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There was some tar type stuff piled up on the road that I could not avoid about two weeks ago. I took the day off for doctors appointments etc. today and decided to take the wheels off to clean the tar crap off under there. Car wash water jets would not take off the tar crap and I couldn't get my fingers between the wheel spokes far enough to scrub.
I also wanted to look around because I have a slight periodic feel, sound. Hard to explain, but the feel you would feel if you had a bent wheel. Kinda like that, but not as strong. I figured something might have gotten jammed up under there from that tar crap. I could not see my brake pads clearly either and wanted to make sure my pads weren’t worn. I know about the sensors, but wanted to look anyway.
Anyway, the wheel I thought might be bent is not. Strange. Inside, or outside nothing, but I did see this groove on my rotor. Since I am not a mechanic I do not know if it is supposed to be there. It is a kinda cut out/groove in it. See pic.If it isn’t supposed to be there that may likely explain what I feel. Side note, the feeling is much harder to notice at high speed. Slow speed it feels just like a bent wheel and is noticeable.
I will check back in a bit once I get the other wheels off. I will see if any of them or bent, or if the other rotors have the cut out I mentioned. FYI about a month ago I did hit a pothole that I thought caused this sound. Maybe, maybe not.
Please check back later to see if I found any of the other wheels bent, or for that cut out info.
Thank you in advance.
update:
There are no bends in any of the wheels, inside the wheel, or outside. The cutout in the rotor I asked about are on all rotors, so normal.
Now I am weirded out, because now I can’t explain what the bobble/fake bent wheel feeling or sound is from. I guess it could be a tire issue, but my tread is still good and I have no tires bubbles.
Oh crap, I literally just thought of something. A wheel weight(s) may have come off when I hit the pot hole. That would explain that wheel bend feeling, but I guess not the sound. I need to check.
Last edited by ThatsMyDawg; 03-22-2023 at 10:45 AM.
When does noise occur?
accelerating?
Cruising constant speed?
Coasting?
Braking light and/or hard?
Does car sit for long periods without moving? FLat spot tire goes away as it warms and drive
Engine RPM when it occurs?
DO you feel it in butt or hands or both?
In mean time:
check tire tread for stuck tar or such that could make it out of balance.
Have tires balanced and wheels checked for true and round.
Feeling and noise occurs when accelerating, constant speed, decelerating and coasting. Very hard to feel/hear at highway speeds.
Braking light and/or hard? No change when braking. This sound and feel remains the same no matter how hard, or soft I break although I "feel" it's a little more noticeable when I am turning.
Does car sit for long periods without moving? No. The most it ever sits is a week. Driven daily except when rain is expected.
FLat spot tire goes away as it warms and drive
Engine RPM when it occurs? It seems to start at 1k, or slightly below. The road I was on was so loud that it was hard to tell. I will check tonight when I am back on my quiet hometown roads.
DO you feel it in butt or hands or both? I feel it in the steering wheel and kinda in the pedals (kinda) Nothing in the butt lol.
In mean time:
check tire tread for stuck tar or such that could make it out of balance.
I saw nothing in any of the treads.
Have tires balanced and wheels checked for true and round
Yes, I didn’t think to check the wheel weights when I had the wheels off the car the other day and I can’t see back there enough with the wheels back on to check the weights. Good idea to check to see if they are still balanced. This only started happening about a month ago after I hot that pothole, but I didn’t get a chance to check it out officially yet. Tire shop is next on the list.
.
Thanks for the suggestions and for reading my post
Last edited by ThatsMyDawg; 03-22-2023 at 03:13 PM.
Its always difficult to diagnose from driver descriptions (and the internet) but, I remember your car has 140k or so.
A few things to check at that mileage:
I agree that online can be tough trying to figure out an issue. Any ideas from those of you online are way more than I would have come up with on my own for sure.
I don’t quite have 140k yet, but it is approaching in due time. On my next A service (doing soon) visit to MB I will ask them to take a peek and see if anything stands out, but I am going to have the tires checked first to see if they are still balanced first.
Not being any sort of mechanic if I had to guess based on what I am feeling I say it’s gonna be a tire issue.
Originally Posted by crconsulting
Its always difficult to diagnose from driver descriptions (and the internet) but, I remember your car has 140k or so.
A few things to check at that mileage:
Flex Discs F&R. (Sounds familiar. I think I had that replaced prior. (May not be the same thing) I am talking about a part that goes between the transmission and where it connects. It makes a thump sound when changing gears when it starts to go bad. The transmission moves when it starts to disintegrate. Whatever that was called it was replaced.
Front & Rear Suspension (good idea, but no abnormal tire wear)
Motor mounts (I would hope they would have mentioned they looked bad when they had my engine out a few years ago, but ok.They could have went bad since then. Not sure why I would hear/feel something when coasting and no dead pedal if it was the motor mounts, but I will check. )
Half Shafts (doubtful)
Never heard of that, but I will ask..
Thanks for the suggestions, I will check them out.
Last edited by ThatsMyDawg; 03-22-2023 at 03:17 PM.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Hitting a pot hole may have messed up the wheel alignment. Did you notice any unusual wear signs on the tires? It may be too soon to see any, but misalignment can cause uneven wear that will eventually show up.
I looked at all four when I took them off and I didn’t notice any uneven tread. I also saw no bends in the wheels which is still shocking to me based on what I am feeling when driving. My steering wheel still rides straight and if I take my hands off of it at speed my car does not drift to either side. I don’t know what the heck is going on, but I do know it’s something. Each day I get in the car and hear and feel whatever it is it drives me crazy. If it’s not a wheel/tire thing then I guess I dunno.
This afternoon I am going to a tire place and have each wheel pulled and checked for balancing, or something else I may not have seen. If I do all that and my wheels/tires are still balanced and true, etc. I am going to be pissed, because that means it’s a MB trip.
Thanks for checking in. Will update later today.
Originally Posted by JettaRed
Hitting a pot hole may have messed up the wheel alignment. Did you notice any unusual wear signs on the tires? It may be too soon to see any, but misalignment can cause uneven wear that will eventually show up.
you may want to have the dealer do an alignment.
Last edited by ThatsMyDawg; 03-30-2023 at 11:13 AM.
Well, there is a tire issue after all and evidently an alignment issue. When they took the front wheels off there was uneven wear on the inside of the front tires.The drivers side was more worn than the passenger side, but both sides were worn. I must not have noticed because I was looking more in the middle of the tire and on the outside, not the inside. I was also rushing to get the wheels off, so I guess I didn't see the worn areas???
They rotated/flipped and balanced the front tires and I immediately heard less noise and less of the thumping feeling, but it's still there just not as bad. So I will get an alignment and see if that helps. I will try to get as much use out of these tires before getting new ones. I will wait to confirm all is well after the alignment first.... Still shocked that I had no crooked steering wheel, or car drift, but somehow I need an alignment based on tire wear. Strange, but I guess that pothole ws the cause for all this.
Last edited by ThatsMyDawg; 03-31-2023 at 06:48 AM.
Well, there is a tire issue after all and evidently an alignment issue. When they took the front wheels off there was uneven wear on the inside of the front tires. The drivers side was more worn than the passenger side, but both sides were worn. I must not have noticed because I was looking more in the middle of the tire and on the outside, not the inside. I was also rushing to get the wheels off, so I guess I didn't see the worn areas???
They rotated/flipped and balanced the front tires and I immediately heard less noise and less of the thumping feeling, but it's still there just not as bad. So I will get an alignment and see if that helps. I will try to get as much use out of these tires before getting new ones. I will wait to confirm all is well after the alignment first.... Still shocked that I had no crooked steering wheel, or car drift, but somehow I need an alignment based on tire wear. Strange, but I guess that pothole ws the cause for all this.
It’s my understanding, and from experience, that the aggressive negative camber setting on these vehicles causes inner tire wear--especially on the rears. As the tire approaches end of life, you may get a rotational thumping sound relative to speed. I experienced this last year. It’s been suggested that increasing rear tire pressure—the fronts are not so much of a problem--by 2/3 psi helps prevent the uneven wear (see link below). https://mbworld.org/forums/sl-class-...toe-issue.html
It’s interesting to note that, like yours, my drivers' side front tire was the one showing the most inner wear.
During the alignment, it was discovered that the drivers' side front did not meet the camber spec. It was 0.3 degrees too negative. Apparently camber is fixed on these vehicles and cannot be adjusted; however, MB has a camber kit that they installed. From their explanation it’s basically a simple eccentric bolt. Once installed, the camber was adjusted to within spec.
Last edited by hornethandler; 04-14-2023 at 01:12 PM.
It’s my understanding, and from experience, that the aggressive negative camber setting on these vehicles causes inner tire wear--especially on the rears. As the tire approaches end of life, you may get a rotational thumping sound relative to speed. I experienced this last year. It’s been suggested that increasing rear tire pressure—the fronts are not so much of a problem--by 2/3 psi helps prevent the uneven wear (see link below). https://mbworld.org/forums/sl-class-...toe-issue.html
It’s interesting to note that, like yours, my drivers' side front tire was the one showing the most inner wear.
During the alignment, it was discovered that the drivers' side front did not meet the camber spec. It was 0.3 degrees too negative. Apparently camber is fixed on these vehicles and cannot be adjusted; however, MB has a camber kit that they installed. From their explanation it’s basically a simple eccentric bolt. Once installed, the camber was adjusted to within spec.
By the way... After 4 new tires installed and alignment carried out, the service manager failed to mention that the drivers’ side front wheel did not meet the alignment spec. I picked up on it after reviewing the work order results (before and after alignment values) and brought it to his attention. He initially said it wasn’t out by much (-0.3) and I shouldn’t worry about it. He may be right, I don’t really know. After I calmly stated that the vehicle is under warranty and doesn’t meet factory spec., he advised me of a MB camber adjustment fixture that he would order and install. The fixture was installed and the subsequent alignment was successful.
“In God I trust, all others bring data.”
Last edited by hornethandler; 04-14-2023 at 01:15 PM.
So it was an alignment issue that was causing my rough ride. I guess that big pot hole I hit got everything all whacky. Since I had to drive like that for almost 2 months and the fact that my tires were already a few years old caused them to wear rapidly on the insides. MB got everyone back in line and I am riding smooth as I use to be. MB said they recommend a yearly alignment, but I have never gotten a yearly alignment on any vehicle I have every owned. Not sure if you guys do that?
So it was an alignment issue that was causing my rough ride. I guess that big pot hole I hit got everything all whacky. Since I had to drive like that for almost 2 months and the fact that my tires were already a few years old caused them to wear rapidly on the insides. MB got everyone back in line and I am riding smooth as I use to be. MB said they recommend a yearly alignment, but I have never gotten a yearly alignment on any vehicle I have every owned. Not sure if you guys do that?
Glad you got it sorted out.
Alignment is a good idea when installing new tires, especially if the old ones are showing uneven wear.
03-20-2023, 03:37 PM
