Are you starting
to hear a grinding, wobbling noise coming from your front wheels? Have you
noticed a wheel that shakes when you drive? Chances are the wheel bearings
may be starting to fail. With most of the E30ís now reaching well over
250,000 miles or more, the wheel bearings may be starting to show their
age. In this tech article, I will go over the steps involved with removing
the old wheel bearings and installing the new units. It is a relatively
easy procedure and should be able to be performed in a few hours. This
article applies to all BMW E30 3 Series models from 1984-91. In this
article, we will be using my 325is as the vehicle in question
first step is to chock the rear wheels to keep them form rolling, then
loosen the front lug bolts (but do not remove) and jack the front of the
car up. You should make sure to jack the car up on a frame rail or other
re-enforced part of the carís chassis to prevent the jack from damaging
the body or worse. (I have seen cars that have holes through the
floorboards from jacking the wrong way) A good reference is Wayneís
article on jacking up the BMW E36.
the car has been jacked up and is firmly supported on jack stands, remove
the lug bolts and pull the front wheels off. You will now see a dust cap
in the center of the rotor. Pry these both off. You will now see a large
nut inside with a pin driven inside the axle shaft. Use a flat-head
screwdriver to pry this pin back and out of the axle shaft. Now have a
helper apply the brakes and loosen the nut. It may be helpful to use an
impact wrench to get this nut off, as it is torques down to 210 ft./lbs.
do not remove the nut at this time. We just need to get them loose.
look behind the brake caliper and disconnect the ABS speed sensors on both
wheels. Also disconnect the brake wear indicator sensor on the driverís
side wheel. Now look at the back of the brake calipers. You will see two
bolts that hold the calipers to the mounting bracket. Remove these bolts
and pull the calipers off. Now you will be able to pull the brake calipers
off the mounting bracket. Use
a zip-tie or wire to suspend the brake caliper. Do not let the caliper
hang by the brake lines, you may rip the lines. Now, remove the two 19mm
bolts that hold the caliper mounting bracket to the hub, and remove the
caliper mounting brackets.
now must remove the brake rotors. This is done by first removing the small
Allen head set screw in the front of the rotor. You may find it helpful to
spray these bolts with a good penetrant spray like WD-40 and let them sit
overnight. This will prevent the screws from stripping or seizing. Remove
the screws and pull the rotors off the hubs.
we need to use a puller to remove the wheel hub from the car. Thread the
puller onto the hub using the holes for the lug bolts and center the
puller on the axle shaft. Now remove the hub. It may take a while to
remove this, so use plenty of WD-40 and keep pulling. Once off, remove the
dust shield form the old hub, and transfer it onto the new hub.
wheel bearings on the E30 are an integral part of the hub, so the whole
hub assembly must be replaced. The new hubs will come with the bearings
already pre-installed. Take the new bearing/hub ad place it on the axle
shaft. Use the puller to push it onto the axle shaft. Keep in mind to
apply force only to the inner bearing race as you could damage the
bearing. Drive the bearings as far as they will go onto the shaft. Now
re-install the retaining nut, but do not tighten it right now.
re-install the brake rotors, and use a new set screw to hold it in place.
The old set screws are designed for one use only and can snap or break if
you try to re-use them. Put the new set screws in and torque them to 12
fit the brake caliper mounting brackets over the rotor and bolt them back
on to the hub. Torque the bolts to 81 ft./lbs. Now cut the zip-ties
holding the rotors and place the brake pads into the calipers. Place the
calipers back onto the mounting bracket and re-install the 14mm bolts that
hold them to the mounting bracket. Re-connect the ABS speed sensors and
the brake wear indicator on the driverís side.
an assistant apply the brakes and torque the axle-retaining nut to 210
ft./lbs. You may find it helpful to use an impact wrench to get it on
there. Once torqued, use a screwdriver to bend the tang into the axle
shaft. This will keep the nuts from coming off. Now put a little bit of
grease inside the dust cap and put them back on.
the wheels back on and install the lug bolts (but do not tighten) now
lower the car and tighten the lug bolts in a criss-cross pattern.
Well, there you have it - it's
really not too difficult at all. If you would like
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