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Hello,
My 2004 E320 4matic has been giving me issues around braking noise and hard vibration when braking for some time now. I've changed the rotors and pads multiple times and the issue still persists.
I finally decided to get the calipers rebuilt, bought new brake pads, rotors and was thinking this will solve all my issues as the calipers were the only thing that hasn't changed.
As i installed the caliper, I noticed that when i rotate the where one full turn it would get stuck and hard to turn. After taking everything off again and thinking it must've been the rotors not seated on properly, I noticed the when I turn the wheel (while the caliper housing is on) at some point the rotor seems to get closer to the outside edge of the housing (image is attached) almost like the wheel is bent. and this happens on both sides.
After installing everything and taking the car out for a test drive, the vibration is gone, but there is a LOUD grinding (metal against metal) sound each time the wheel makes one full turn and it gets louder when I drive faster.
Can anyone help me with what else could be causing this? I was thinking hub assembly but I am out of ideas. Any input is greatly appreciated.
I had a similar issue on an AMG W210. Unbeknownst to me, the front end had been damaged. This may or may not have made it a challange to properly seat the hub and caliper. The big dust cover was also a bit mangled which, after a bit of unmangling, made it possible to set the system up correctly.
You're not clear if the noise and turning developed on it's own, or after you worked on the car. On the other hand the correct seating may just be a 4matic issue.
Thanks for the response Overheated.
So are you suggesting the hub can be the problem because of a potential damage?
Because this is an issue that I've discovered, I would say this has developed a few years back because I've had an ongoing issue with the vibration that I originally thought was the rotors or caliper. therefore I've replaced the rotors 3 times (with pads) - and any mechanic I've taken the car to had always said it's rotors or calipers, even after checking underneath the car. The issue has been more profound in the past year. Extreme vibration when I hit the brake, where the car shakes.
A few months back I decided to take the wheels off and check on the rotors and notices the same rotation issue that i've discovered and thought it was a warped rotor.
After getting the caliper rebuilt/ putting on a new rotor and pads, I noticed that when i turn the wheel (one full turn) that it became very difficult after one revolution, now, I realize it's not the rotor, caliper or pads. When I try and drive it, it seems like metal grinding and very loud sound after each revolution. Can't really drive it without some noise cancellation headphones.
Again, I don't know jack about 4matic, but yes, check the hub, make sure the bearings, races and seal are in good shape, and that the hub and discs are seated correctly. I Check also that the moving parts don't rub the dust cover and that everything is installed correctly. I recall a similar situation where the caliper was too close to the rotor to be functional, results of the caliper bracket being installed incorrectly. I don't know how, it's a mystery. My 2 cents.
A dial indicator will tell you what isn't rotating in a flat plane. Mount the rotor in all 5 possible positions, measuring the runout of each position. If it changes, the rotor is to blame. If there is one position that brings the runout to zero, use it.. If the rotor runout doesn't change no matter the position, look at the hub and measure the runout on the face of the hub. Oh, and make absolutely sure the hub face and the rotor face that meets it are clean.
Is there still an issue even with the caliper assembly dismounted from the rotor?
Is there still an issue with the rotor dismounted from the hub?
Keep working backwards until the grinding stops.
Last edited by rapidoxidation; Apr 26, 2021 at 01:11 AM.
Great recommendation Rapidoxidation! I will get my hands on a dial indicator and measure the runout of each position.
I am planning on starting from scratch and going to the bare hub and ensuring I am not missing anything.
It's pretty frustrating, considering I thought I solved the problem, but I am sure I'll get there. let me you if there's anything else worth testing. Cheers
Thanks Cetialpha5 for the response.
Yes, I cleaned off all the rust on the hub and will be aiming to work on it again and take it back to the hub to ensure i haven't missed anything.
So the wheel bearings can cause the shift of the hub to move almost 1/4 of a centimeter to the right and left almost touching the caliper housing?
Thanks Cetialpha5 for the response.
Yes, I cleaned off all the rust on the hub and will be aiming to work on it again and take it back to the hub to ensure i haven't missed anything.
So the wheel bearings can cause the shift of the hub to move almost 1/4 of a centimeter to the right and left almost touching the caliper housing?
Check that the races and grease seal are correctly installed and not damaged.
Thanks Cetialpha5 for the response.
Yes, I cleaned off all the rust on the hub and will be aiming to work on it again and take it back to the hub to ensure i haven't missed anything.
So the wheel bearings can cause the shift of the hub to move almost 1/4 of a centimeter to the right and left almost touching the caliper housing?
There's something wrong if you're doing it correctly. I've gotten a set of pads and rotors from FCPeuro which has a lifetime warranty on everything they sell so if mine go, I'll just get another set for free, just have to pay shipping. They've been fine and from what you say you're doing, you shouldn't have any problems. I'm just trying to think of suspension components that might cause your problem. I'm not sure common wear items like ball joints, tie rods etc would cause it, but wheel bearings do go once in a while so it's possible. You should just get it all check out. Something is basically out of spec.
If you spin the rotor and see the distance between the caliper bracket and rotor face change... then you don't need a dial indicator to tell you something it off. 0.002" runout is considered acceptable and you won't see that.
Either you have a bad rotor, corrosion at the hub/rotor face, damaged hub or your wheel bearings is shot. Hub runout of 0.0005" is considered acceptable. If its too high, either the hub itself is damaged and/or shot wheel bearings.
Thanks so much bmwpower/ cetialpha/overheated for the great advice.
So here's what I've done after reading everyone's posts. I've taken out the rotors and rotated the hub to measure runout and oddly enough, I have zero movements to the right or left on either side.
I can't speak on the bearings, but the hub doesn't seem to be physically damaged when I turn it to see any major movement. Is there anything I can do to check for bearing issues?
Additionally, I returned the rotors and to my surprise the parts rep tells me that somehow these particular rotors have seen alot of returns. kind of hoping the rotors are warped or defects.
Either way, I am looking to find suitable ones now based on the recommendations, however, I've also attached images of my hub to get your opinion on if I should be grinding the hub surface down further? or if theres something you can physically see that I should be doing.
That hub face is pretty rough... I’d clean it up with a grinder and cookie. I would measure the run on it. Minute amounts at hub, become amplified at the outer edge of rotor (due to distance).
Thank you to everyone!
I cleaned up the hubs and bought new rotors and reinstalled everything.
The runout seemed to be very minimal.
After taking the car for a spin, there was a very loud grinding sound coming from the passenger wheel. After hoisting the car, we noticed the balancer on the tire was loose and grinding against the rotor. Removed that, the noise was gone and all is well.
Again thank you to everyone for the suggestions and troubleshooting.
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