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 E30's 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
The 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 car's 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 Wayne's article on jacking up the BMW E36.
Once 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.
Now, look behind the brake caliper and disconnect the ABS speed sensors on both wheels. Also disconnect the brake wear indicator sensor on the driver's 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.
We 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.
Now, 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.
The 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.
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 ft./lbs.
Next, 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 driver's side.
Have 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. Put 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 to see more technical articles like this one, please continue to support Pelican Parts with all your parts needs. If you like what you see here, then please visit our online BMW catalog and help support the collection and creating of new and informative technical articles like this one. Your continued support directly affects the expansion and existence of this site and technical articles like this one. As always, if you have any questions or comments about this helpful article, please drop us a line.