Rotor job soon.
 

I'll have to replace the front rotors on my 240d soon. It's been so long since I've had one of them off I forgot what's involved. If I order new rotors do they come with the race or races installed and then I just transfer the old bearings or replace with new to the new rotor?

The brake rotor is fastened to the hub with allen head fasteners that have to be heated to be removed. Use blue locktite on these fasteners during reassembly. Don't worry about the bearing races unless you can see damage. Clean and repack the bearings when you put everything back together.

Bashing em with sledge-hammer to free rotors from hubs was toughest part of operation for me. You will need a vise, block of wood and sledge to free em up. Allens were no prob, inside wheel bearings press-fitted into hub. At 200k+ miles I'd replace the bearings knowing never go back there again. Entire operation of rotors and bearings costs about $110 in parts.

I'm glad I asked. The rotors I've seen in catalogues like Mercedes Shop show the rotor for sale attached to a hub for $37.00. I'd much prefer to skip that step of breaking free a rotor. So, if the rotor and hub are sold as one piece I'll have to assume a new race is already pressed into the hub and I just have to replace or swap the bearings.

The rotor and hub are not sold as once piece. There is no reason you should ever have to buy a new hub unless you hit something. To remove hub from rotor, attach rotor to a wheel with a few lug bolts, then use a breaker bar + allen socket to remove the bolts. I got them off without even heating them using this method. Inspect the bearings, most likely they will be fine. Clean them off super well with brake cleaner etc...then do a good job repacking them with good quality wheel bearing grease. Replace the two seals, and put it back together. Its not all that hard, it just needs to be done carefully and precisely.

You should only need: Rotor, Brake Pads, Wear Sensors, some grease, and the two seals. MAYBE new allen bolts (obtained via dealer, not hardware store) if they are really rusty...your call. Mine were ok.

dont ASSuME that, you'll be wrong. if you get a new hub, get new bearings and races, too(all 4 pairs) and then may as well replace the radio suppression spring and the grease cap( a long bearing kit). but that is some dough, so instead, just get 2 rotors and 2 wheel seals, some disc brake bearing grease and go to town. the shop wiki should have the procedure for setting wheel bearings up.

not too bad a job, a couple hours tops. bolting the jhub to a losse tire is the key, then an impact wrench or long breaker bar. no heat required for me, either. do remember the locktite for reassembly.

It might be better if you assumed that the rotor is not sold with the hub. Otherwise, you are going to be disappointed.

A way to remove the hub from the rotor, using a couple of lug bolts, put it back on the wheel/tire, turn face down, kneel on the tire and using a 10mm ratchet, unbolt. Then use a cold chisel at the seam, it'll come off.

Use a high quality 1/2" breaker bar and high quality allen socket. Make sure you are pulling with everything good and square and then whale away at it. It is not bad but it will take all your strength to break loose and if you don't keep it all square you will slip and round something off and be sorry.

Not complicated but not the easiest thing to do either.

Reinstalling the bearings is not bad but you need to get them right. I just spin the wheel and tighten til it starts to bind up then back off til it spins freely again....just. No play.

Tom W

Thanks for all the great advice. I hope to get to the job soon.