In this final article on wheel bearing replacement, we will focus on the steps involved in changing the rear wheel bearings on the 1984-91 BMW E30 3 Series. Are you starting to hear a grinding, wobbling noise coming from your rear 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 E36’s now reaching over 150,000 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.
To replace the rear bearings, we will need to remove the drive axles from the car. To begin, we will need to first pry the center caps off the rear wheels while it is still on the ground. Now look inside, you should see the drive axle retaining nut. We will need to loosen this nut with the car on the ground. This will help you gain enough leverage to get it off, as it is torqued in excess of 150 ft/lbs. In many cases, it may be easier to simply use an impact wrench. Get the nut loose but do not remove it. Be sure to use plenty of penetrant spray such as WD-40 while loosening the nut. This will prevent stripping or seizing.
Once the car is firmly secured on jack stands, the next step is to remove the lug bolts on the rear wheels and take the wheels off. Now, look at where the drive axles are bolted onto the differential. There are six Torx head bolts that hold each axle to the differential. Before you remove them, it’s a really good idea to clean them off to get any dirt of grease out of the bolt heads. Any good brake cleaner should work perfectly. We don’t have to get them spotless, however just enough to where we won’t have the Allen key from popping out. It’s also a good idea to hit the bolts with WD-40 or good penetrating oil. Typically, I like to let the spray sit overnight, to let the oil work itself into the threads. This will make it much easier to remove the bolts, not to mention preventing stripping and seizing when you hit them with the wrench. Now remove all the bolts. The drive axles will now be free of the differential. Use a piece of rope or stiff wire to hang the drive axles to the car and keep them from crashing downward.
Now remove the axle retaining nut on the outside of the wheels and remove the lock plate underneath. Now, to get the axles out of the car, we will need to use a puller to push them out of the trailing arm hubs. Use the lug bolts to secure the puller to the hub and then tighten the center bolt to push the drive axle out. Now remove the drive axles from the car.
Now, look behind the brake caliper and disconnect the ABS speed sensors on both wheels. Also disconnect the brake wear indicator sensor on the passenger’s side wheel. Now look at the back of the brake calipers. You will see two rubber grommets with a plastic plug installed in them. Pry out these plastic plugs. Directly beneath them, you will see a 7mm Allen head bolt. Use a 7mm Allen head key to loosen then remove both bolts on each wheel. Look on the front of the caliper and pry off the brake retaining clips using a flat-head screwdriver. 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 remove the bearing retainer circlip. Use a pair of circlip pliers to get this out. Now, using an impact style puller, pop the bearing assembly out of the trailing arm. Once out, look on the inside of the bearing housing and clean it thoroughly. This will help you when you install the new bearing assembly. It’s also a good idea to clean off all brake components, nuts bolts, and other mounting hardware.
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 Allen head bolts that hold them in place and tighten the bolts down. Re-install the plastic plugs over the bolts on the rear of the caliper. Now re-install the caliper retaining clip on the front of the calipers. Re-connect the ABS pulse sensors and the brake wear indicator on the driver’s side.
Take the axles back to the car and crawl underneath. Now coat the spines of the drive axles with oil and slide the drive flange back into the trailing arm hub. It may take some effort to get the axle in there, but just keep at it, and it will slide in. Install a new lock plate on the other side of the hub, and thread the drive axle retaining nut back on, but do not tighten it just yet.
Now position the inner CV joints in place and stick a screwdriver through one of the threaded holes. This will keep the joint in place while we thread the bolts in. But before we thread in the bolts, clean them. When I say clean I mean remove all grease and grime. The more clean the bolts are, the less chance there is of them loosening up over time. Once clean, put a dab of loc-tite on the threads and thread them in. Don’t forget to remove the screwdriver as well. Now torque the bolts to 47 ft./lbs. If they are M8 size or torque them 74 ft./lbs if they are M10 size.
Now put the wheels back on the car and re-install the lug bolts but do not tighten just yet. Just get them snugged up. Now jack the car up again, and remove the jack stands from under the car. Now lower the car, and once on the ground, tightens the lug bolts.
The last step is to tighten the drive axle retaining nuts. We have to do this on the ground, as the amount of torque we put on this nut is enough to possibly knock the car off the jack stands. You may even have to use an impact wrench to get it tight. Torque this nut to 184 ft./lbs. (221 ft./lbs. on M3 models) now put the center caps back on.
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Harry M Gousha III adds that one should make sure the parking brake is not engaged, as it makes the job much easier.