Bearing Change using Hub Grappler
So here is the write up with pics on the left rear bearing using the Hub Grappler on-car bearing/hub extractor. This is on a 2001 ML320. Attempt this at your own risk. I make no guarantees but I basically followed the Mercedes WIS document.
1. Jack up car with jack stands and chock the wheels. Safety first!
2. Remove wheel. Disconnect speed sensor and brake wear indicator bracket.
3. Remove caliper. Suspend securely.
4. Loosen axle nut (36 mm). This is best done with the rotor still on as you apply the parking brake to hold the rotor while you torque the nut off. I didn't reinstall wheel bolts during this step but it would probably be a good idea for more secure holding of rotor to hub instead of just the allen bolt. I used a 3/4" drive 40" long breaker--came off like butter. Alternatively, you could leave the caliper on and have someone step on the brake. I used the parking brake method. On a front bearing job, you can slide a drift pin through the caliper window and into the vanes of the vented rotor.
5. After axle nut is off, remove rotor.
6. Remove parking brake hardware and disconnect parking brake cable. This requires pinching of some tabs on the plastic retainer that holds the cable to the spindle. These are located inside the recess where the cable comes into the spindle. I didn't know this and ended up breaking the tabs by forcing out the plastic retainer from the back side. It still reinstalls snugly without the tabs and I dont' think it will cause a problem. If doing front bearing, this step does not apply.
7. Remove tie rod nut (22 mm) and disconnect tie rod. I used the puller with the Grappler kit (pics 1 & 2). Remove upper control arm nut (19mm) and disconnect upper control arm (pic 3). This came off with several gentle taps with a hammer--no need to pulverize it. Good time to inspect ball joints.
8. Press axle from hub. This required the puller tool (pic 4). Suspend axle safely. This is a good time to clean all debris off the speed sensor notches on the axle.
9. Reinstall upper control arm and nut. This is to hold the spindle steady while extracting/installing hub and bearing.
10. Using the Hub Grappler tool (pics 5-10): Extract hub. The outer race of the bearing will come off with the hub. Use the kit puller to remove the outer race from the hub. Remove C-clip. Extract old bearing. Clean bearing housing of all loose dirt and rust. Press in new bearing. Install C-clip. Press in hub. I used penetrating lubricant liberally on the hub and bearings during every part of the process. I also put the new bearing in the freezer before starting, and the hub in the freezer after removal, to make installation easier.
11. Reassemble everything in reverse order. Careful to align axle teeth with hub teeth. Torque on upper control arm nut is 50 Nm (I just tightened by feel as torquing it would require a crowfoot wrench). Torque on tie rod nut is 55 Nm (this one is easily torqued with standard socket). Used blue loctite on control arm and tie rod nuts, which are plastic-insert lock nuts. Torque on axle nut is 490 Nm (YES 490 Nm!), and this is best done after reassembling parking brake/rotor to keep the hub from spinning (During reassembly, I just tightened axle nut without torquing to seat axle into hub). Good idea to temporarily reinstall wheel lugs to hold rotor to hub when torquing axle nut. For front bearing job, use drift pin in rotor vanes to keep hub from spinning.
12. Install sensors and brake calipers. Clean the speed sensor well. It tends to accumulate gunk and rust. I replaced my pads with ceramics since I had the calipers off.
13. Install wheel. You're done. Shouldn't need alignment if things were aligned prior to procedure.
Took me about 6 hours. That includes taking pictures, and cleaning and inspecting parts in the process.
