Re: wheel bearing?

[Alex Kowalski <akowalsk@shrike.depaul.edu>]

Andrew Duane USG/PE wrote:
> 
> Hairy green toads from Mars made Jack Rich say:
> 
> >      When I corner in my 84 4kq to the left, there is a steady
> >      thump-thump-thump sound, whose rapidity is proportional to my speed.
> >      When I go straight or turn right, there is no unusual sound.  This
> >      sounds like a wheel bearing about to go (right?) and it must be on the
> >      right side of the car where the cornering forces are highest (right?),
> >      but I can't tell if it's the front or the rear.  I also am not sure if
> >      a wheel bearing makes a thump once per tire revolution vs. a steady
> >      rumble.
> 
> It's a CV joint, not a wheel bearing.
> 
> I forget which turn makes which side thump.
> 
> --
> 
> Andrew L. Duane (JOT-7)                 duane@zk3.dec.com
> Digital Equipment Corporation           (603)-881-1294
> 110 Spit Brook Road
> M/S ZKO3-3/U14
> Nashua, NH    03062-2698
> 
> Only my cat shares my opinions, and she's too heavy to care.

>From my experience, wheel bearings moan on these cars when they're worn 
out.  You can hear it is a low, rumbling-grinding-type vibration that 
occurs on one side of the car only and gets louder in turns opposite the 
affected side of the car. Unless it is seized, but then I can't imagine 
you going very far on a seized bearing.  The CV joint suggestion is a 
good one.  Turn the wheel full lock at a standstill and then drive in 
that direction.  Maybe with an assistant you can hear from which side of 
the car it is coming.  Also, two other, outside chance things:

1:  The brake shield has been dented or hit by something in the road and 
has been brought sufficiently close to the rotor to intermittently 
contact it when that wheel is loaded.  Of course, this would sound more 
like a glancing grind than a thump.  The kind of runout/rust on the rotor 
that could lead to this sort of sound should tell you to replace the 
rotor and watch the wheel bearing if this is true, because there's play 
somewhere, but it happened to me.  The outermost diameters of the front 
disk rotors on my car were not in contact with the pads, and consequently 
rusted and developed strange protrusions over time, which caused this 
problem when I hit a rock.  BTW, I just bought a set of Brembo vented 
front rotors for my '84 4KQ from Rapid Parts and they are superbly 
manufactured units that I am now using to replace the CrudCo replacement 
rotors that the previous owner slapped onto the car.  

2: Is it a low, damped thump, thump? (more like a bhump, bhump?) (Ok, I'm 
a weirdo).   If so, check the tire again by spinning and eyeing it 
carefully for an egg somewhere along the tread and both sidewalls.   

Best Wishes,

Alex Kowalski,
'84 4KQ