Each front hub is supported on taper roller bearings while the wheel bolts which are splined are pressed into the hub flange which has a spring loaded lip type seal at the inner end and retained on the stub axle by a special washer slotted nut and split pin. To inspect hub bearings, lift the car until the wheels are off the ground, turn them round round and you will get to know that they are free from noise, also wiggle the wheel to check for the presence of play. If there is evidence of excess play, re lubricate the wheel bearings first; if the roughness is still there then, disassemble to have look at. For adjustment, therefore, you have to remove the road wheel you then take off the grease cap and tighten up the nut to the extent of 1kgm while turning the hub and you then loosen the nut slightly to allow the movement of the special washer. End float generally should be between 0 and 0.03mm but in some countries it is between 0.02 to 0.06mm as measuring by dial gauge. After adjustment, turn back to align the split pin hole and then replaced the split pin with a new one, also cleaned the grease cap and placed 20g of approved grease inside it and tapped it tightly back into place. For removal, it is necessary to slacken the wheel nuts, lift the car and take off the road wheel Removing brake caliper and glued cap, split pin, hub nut, special washer and collecting inner race of outer bearing, grease seal and inner race of inner bearing also have to be made. Servicing consists to clean and remove any debris of the hub, bearings as well as the grease cap, clean it in solvent, the bearing races should also be washed separately. Oil the stub axle and check as to whether there are any damages and smoothen the part if the dents/holes are slight; the outer races of the bearing must also be inspected for signs of wear and if the decisions made are that they are worn they have to be replaced as well. Light oil should then be applied on these inner races before they are pressed back into their outer races; the races should be smooth to touch; they must be clean to avoid dirt complications or problems. To re assemble, position back the outer race, if drilled, apply the authorized grease to lubricate the wheel bearings, stow the hub and fit the new inner bearing with an other new grease seal. Place the hub assembly over the stub axle, pack the outer bearing and then refit it with the special washer and nut and then adjust the wheel bearings as before. Last of all, grease the grease cap and fit it back, replace the brake caliper, press the brake pedal to set the required clearance and replace the road wheel before lowering the car.
Posted by BMWPartsDeal Specialist 
