Should warrant checkers have a list of the type of wheel bearings in
I have a Fiat Uno and the rear wheel bearings are sealed ones. They
are secured with a 160 lb ft torque nut which is staked. Does that
affect how much play is safe when there is no noise for the bearing?
I read sealed bearings should have no play, but adjustable ones can
have some. Therefore should the warrant checkers know which are which?
I have been struggling to measure the play which seems to be about
0.25mm or 0.3 mm at the rim. I mean to measure it better, but at the
moment I feel that the wheel with the lesser play was rejected, the
other said to be marginal. But maybe both are unsafe for sealed
bearings? They do not have noise or roughness but without the brake
drum on they do not continue to spin.
Not taking account of whether it is sealed bearing or adjustable?
Now I wonder if I could jack up the wheel and lower it slightly again on to a
long socket extension lying on the floor pointing backwards. Then when I rock
the wheel that would rotate and the driver would act as a pointer for play
measure. I would tape a long pointer stick to the driver to make the movement
easier to measure.
I am hoping to get the subjectivity out of it a bit. Worth it?
Thanks everyone for the help. I went back to see the supervisor and he said the
bearing is not rough at all and gave me the warrant.
Interesting that the left bearing has worn more than the right. We drive on
the left side of the road here, maybe there are more bumps. Or is it that that
side brake was grabbing for a bit? I think it may have been, overheating the
seal. I better keep a watch on it. However that would have been before the
previous warrant, even two back. I do not do much in this car, about 5000
In my answer to distinguishing between bearing play and bush play
before, I meant to mention that I think the bush play would still show
when the brake is on. At least the bearing play disappears with brake
Now I am wondering if anyone will do my stick test with new sealed
I wonder if any cars will have various microphones about various places,
The knock sensor is sort of one. But I am thinking of near exhaust pipe,
each accessible bearing or equipment like water pump, wheel bearings,
cam belt & sprocket, with a sort of voice recognition computer deciding
if things are out of tolerance.
You can spot the problem earlier which gives you time to plan to fix it,
factory downtimes rather more expensive than a hire car:-) & you expect to
change bearings, I wouldn't be suprised if the majority of cars make it to
the scrapyard with the original bearings in them.
Actually they do. I've replaced bearings in machinery, where the only fault
has been excessive play. Otherwise they've run perfectly smoothly.
These are bearings that have not been subjected to any shock.
On a wheel bearing, I would assume that once any significant play develops,
road shock could crack the ball or race surfaces, leading to rapid failure.
With larger bearings that may be true, but IME bearings up to 75mm diameter
at least are hardened right through. Maybe the balls, rollers, and track
surfaces are slightly harder than the rest, but the difference, if any is
I must admit it's ages since I had to change a wheel bearing, but the last
one I did had definitely broken up on the track surfaces - indicating some
form of case hardening. Think it was an Austin 1800 front wheel bearing.
*Parenthetical remarks (however relevant) are (usually) unnecessary *
Dave Plowman email@example.com London SW 12
There's a specific name for that condition. I can't remember what it is.
Dave Baker would probably know, but even through hardened metal can surface
flake, if it is repeatedly hit. Particularly with extremely hard components,
like those in a bearing.
Presumably the impact locally stresses the surface. Enough to cause a thin
layer to crack away from the main component, but not enough to crack the
I'm just guessing. I don't really know why it happens, just that it does..
Once it does happen. In a bearing, the hardened flakes rapidly chew the
bearing surfaces and ball cage until the bearing gives up completely.
Oh yes, they get noisy but they normally seize rather than fall off & once
they start being noisy they can carry on for thousands of miles or (My
last one) become unbearable in a couple of hundred miles.
I've never known wheels to come off.
And yes. You get plenty of warning. It's usually quite progressive. Starts
maybe just as a whine, which can last for quite a long time, gradually
getting worse. The car stays drivable, but long before the bearing packs up
completely, the noise and vibration will convince you that you'd better
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