Re: humming front end (long...)

["John Y. Hung" <jhung@xxxxxxxxxxxxxx>]

To the "humming front end" thread:

A few years ago, I had the same problem on my '84 325e, and had the 
left front hub/bearing replaced by a shop.  At the time, I was scared 
off by the Bentley manual's advice that special tools are needed, so 
the shop cost seemed reasonable.  On my car, the bearings are usually 
sold as part of the hub that is designed for ABS brakes.  So, the 
entire hub/bearing assembly is replaced.  I've heard that it is 
possible to keep the hub and press in/out new bearings, but I don't 
think that is worth the trouble.

I recently replaced the right front bearing myself, with helpful 
encouragement of list members, but no special tools other than a big 
socket ($12 from Sears, I think).  First, remove the big nut on the 
spindle and move aside everything associated with the disk brake, 
including the disk, caliper and sheet metal shield (splash?)  behind 
the hub.  Bolt the wheel back onto the hub.  Using the tire for 
leverage, pull and yank until the hub comes off; the outer bearing 
and races will come off as well.  In my case the inside inner race 
stayed on the spindle.  A small bearing puller can be used to pull it 
off, but I couldn't find a cheap one and be guaranteed that it would 
fit.  So, I took a lunch break to think.

After lunch, I soaked a heavy rag in a bucket of ice and water, and 
then laid the icy wet mass on the spindle for several minutes.  With 
a propane torch, I vigorously heated the stuck race for about 30 
seconds, keeping the wet icy rag on the spindle (I may have bolted 
the splash guard back on before heating the race, but I can't 
remember).  Because the spindle stayed cool, the hot race expanded 
enough that I could slip it off the spindle with slip joint pliers. 
(Work very quickly with the pliers, because the race will cool and 
shrink as it slides over the cold spindle.)  With inside race 
removed, I discovered a thin corrosion film, so I polished the 
spindle with a greasy rag.  To be truthful, I was surprised how well 
the wet icy rag kept the spindle cool (I had concerns about damaging 
the spindle with excessive heat).

The new hub/bearing assembly is easily started onto the spindle. 
Using the big socket as a drift, I tapped on the inner bearing races 
until the old spindle nut could be threaded on.  Do NOT put pressure 
on the hub!  The hub/bearing assembly is easily pressed home with the 
spindle nut, which is then removed and replaced with a new locking 
nut.

I cleaned up the ball bearings, plastic keepers, and inner races to 
keep as coffee table souvenirs.  The inside race has two scar-like 
pits on it.  When mounted on the spindle, the pits faced downward, 
toward the road.  "Humming" is an understatement - the car howled.

It's nice to have a quiet, smooth-running car again.

Hope your hummin' Bimmers get fixed soon,

Sincerely,

John Y. Hung
Auburn, AL

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