Wheel bearing checks specs

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Should warrant checkers have a list of the type of wheel bearings in vehicles?
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.
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What's a "Warrant checker"?
--
"Bother", said Skipweasel as he molished a little jig.



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contains these words:

so I guess read MOT tester
Steve the grease

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Ah, right.
As far as I know they don't have a list of allowable play, they just waggle it and if it waggles too far they fail it.
--
"Bother", said Skipweasel as he molished a little jig.



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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?
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Probably not. Is it whining or droning? If not I wouldn't worry.
--
"Bother", said Skipweasel as he molished a little jig.



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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 km/year.
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Quite likely. We've a town here called Milton Keynes where almost every junction is a roundabout. Front left wheelbearings and tyres and shock absorbers go first.
--
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'Ball' type bearings don't really wear. The tracks are case hardened, and any 'wear' soon results in total failure. I'd guess you're just seeing production tolerances.
--
*Very funny Scotty, now beam down my clothes.

Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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That's interesting.
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 on.
Now I am wondering if anyone will do my stick test with new sealed bearings installed.
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.
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If the housing the bearing is in has any play, you're in trouble, as it will get worse. Of course the play disappears with the brake on - the backplate is rigid.

There is some clearance in all bearings, and this will vary slightly in this non critical application between samples.

More likely that will give trouble than the part it's meant to be protecting.
--
*Red meat is not bad for you. Fuzzy green meat is bad for you.

Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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On Sat, 17 Apr 2004 12:32:35 +0100, Dave Plowman

Nope but you can buy such systems for checking plant. Even the cheapest ones cost a four figure sum though & they all rely on the operator to a large extent.
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If they rely on the operator, you might as well get him just to check the parts they're monitoring - if they are easily accessible like the parts the OP wants monitored on a car.
--
*Someday, we'll look back on this, laugh nervously and change the subject

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On Sat, 17 Apr 2004 19:44:02 +0100, Dave Plowman

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.
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wrote:

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 only slight. Mike.
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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 *

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dot co dot uk> wrote:

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 component completely. 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. Mike.
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[...] In a bearing, the hardened flakes rapidly chew the

Do wheels come off? Is there much noisy warning first?
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On 18 Apr 2004 10:29:30 +1200, Brian Sandle

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.
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dot co dot uk> wrote:

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 stop. :-) Mike.
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