From: Jim Steck <[email protected]>
Date: 28 Feb 96 23:58:01 EST
Subject: rear axle bearing noise
>I've been following the wheel bearing thread. My '84 Spider has a sort of
>roaring rumble in the drive train whenever I let off the gas. I don't notice
>that turning one way or the other changes the noise. The noise stops when
>I accelerate or hold a steady speed with a little throttle.
>Is this likely to be wheel bearings, rear axle, or something else?
You didn't mention any vibration, so I will assume there are no unusual
vibrations . . . which may indicate a failed universal joint . . . Wheel
bearings don't usually react to throttle like you described.
This one sounds like the pinion bearings to me. First thing to check is the
drive flange on the front of differential . . . grab hold of it and try to move
it up and down (you could also give the u-joints a yank, just to be sure). If
it moves at ALL, remove the four bolts that attach the universal and check the
nut that holds the flange to the pinion shaft.
If it's tight, the bearings have failed . . .
If it's loose tighten it, reinstall the universal and test.
If the noise is gone, the diagnosis was correct . . . and you've made a
temporary repair. Unfortunately, the bearings will have damage, and need
replaced soon. Continued driving with loose pinion bearings will eventually
damage the pinion and ring gears.
The bearing replacement and adjustment is not difficult, but requires a very
specialized set of gauges.
- -Jim
AutoComponenti
Brookville, OH
-----------------------------------------------------------
From: [email protected]
Date: Mon, 26 Feb 1996 17:28:08 -0500
Subject: noisy wheel bearings
Chris Oates was on the right track as far as noisy rear wheel bearings go,
however his mistake was in the diagnostics. If you're turning to the left and
the noise gets louder and more steady it's the right bearing that's going
bad. The weight transfer is to the right on a left turn and vice versa for
the opposite side. With increased pressure, the bearing noise will become
amplified. If you wait until it sounds as though a DC-10 is landing in your
back seat, it's definately time to visit your mechanic. To replace these
bearings you'll need a special Alfa removal tool. It's possible some folks
have done it in their own garage, but it could get ugly if the bearing is
really tough.
Susie ([email protected])
Alfa Import Center, N.Y.
------------------------------------------------------------