I could not find a decent write up for changing the rear wheel bearing anywhere on the net. Every forum I checked said to have a mechanic do it. Well here is how I did it. The following goes against almost everything I read on the web about changing wheel bearings. Please use at your own risk.
What you will need:
Air compressor and impact gun with 30mm socket
Slide Hammer kit (I rented this from the local Murray’s Auto)
Snap ring pliers
Hex sockets and assorted other hand tools
3lb Hammer
Piece of wood to hammer against
PB Blaster and WD40
Spray everything with PB Blaster!
Place your new bearings in the freezer. Jack up the car as high as you can get. Make sure the car is securely on the jack stands. This is the most important part as you will be hitting parts of the car with a large hammer. The last thing we need is to lose a BMW enthusiast because his/her car fell on them.
Remove the rear wheels. Put your car in gear and pull the e-brake as tight as you can get it. Now use a 30mm socket and an impact gun to remove the large hub bolt on each side. Disengage the e-brake.
Remove the two dust caps covering the bolts for the caliper. Remove the bolts holding the caliper to the caliper mounting bracket. These bolts are a hex head. (I think they were 7mm.) Slide the caliper and brake pads away from the rotor and use a wire to hang the caliper from the coil spring. Remove the two bolts holding the caliper bracket to the trailing arm and remove the caliper bracket. (I think they were 17mm.) There is a hex head bolt holding the rotor to the hub remove this and remove the rotor. I had to hit my rotors with a hammer a few times to get them off. Repeat for the other side of the car.
Jack up the trailing arm under the hub. This will align the drive axle and make it easier to get to the bolts holding the axle to the diff. Make sure you do not lift the rear of the car off of the jack stands. Climb under the car with a hex socket and a 3” extension. (I think it was an 8mm hex.) Remove the six hex bolts holding the axle to the differential. Make sure the hex socket is fully seated in the bolt. Because of the rubber boot at the end of the axle you may need to turn the wheels to get a good line on the bolt. IF THE SOCKET IS NOT FULLY SEATED IN THE BOLT YOU WILL STRIP THE BOLT. If you are working on the driver’s side you will need to remove the exhaust to get the axle out.
Replace the hub nut on the axle, but do not tighten it all the way. You are going to use the nut to take the brunt of the force so you do not damage the axle shaft. Use a 6” * ½” extension and a 3lb hammer to bang the axle out of the hub. Once the hub nut hits the hub you will have to remove it. Use just the extension and carefully pound the axle the rest of the way out.
Now the real fun begins…
To remove the hub from the trailing arm and bearing I used the same 30mm socket and 6” extension. Place the 6” extension into the socket in the opposite way you would. The extension should be sticking out the bottom of the socket. This will give you enough clearance to pound on the socket but not hit the strut or coil spring. Now place the socket in the back of the hub and pound the hub out of the bearing. It may take a good about of force to do this. The hub will probably come out with the inner race of the bearing still attached. Do no worry about it.
Now you can see the bearing in the trailing arm. There is a snap ring holding the bearing in place. Remove this snap ring. I had to go to Sears to get a big enough snap ring tool.
Place the shaft from the slide hammer through the hole in the bearing and attach the black disk to the end of the slide hammer. Hammer the bearing out. (This is a lot harder then it sounds. It took me a while to get the bearing out) If you are lucky then the bearing will come out whole. This happened on one side. The other side I was not so lucky.
What to do if the outer race of the bearing is stuck in the trailing arm:
I ended up using my Dremel and a lot of cutting disks to cut the bottom center of the race out of the trailing arm. I then used a hammer and chisel to pound what was left out. When you do this you are going to need to clean up any cuts you made in the trailing arm from cutting through. I used the Dremel for this also.
Make sure to use some fine sandpaper to clean up the trailing arm and hub to make installing the new bearing easier.
Remember the part of the bearing still on the hub? Dremel that little guy off also. Now I was told by someone much smarter then myself that you do not want to screw up the hub by going to far and cutting into the metal on the hub. (This is already the wrong way to do this entire job but if you want to get the bearing race off without damaging the hub cut into it with the Dremel until you are almost through the race. Next hit the spot you just cut with a chisel and the 3lb hammer. If you have cut enough away the rest of the metal should crack along the cut and you can slide it off the hub.)
Installation…
Place your hubs in the freezer. Spray the trailing arm with WD40. Take your new bearing out of the freezer. Push the new bearing into the trailing arm as far as you can with your hand. Make sure it is lined up correctly. Using the outer race from the old bearing and the big heavy hammer part from the slide hammer tap the bearing into the trailing arm a little ways. Now place a piece of wood over the bearing and pound it in using the 3lb hammer. (Yes I know every other guide tells you not to pound the bearing in. I do not care.) The bearing will slide almost all the way in. Now use the outer race from the old bearing and the hammer to pound the bearing the rest of the way home. Move the hammer around the outside of the race so you are not always pounding in the same spot. Also make sure the outer race is lined up with the outer race of the new bearing. You do not want to pound on the part of the bearing that spins. Re-install the snap ring. DO NOT FORGET THIS PART.
Take your hub out of the freezer. Slide it into the bearing as far as it will go. Gently tap the hub in a little further. DO NOT HIT IT HARD. Slide the black bolt from the slide hammer kit through the hub bolt and then through the hub and bearing. Place the black disk from the slide hammer on the other end. I used a pair of vise grips on the disk to hold it in place while I tightened the bolt. This will draw the hub into the bearing and is the least likely to damage the bearing. I am sure there is a better way to do this then the vise grips and the black disk but I was too tired to figure it out.
Re-install the axles, brakes, and tires.
What you will need:
Air compressor and impact gun with 30mm socket
Slide Hammer kit (I rented this from the local Murray’s Auto)
Snap ring pliers
Hex sockets and assorted other hand tools
3lb Hammer
Piece of wood to hammer against
PB Blaster and WD40
Spray everything with PB Blaster!
Place your new bearings in the freezer. Jack up the car as high as you can get. Make sure the car is securely on the jack stands. This is the most important part as you will be hitting parts of the car with a large hammer. The last thing we need is to lose a BMW enthusiast because his/her car fell on them.
Remove the rear wheels. Put your car in gear and pull the e-brake as tight as you can get it. Now use a 30mm socket and an impact gun to remove the large hub bolt on each side. Disengage the e-brake.
Remove the two dust caps covering the bolts for the caliper. Remove the bolts holding the caliper to the caliper mounting bracket. These bolts are a hex head. (I think they were 7mm.) Slide the caliper and brake pads away from the rotor and use a wire to hang the caliper from the coil spring. Remove the two bolts holding the caliper bracket to the trailing arm and remove the caliper bracket. (I think they were 17mm.) There is a hex head bolt holding the rotor to the hub remove this and remove the rotor. I had to hit my rotors with a hammer a few times to get them off. Repeat for the other side of the car.
Jack up the trailing arm under the hub. This will align the drive axle and make it easier to get to the bolts holding the axle to the diff. Make sure you do not lift the rear of the car off of the jack stands. Climb under the car with a hex socket and a 3” extension. (I think it was an 8mm hex.) Remove the six hex bolts holding the axle to the differential. Make sure the hex socket is fully seated in the bolt. Because of the rubber boot at the end of the axle you may need to turn the wheels to get a good line on the bolt. IF THE SOCKET IS NOT FULLY SEATED IN THE BOLT YOU WILL STRIP THE BOLT. If you are working on the driver’s side you will need to remove the exhaust to get the axle out.
Replace the hub nut on the axle, but do not tighten it all the way. You are going to use the nut to take the brunt of the force so you do not damage the axle shaft. Use a 6” * ½” extension and a 3lb hammer to bang the axle out of the hub. Once the hub nut hits the hub you will have to remove it. Use just the extension and carefully pound the axle the rest of the way out.
Now the real fun begins…
To remove the hub from the trailing arm and bearing I used the same 30mm socket and 6” extension. Place the 6” extension into the socket in the opposite way you would. The extension should be sticking out the bottom of the socket. This will give you enough clearance to pound on the socket but not hit the strut or coil spring. Now place the socket in the back of the hub and pound the hub out of the bearing. It may take a good about of force to do this. The hub will probably come out with the inner race of the bearing still attached. Do no worry about it.
Now you can see the bearing in the trailing arm. There is a snap ring holding the bearing in place. Remove this snap ring. I had to go to Sears to get a big enough snap ring tool.
Place the shaft from the slide hammer through the hole in the bearing and attach the black disk to the end of the slide hammer. Hammer the bearing out. (This is a lot harder then it sounds. It took me a while to get the bearing out) If you are lucky then the bearing will come out whole. This happened on one side. The other side I was not so lucky.
What to do if the outer race of the bearing is stuck in the trailing arm:
I ended up using my Dremel and a lot of cutting disks to cut the bottom center of the race out of the trailing arm. I then used a hammer and chisel to pound what was left out. When you do this you are going to need to clean up any cuts you made in the trailing arm from cutting through. I used the Dremel for this also.
Make sure to use some fine sandpaper to clean up the trailing arm and hub to make installing the new bearing easier.
Remember the part of the bearing still on the hub? Dremel that little guy off also. Now I was told by someone much smarter then myself that you do not want to screw up the hub by going to far and cutting into the metal on the hub. (This is already the wrong way to do this entire job but if you want to get the bearing race off without damaging the hub cut into it with the Dremel until you are almost through the race. Next hit the spot you just cut with a chisel and the 3lb hammer. If you have cut enough away the rest of the metal should crack along the cut and you can slide it off the hub.)
Installation…
Place your hubs in the freezer. Spray the trailing arm with WD40. Take your new bearing out of the freezer. Push the new bearing into the trailing arm as far as you can with your hand. Make sure it is lined up correctly. Using the outer race from the old bearing and the big heavy hammer part from the slide hammer tap the bearing into the trailing arm a little ways. Now place a piece of wood over the bearing and pound it in using the 3lb hammer. (Yes I know every other guide tells you not to pound the bearing in. I do not care.) The bearing will slide almost all the way in. Now use the outer race from the old bearing and the hammer to pound the bearing the rest of the way home. Move the hammer around the outside of the race so you are not always pounding in the same spot. Also make sure the outer race is lined up with the outer race of the new bearing. You do not want to pound on the part of the bearing that spins. Re-install the snap ring. DO NOT FORGET THIS PART.
Take your hub out of the freezer. Slide it into the bearing as far as it will go. Gently tap the hub in a little further. DO NOT HIT IT HARD. Slide the black bolt from the slide hammer kit through the hub bolt and then through the hub and bearing. Place the black disk from the slide hammer on the other end. I used a pair of vise grips on the disk to hold it in place while I tightened the bolt. This will draw the hub into the bearing and is the least likely to damage the bearing. I am sure there is a better way to do this then the vise grips and the black disk but I was too tired to figure it out.
Re-install the axles, brakes, and tires.
