OT:Taxis, car rentals and wheel bearings

[Jethro_uk]

Just remembered an oddity I noticed a few weeks ago. Had to get a taxi, and noticed quite quickly a wheel bearing was starting to go. SWMBO commented too and then reminded me that twice the previous year we had a taxi (different each time) and in each one the wheel bearing was going. And a car rental we had in Iceland also had a wheel bearing going.

It's not a component I would readily associated with driving abuse (like brake pads, or suspension items). So I'm vaguely curious as to why it seemed prevalent on heavy *use* (not necessarily mileage) cars ?

[Tim+]

Did you actually check the mileage though? Appearances can be deceptive. High mileage seems the likeliest cause.

Tim

[Davey]

I had one taxi in Portugal a few years ago, an ancient Merc., and I could hear rear axle whine. I looked at the odometer, and it was showing over 890,000 kms. Fair enough, I thought, it's done well. Of course, it could have rolled over and been on its second tour...

[The Natural Philosopher]

kerbings, tight turns. All those put load on bearings and tend to damage them as well, or the covers over the CV joints, letting in water to get at the bearings.

How did you know it was bearings though? worn or damaged brakes squeal ...

[Jock]

Very characteristic hum etc when you apply the brakes with a front wheel bearing failure.

Failed bearings don?t squeal.

[Jethro_uk]

Well the rental was c. 30,000miles.

Can't speak for the taxis with any authority, but they were all less than

3 years old.

[Jethro_uk]

When I ordered a wheel bearing for a Mercedes, years ago, the guy in the parts factor was surprised and said they usually lasted *at least*

250,000 miles.

[Jethro_uk]

The drone which alters slightly as you corner.

Wheel bearings noise is ultrasonic in normal usage, and slowly gets lower and lower as the wear increases.

It's because it comes on very slowly owners don't notice it.

[Dave Plowman (News)]

Modern cars all tend to have sealed pre-loaded units as wheel bearings. Which do seem to fail regularly. Older cars with adjustable taper bearings often lasted the life of the vehicle. But end float and disc brakes aren't the best combination.

[Davey]

How far had the one you were replacing gone? >250,000 miles?

[Jethro_uk]

No, c. 80,000 IIRC - not *entirely* sure it was wearing. But there was a subtle noise, and swapping tyres didn't cure it ...

[Jethro_uk]

and have since the 70s ...

About 3 years :)

bzzzzz ...

[Dave Plowman (News)]

Not all. Mine is mid '80s with adjustable taper bearings.

Bollocks. I've personally never replaced adjustable taper bearings. But many of the unit construction types. Taper bearings are easy to grease once in a while.

[Brian Gaff]

Crap wheel bearings that never get much attention from the greasing department. You do not say which one it was. The other issue seems to be knocking noises from somewhere either in the steering or universal joints in front wheel drive cars. Brian

[Jethro_uk]

I (naively) assumed all wheel bearings were sealed units these days.

Maybe not ?

[The Natural Philosopher]

Pretty sure they are these days.

Haven't noticed one on a regular service sheet for years.

[Tim+]

Brian is somewhat behind the times.

Tim

[Dave Plowman (News)]

They are mostly sealed units these days. One of my points.

[Dave Plowman (News)]

Yes. And although they may give a better performance when new, I'm not convinced they last as well as older methods. And they are generally more of a pain to change.