Jack requests...

Your expert suggestions invited:

This 93 Corolla at 265,000 km makes resonant noise from the left rear wheel.

Any suggestions on how to diagnose the cause?

Thanks for your help, Jack.

Try *lightly* engaging the parking brake (while moving) and see if that
changes anything... you might have dragging brakes....

"Ralph" <nospam (AT) thanks (DOT) com> wrote

Brakes dragging or worn; bad wheel bearing; bad tire; bad wheel cover.
--
Ray O
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Jack ponders:

Thanks for the replies.

It could be a bad tire. I'll try rotating the tire and see if the noise
relocates too. What would make a tire go 'wup-wup-wup'? A broken belt?
These are Wal-Mart specials, and although warranted 100,000 km I anticipate
trouble getting an adjustment if the treadwear looks unusual.

It's probably not the brakes.

How do I check for a wheel bearing?

Regards from Jack.






("We are simple people and easily confused by the slightest complexity. -
Jack Vance)

"Ralph" <nospam (AT) thanks (DOT) com> wrote

The noise you're describing is generally caused by a broken belt.

--
Ray O
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1993 Corola LX at 265 000 km - Left rear wheel


Thanks for your helpful ideas. The stuck wheel came off with a few days'
penetrating oil on the hub and a short trip with loosened wheel nuts.

My questions are, what is the cause of tire cupping, and is the wheel
bearing ok.

The tire is badly cupped - looks like it was shaved with an axe! Would this
be caused by the very old, off-balance brake drum? The drum had big hunks
of metal flaking from the outside. The distribution of missing metal was
uneven. You can chip lose rust off with a hammer. This drum is probably
original and is worn almost to max. specs. (ID 201 mm). The shock is
working properly - I put gas shocks on in 2003. On casual inspection,
various suspension parts nearby don't seem to be missing or damaged.

The wheel spins freely without noise or play. If spun with the tire and rim
on, it keeps rolling for a dozen turns or so. The hub alone (drum removed)
spins freely, but is stopped in a few turns by friction. Is this
acceptable? Should I remove the hub to look at the bearing, and perhaps put
a bit of grease on it for old times sake?

Will a cupped tire wear smoother e.g. through rotation? Or does the cupping
remain forever?

Thanks,

Jack

"Ralph" <nospam (AT) thanks (DOT) com> wrote

Cupping or scalloping refers to a scalloped edge, which can be cause by bad
or worn shocks/struts, improper wheel mounting, loose lug nuts, bad wheel
bearings.

If one outside edge is smoothly worn more than the rest of the tread, then
that is a sign of improper camber.

If one side is feathered, then that is a sign of improper toe.

If both outside edges of the tread are worn, that is a sign of low tire
pressure.

If the inside of the tread is worn more than the outside, that is a sign of
excessive tire pressure.

The wheel on a vehicle with drum brakes should not spin freely. When raised
off the ground, it should spin once or twice and stop if the rear brakes are
properly adjusted. Improperly adjusted rear brakes will cause more rapid
front brake wear and longer stopping distances.

If you are getting a growling noise from the rear, that could be from the
brakes or from the wheel bearing. If you are going to go through the
trouble of removing the wheel bearing, you might as well re-pack it
properly, not just apply grease on the outside. To re-pack it properly, you
should remove all the old grease with a solvent, dry thoroughly (do not spin
the bearings with compressed air!) and re-pack with a good quality
high-temperature wheel bearing grease (not lithium grease). There are
devices to speed up the re-packing process and some even force out the old
grease while replacing it with new grease. If you have a wheel bearing
packer, then the process goes a lot faster.
--
Ray O
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