side as well.

- JimY

jc,


I thought all post 86 cars came with wheel bearings packed with special mercedes grease which meets(mil-spec? 21733). I looked an equivlent up as "mobil 28" but didn't persue it- just got a tube from Mercedes.
I've never had a bearing seize on my cars. I'd definately do a sanity check on wheel bearing play when rotating tires or just when the front-end is in the air.
I think wheel brg play measured with a dial-indicator is 0.01-0.02 mm.
They should go a long time without service....

Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

ANY bearing will fail if installed incorrectly. This is most often the case when you have backyard mechanics who still don't know proper bearing handling methods. (I've been guilty of it myself in my earlier days). In fact, there are a lot of certified mechanics who don't know how to work with bearings. I know this from personal experience with my mother's car. I work in the bearing industry and we hear these horror stories every day.

To have the bearing weld itself to the spindle and ruin it, your brother must've driven the car some distance after the onset of damage.

Michael is correct, the bearing play is critical. The very least you can do is check for bearing movement when the wheel is off.

__________________
95 E320 Cabriolet, 159K

Kestas mentions "if installed incorrectly"--but JimY, don't I understand you to say there's never been brake work done, and the bearings haven't been touched before?

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)