w124 wheel bearings service

[TomO]

After reading several archives about this, I'm left with the impression that front wheel bearings should be repacked at 90k miles. Are new bearings for the perfectionist or everyone? Second question: what solvent is used to remove old grease if re-using old bearings? I'm doing all 4 rotors at 120k.

[Kestas]

Wheel bearings aren't that difficult to work on.... you just have to follow instructions. Anyone comfortable doing mechanical repairs on a car should be able to do bearings. Being a perfectionist certainly helps. The main thing is to have everything clean and contaminant-free. Replace bearings in complete sets (inner race, outer race, and rollers) if they are less than perfect. Mounting surfaces must be clean and free of particles and burrs for smooth and square engagement. Seals must be replaced at the same time.

I usually use mineral spirits or kerosene to clean bearings, then dry as much as possible. If you don't feel comfortable with that, you can follow up by cleaning any residue with alcohol.

I don't know why 90,000 miles is suggested. I'm still from the old school of regreasing every 30,000 miles. Maybe someone can shed some light on this.

M-B have a special high temperature anti-friction bearing grease that's packaged in the right amount for the two front wheels. The part number used to be 001 989 23 51 10.

M-B wheel bearings generally don't need to be repacked until you replace the rotors (90K?).

Another thing that can be used to clean wheel bearings is diesel fuel but it stinks if you get it on you.

The way to adjust play is with a dial guage unless you are highly experienced with these cars.

[TomO]

Thanks. Where does one get a dial gauge? Buy, rent, or borrow?

[Mike Richards]

Ckeck out what Benzmac had to say in this thread:

Question for M.B.Doc

I believe it applies primarily to front wheel bearings and I'm at a loss for why a reasonably talented person would need a dial gauge to come up with what's suggested in the thread. I say this because too many have done it without a dial gauge.

My 2 cents.

[csnow]

Always replace the seals when re-packing.
Bearings can last for several hundreds of thousands of miles if repacked every 90-100k and resealed to keep them clean.

If there is any question on their condition, replace them. Who wants to do this job again anytime soon?

Diesel fuel works great for soaking the bearings clean.
(I actually use heating oil from my oil tank, which is almost the same minus a few additives)
I use spray brake cleaner to finish up the races,insides of the hub, and spindle.

Getting the right torque on the retainer nut can be tricky.
The right special tools are great for this.
I have done so many at this point, that I now just do it by feel.
You are trying for a balance of no drag, and just the slightest hint of play. Once the wheel is back on, you can see how you did by grasping the tire at 12:00 and 6:00, and rocking it inwards and outwards.

Best of luck