it's the rear wheel bearing...

[Chisheng Huang <cph@domain.elided>]

I posted the following message last November.   Since this was not my
wife's primary car and my work was quite busy, I didn't start looking
for the real culprit until a few weeks ago.  Suggestions from fellow
Alfa digesters pointed to 3 suspects: rear sway bar, u-joint, and
wheel bearing.  Since everything was tight underneath the car, there
was no abnormal vibration at the gear shift knob, and the noise came
from the rear right wheel (this was confirmed by my riding a bicycle
and chasing the Spider driven slowly by my wife), the rear right wheel
bearing was the prime suspect.  Last Thursday night, while trying to
take out the right axle shaft, I noticed there was dirty grease on the
inner brake pad and the inner brake shoe linings.  At this point, I
was 90% sure it's the bearing.  As I couldn't win the tug-of-war with
my Spider to get the axle shaft out without using a slide hammer
puller, I assembled everything back together last Saturday and drove
her to an Alfa shop.  The mechanic was 100% sure the rear right
bearing was shot upon learning the symptoms and the dirty grease on
brake parts.  With the right Alfa factory tools, he was able to get
the dead bearing out and a new bearing in in a short period of time.
He also thought this was a weird case of rear wheel bearing failure.
The noise was always there while going forward and the free play (from
grabbing and shaking the tire) was much less than that I remembered
when my 33 and Alfetta GTV 2000 had a bad wheel bearing.  

I would like to thank Bryan Bettencourt, Chris Finks, Greg Hermann,
Rich Hirsch, Fred Di Matteo, and Brian Shorey for their valuable
suggestions.

Best wishes,

Chisheng Huang


> My 86 Spider Veloce recently developed some weird noise that I can't
> locate the source.  This noise consists of two parts: a scraping sound 
> followed by a clonking sound.  The clonking part is much louder than
> the scraping part.  The frequency of this scraping, clonking noise is
> related to car speed, not engine speed.  I can not reproduce (or I
> can't hear) the noise by driving my Spider backwards.  The noise seems 
> to come from the rear right wheel.  I already took off the rear right
> wheel, brake caliper, and rotor disc but found nothing loose.
> Everything is tightly secured there.  While poking around with the
> rear right wheel off the car, I rotated the wheel hub in car's forward
> direction many turns with my hands.  Sometimes the rotation would
> suddenly stop and I had to apply greater force to make the wheel hub
> rotate again.  Once it passed that point of big resistance, I could
> again rotate the wheel hub with less force.  I'm not sure if this is
> normal or not.  I also got underneath the car but found nothing loose
> there, either.  I don't know what to do next.  So, here I am, asking
> for help.  I'll be very grateful if you can shed any light on the
> source of the noise.

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