Hello, I'd appreciate any help to eliminate significant front brake rotor run-out and vibration after I replaced the pads and rotors. This is on a 2016 E350 wagon with 110k miles.

The front rotors I removed had about 2/1000" run-out and I could slightly feel it. I had to beat them with a hammer for five minutes to remove each one. The hub faces were significantly rusted. I used a wire wheel on an angle grinder to brush off the rust. Now I can see the circular lines on the face of the hubs but they are significantly pitted and may still have rust protruding. I didn't get a good read of the hub face run-out.

When I installed the rotors before cleaning the hubs, they had 20/1000" run-out. Braking with them felt dangerous. I removed them, cleaned the hubs, and reinstalled. Now they have 4/1000" run-out and braking produces annoying vibration. I might even feel a little vibration while not braking.

I measured the run-out of one new rotor (Zimmermann) on a lathe and it was under 1/1000", so I trust they are good. I lubricated the slide pins and installed new pads (Mercedes brand). I torqued everything to spec according to the WIS document. I can't think what else might be causing this.

What do you think? Must I replace the hubs due to rust damage? What tools could be used to clean them or make them flat? Could a machine shop resurface them? Or did I throw them out of spec from beating them with a hammer? Thanks for your input.


Front hub before cleaning


Front hub after cleaning

 

Does 4 matic front bearing also have play adjustment requirement like RWD model ?
RWD front bearing play is 0.01mm to 0.02mm or 0.393 to 0.787 thousand of an inch.
That can create false run-out too if 0.03mm or more.
UPDATE : 4matic has no bearing play adjustment for front. I just read the WIS.

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That is freakin lots of rust on your bearing hub/flange. I do not eny countries with salt on the road during winter
If I were you, I would replace both L/R hubs which is called the flange, the bearing and the circlip. WIS attached.





Item 50. The flange or hub




Not only safety but for high speed comfort we need them surfaces as flat as possible.
Hub>>>Rotor Disc>>>Rim
Imagine on an adjustable RWD W212, the front bearing play, 0.02mm is maximum or 0.787 thousand of an inch. So all need to be very well mated.

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Mine when I first removed the disc rotor, mine is RWD
Needed puller tool



My hub/flange run-out



After I applied anti seize as rust protection, the rotor disc will drop whenever the small torx screw removed .... so nice.


Above is March 2021.


The next check for rust on hub was 29th Nov 2021, all good.






Yours in 2025 vs mine in 2021. With anti seize hubs in my non salted road stay good.




Rear hub, Feb 2021 first time removed , cleaned and use anti-seize and when in Nov 2025


.



.




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FRONT : The old first rotor






I hate these un-even surface




I replaced the rotors with new ones. MB genuine. Made by Brembo if I remember right.



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Early next year I will check and apply anti seize again on the FRONT hub/flange.


Stay safe when under the car......

 

I was gonna volunteer "loose bearings"... but Surya confirmed 4M runs non-adjustable wheel bearings.


Once you're done dealing with hub and bearings.

Consider next sources of wheel looseness:

• tie rods,
• control arms,
• ball joints,
• SB links,
• ...

all have an expiration date.

 

Thank you for the input, @S-Prihadi and @CaliBenzDriver . To replace the hubs, I will have to bring the steering knuckles to a machine shop to press them out/in. I think the hubs felt a little rough while turning them as if the bearing failed. I believe that diagnosis must be made with the axles disconnected so the hubs can spin feely - if they spin too much or feel rough, then they're bad; if they slow down quickly after spinning or feel smooth, then they're good. Is that right?

This has turned into an expensive break job.

 

Try not to disassemble more than necessary.
Check if there is any freeplay with hubs installed to axles.

 

@S-Prihadi or anyone else, please post the WIS instructions for removing the steering knuckles on a 2016 E350 4Matic wagon. Also any other WIS instructions referenced by it. I like to ensure I have the correct torque values and procedures. Thank you.

@CaliBenzDriver I like the idea of replacing the rusty hubs since their faces may be making an uneven mating surface for the rotors. I will check the hub-axle connections. I also hope to disconnect the hub-axle to feel the hub bearing spin freely, seeing if it is as rough as I thought. I'll probably check those before removing the knuckle and taking them to a machine shop. Thanks again.

 

@FireFox31 if you are going that route, there is a known failure you can already repair.

The 4Matic front passenger axle + bearing both get damaged as the system ages.
Actually it is the Transfer case/differential that are involved in stressing out just one corner terminaly.

Meaning don't only focus on the rusted brake hubs while you are tending to this.

You'll best need to deal (assess/maintain/repair) your transfer case differentials at this time.
They use very little oil without filtration that help glitter shorten bearings life. Check bearings freeplays.


> REPAIR SCOPE... Inspect & service as needed:
-- Xfer case + Differentials

-- AXLES part list may call for one or both sides:
hubs + bearings + axle (+ rotors)


I do not have hands on with this 4Matic.
Besides these axles shafts are famous for rusting mild-steel ABS SENSOR RING that require replacement of ring or shaft.

 

I am not in Jakarta at the moment where my PC is with EPC/WIS.
Me now year end in Bali., only dumb-azz laptop I bring.
Look for TimC300 post, he has a link to an online WIS somewhere, or you can PM him, he is very helpful.
This is him : https://mbworld.org/forums/e-class-w...ml#post9246206

 

Thanks @CaliBenzDriver and @S-Prihadi . This is great information. This is becoming a very VERY expensive brake job. But I want this car to last many years so I will do the preventative maintenance that is required.