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2012 C300 Noise while accelerating and metal pins on splash shield?
I was driving my 2012 C300 out of my neighborhood a few days ago when I heard a noise thaf sounded like it was coming from under my feet. The noise sounded like something rotating was tapping something else, would increase in speed as I accelerated, and would disappear when I let off the gas and was coasting. The noise was audible with the windows down. I turned around and parked the car in the garage. The next day, I put the front of the car on some ramps, thinking the splash shield had been dented (thanks to the new super tall speed bumps at the grocery store), and was rubbing up against a driveshaft or something. The front (plastic) shield did indeed have a roughly speed bump shaped curve across the entire shield, just behind the front wheels. I unfastened the front shield towards the back of the car, and unfastened the center shield towards the front of the car. When I did that, I found several small metallic looking pins (one unbroken, several apparently broken) rolling around the shields. They are about 1/16 inch in diameter, and 3/8 inch in length. Anyone know what these are or where they would have come from? Planning on taking the car to the shop, but wanted to see if anyone else could identify the pins or source of the noise, and to see whether the consensus was that the vehicle can be driven to the shop, or if it needs to be towed. In the picture, the pin to the right of the dime appears to be unbroken. The left side is pieces of the pins.
This "pins" are the roller bearings probably from the prop-shaft UJ. If it is 4-matic then it could be one of the front prop-shaft UJs.
I would not drive it for than a mile or two as you may do more damage
Last edited by alecmascot; 05-08-2023 at 11:15 AM.
This "pins" are the roller bearings probably from the prop-shaft UJ. If it is 4-matic then it could be one of the front prop-shaft UJs.
I would not drive it for than a mile or two as you may do more damage
It is indeed a 4matic.
So you think it could be the bearings from within a universal joint? Could you provide a link for a similar part (if not THE part) you think it is? That way I have some possible backup information when I go to the shop. I'm not super familiar with the shafts and bearings, etc...as I typically let a shop handle any work like that, and I stick to doing the basic maintenance stuff, so I am having trouble identifying the parts you are referencing when looking on Google.
I was kind of thinking it could be from within the driveshaft support bearing, if the u-shaped bracket that holds the support bearing in place got damaged when the speed bump hit the bottom of the car. Would that make sense?
Those are U-joint bearings, probably from the front prop shaft like alecmascot said. If that lets go, it can cause a lot of expensive damage. Don’t drive it at all. Put it on a flat bed for transport to the shop.
Sorry..somehow had 4Matic front axles, not prop shaft, envisioned. U joint failure...greater than 100K miles and live where salt,slush prominent ?
108k miles, but no salt, and rarely ever snow or slush. This didn't start until I went over a speed bump slowly and the front of the car smacked down pretty hard onto it after the front wheels went over it.
Ordered a borescope to take a look around and see where I see damage. Planning on just loading it up (on a flat bed) and hauling it to a shop nearby once I can figure out roughly where the problem is. I would haul it in and let the shop figure it out, but I don't live near a MB dealership, and most of the shops nearby like to get...creative...when they are diagnosing your vehicle, unless you tell them specifically what you want done. And even the closest dealerships have pretty bad reputations for their service departments.
Towed the car to a mechanic. They are putting a comprehensive estimate together, but the primary part they said needs to be replaced is the front driveshaft. I am going to call them back and get more information, as they said there are a few things that they see should be done, but they are quoting right at $4k USD for just replacing the driveshaft. They said the transmission has to come out to do it, so it is labor intensive (not sure I agree with the transmission needing to be removed...I think you can just lower the transmission, and move it a few inches, per the 3 or 4 videos and threads I have seen about replacing it). They said several other things they saw would need the transmission removed to do anyways, so I'm not sure if they're adding a lot of extra labor for the trans removal in order to persuade me to get the other stuff done or what. Driveshaftstore lists the shaft at less than $400 USD, and $3600 in labor for the replacement is extremely high for what it entails. Even assuming they used an actual MB part, I would assume that would be $1500 or less, which would still leave $2500 in labor.
Going to get their comprehensive estimate, see what all they're recommending, and probably call around to get some other quotes.
I'm still not 100% sure where the needle bearings came from. The driveshaft did not appear broken at the front end, near the UJoint, despite finding a few needle bearings just underneath that point.
The mechanic put together the rest of the quote, including about $5300 USD worth of front suspension work (for a grand total of about $9000 USD). While I agree with some of the suspension stuff they listed, I think others are just listed since they would already be in the area anyways.
With that in mind, a shop I have used before is willing to just charge labor for replacing the driveshaft (they estimated between 3 to 6 hours), if I provide the driveshaft itself. I think that is a reasonable amount of time, based on the instructions found here and the videos I have seen of the driveshaft being replaced, so I am leaning towards going this route. Apart from the driveshaft itself (link to what I am planning to buy at the end of the post, in case anyone has a different recommendation), is there anything else I should have them change while they're swapping the shaft? Flex disks, maybe?
05-08-2023, 07:25 AM
