1) No, wheel bearing failure is quite common. It's almost certainly not an indicator of trouble anywhere else, and it's failure shouldn't make you worry about the rest of your car.
2) Typically, wheel bearings don't wear out as such. They can fail due to seal failure and contaminant ingress as mentioned by Richard, but, by far the majority actually fail via a fatigue mechanism. There are many other failure mechanisms relating to poor materials, and poor lubrication, but most bearings in cars don't fall foul of these issues.
As rolling element bearings typically have very localised contact between bearing and race, very high stresses are developed there. The area of maximum stress is actually just below the surface of the race, and the fatigue failure usually begins there. You can't see it until the crack propagates, and breaks the surface of the race - at which point, the bearing usually becomes noisy.
Here's the fun bit - the bearings can't be designed with an absolutely known and guaranteed life; it's a statistical thing. Once you design or call up a rolling element bearing to be used in an application, you accept that however you size and specify the quality of the bearing, however large a design margin you place on the loading calculations, you WILL have warranty failures.
3) Beyond my knowledge
4) Way beyond my knowledge
5) It depends *exactly* what you asked them to do. Reporting back, and giving you the option seems a reasonable thing for them to have done IMO.
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Thanks, gentlemen. That is most helpful.
I can, by the way, confirm that there has been no noise.
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I would agree with NC that a wheel bearing will usually become noisy before it becomes an MoT failure (presumably as a result of wear causing noticeable play when the wheel is jacked up and rocked vertically). In this case that hasn't happened. Some taper roller bearings are adjustable, and can be tightened up a little to compensate for wear. But non-adjustable double-row ball bearings are not, and have to be replaced.
It isn't an amusing job usually. The difficult bit is the removal of inner or outer races from the wheel hub or hub carrier and the insertion of new ones, which can call for a big bench press. Good mechanics can often improvise, but an amateur can get into trouble with tight interference-fit components. If the bearing is in one piece it will come with lubricant already in it. If it comes apart and has to be assembled in situ, immense care has to be taken to avoid the introduction of any grit or dirt, and to lubricate with the right amount of the right grease.
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Well, just to finish the story, the repair has been done.
RichardW gave some good advice when he wrote "I would expect the cost to be at least twice the cost of an independant though, so would avoid it like the plague."
Alas, I had already agreed for the dealer to do the work, and it came to . . . £177.03. Ouch.
I have promised myself that I am not going to visit that particular glass palace again.
(Oh, and I'm sure no-one will be surprised to learn that despite the 'advisory' last year on bushes being somewhat worn, and the fact that nothing has been done to them since, nothing about bushes this year. This year's advisory was brakes juddering slightly.)
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Alas I had already agreed for the dealer to do the work and it came to . . . £177.03. Ouch.
Personally I don't think that's bad, the bearing is probably around £40-50 plus 2-3 hours labour.
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Personally I don't think that's bad
Thanks. That makes me feel a bit better about it. All encouraging comments welcome!
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2) What factors would cause a wheel bearing to wear out faster?
Incorrect fitting technique.
Putting a load onto the balls/rollers during the fitting process (by, for example, pressing onto the wrong race) will cause damage. And a hammer should never come anywhere near a ball or roller bearing.
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My wife's 1400cc petrol Astra, S Reg, has had two wheel bearings in its 70k lifetime. Both of them were on the same axle. I find this odd and wonder if, when the car was constructed, the body jig was slightly out of true.
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I discovered some time ago, that wheel bearings tend to be case hardened, but if you buy the same bearing 'off the shelf' for general use, they tend to be through hardened.
I've never been able to find out why.
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70k for a wheel bearing is about right, for both to go on the same axle sounds pretty good , did you mean on the same hub?
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i have a question for the spanner lads, is it false economy buying things like wheel bearings from the local motor factor or is it best to get them from main dealer? reason i ask my brother fitted a wheel bearing to his ford and it was manufactured by daewoo?
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have a question for the spanner lads, is it false economy buying things like wheel bearings from the local motor factor or is it best to get them from main dealer? <<
I avoid buying from main dealers, unless car is under warranty, or unless customer insists on it. Generally Its because The "genuine" parts are not made by the vehicle assembler and are often much more expensive (with some notable exceptions; esp headlamps) for the same item.
Wheelbearings are generally a very good example of this. A bearing from a dealer will be exactly the same as from a factor (generally; certainly ford, vauxhall, citroen, peugeot, renault) but will not include all the seals and clips needed (all sold seperatly to increase the price). The kit from a factor will include everything including hub nuts, and the bearing will have the same manufacturer as the dealer 1 , with the same part no stamped in etc.
Knowing a manager from a bearing plant in luton, the bearings come off the same assembly line wherever they are sent to. So there is no qulaity advantage being sent to the dealers etc; just the price difference.
Others will tell you the dealers the best place to go.
I leave the choice to you.
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>>it false economy buying things like wheel bearings from the local motor factor or isit best to get them from main dealer?
It doesn't matter, except on price. You could go to an ordinary bearings stockist, nothing to do with a motor dealer/factor at all. The MF will quite possible be more convenient, & have a better price, though.
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Sorry Zookeeper, I did mean the same hub. The other three bearings are the originals.
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