Stuart:
I know I am going to get jumped all over again on this one too,
but here it goes: Perhaps I should use the word allegedly to
satisfy the lawyer types or the product liability bunch.
The term "packing the wheel bearings" is usually used when the
bearing has been removed and completely cleaned of all grease.
Hence the bearing must be completely filled, i.e. packed, with
grease. This doesn't mean smearing grease around the outside
edges of the rollers or balls, but forcing the grease into the
bearing to completely surround the bearings and their retainers.
The manual method is to place grease onto the the palm of one
hand and scrape only one side of the outer race over the grease
many times until the grease is forced, pushed, and squeezed out
the other side of the bearing. This can also be done using a
grease injector needle which looks like a syringe needle with a
grease nipple on one end attached to a grease gun if you know
what a packed bearing is supposed to be. There are also
mechanical devices on the market to do this without the mess.
According to the shop manual on my pickup, the grease inside the
cap should only be around the outside edges. If one can visualize
a cross section of this area looking from the front of the car,
the grease lies more or less in a straight line from the bearing
edge of outer race of the inner roller through the open hub of
the drum to bearing edge of the outside race of the outer roller,
to the outside rim of the cap. I usually put in a little more
than this to fill the area where the grease could be flung by the
centrifugal force of the rotating wheel, and thus the bearings
are always be partially 'submerged' in grease. The attached file
shows this, but I don't know if it will pass through the email
server. So, I am also sending this directly to you.
The vent hole in the cap should be open. It serves two purpose.
If one should get too much grease into the bearing area and the
cap pressed on, the grease can flow out the vent and not past the
inner seal where it could get onto the brake shoes. Also it acts
as a breather for air to get into and out of the hub as the
bearings heat and cool. This again prevents grease from being
forced past the seal or pushing the cap off.
As long as you had the drum off, the proper procedure should have
been to clean and pack the bearings unless this had been done
quite recently. That's what a good mechanic would have done if he
wasn't under the constraints of a shop to 'turn out the work'.
This would also be the normal procedure recommended by most
vehicle manufactures. The wheel bearing seal also is normally
replaced whenever the drum is removed unless it is known to be
quite new and definitely never suffered any damage during the
drum removal.
Blake
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