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Sorry for the silence, been getting the shop ready for my move.
Yes, they ran it on the lift in dyno-mode, as I did and yes, the clicking was loud (as in the video I took on page 1). This is why the indy and the dealer thought it was the slotted/drilled rotors. Once the brakes were back to OEM MB brakes, no noise. But once you get into the car, noise. I almost think that there were 2 noises. The one I hear in the cab and the one made by the rotors. Things seem to have changed a bit though.
The noise is seems intermittent now. The past few days, it's there initially after the car has sat for a while. As an example:
- Drove to work yesterday early. Clicking loud and evident when I left the hotel through 2 stretches where I drove between 30 - 40mph. I got onto the highway for 20 miles. Once I got off the highway, the car was silent in that mph range.
- Left work after 6 hours at around noon. The noise was back (although not as loud) for the first mile or so....then it was silent in that mph range.
Weird. It seems to be happening after the vehicle has sat for a while, which would lead me (who knows nothing) that it has something to do with maybe fluid settling (transmission or front/rear diff). Once the car has moved for a while, the fluid does it's job and the noise is gone. I also noticed that, when I hit a small dip in t he road, that the noise changed pitch with the suspension cycling. Could be, as before, my mind playing tricks though.
I cannot 100% say that this is the new trend or if it's been like this since day 1. I want to say it was more persistent before, but all this listening for noise has played tricks on me.
The car was indeed back at MB last week, so the techs could listen to it after it sat overnight. They did hear it in the morning and have narrowed it to the "drivetrain". As with my driving, they were unable to duplicate it again a bit later. They want it back Monday, so they can have it for a few days....it's now become their mission to figure out the cause at least. It would be interesting to see if it makes the noise in the morning when on the lift or not....i.e. does it need the weight and load of the vehicle to make the noise or is it always there.
1. Wouldn't surprise me if it's the bearings on the output shaft. Even though the u-joint could be good, those bearings are dry, maybe, then get nice and coated with fluid once I drive a bit. Makes sense.
2. Wouldn't surprise me if it's the center support bearing of the rear prop shaft. Perhaps the bearing and rubber isolator. causing the noise to go away as everything warms up and causing the pitch change when the rear suspension cycled.. Makes sense too.
Anyway, we'll see if they figure it out. Sorry for the ramblings, but I know you nerds love this crap as much as I do....lol.
On a sidenote, they did give me a 2023 EQS450 to play with as a loaner, that was fun.
Both the really good Indy here and the MB dealer are unable to diagnose. MB had it again since Monday...no joy.
Wheels up to VA at 0300 Thursday. Will just drive it until the noise is more consistent or something falls out of the bottom of the car onto the highway. I wish that was a joke, but that's where we're at right now. Or, I go the molotov cocktail route. This is my second MB and both have had an odd noise that no one could diagnose.....warm and fuzzies...not so much.
Just a quick update: replaced the front brakes yesterday (new Zimmerman coated rotors and TRW Ultra ceramic pads) and after properly bedding them in, I have yet to detect that faint clicking noise between 35-40mph. The rotors I replaced were worn pretty well, they were dimpled and slotted and quite rusty, having been on the car nearly 5 years. They required some hammering to knock loose, and the new parts went on very smoothly.
So far, no noise and the braking is excellent. As soon as I hear the noise again, we can definitely rule out brakes as the source.
Just a quick update: replaced the front brakes yesterday (new Zimmerman coated rotors and TRW Ultra ceramic pads) and after properly bedding them in, I have yet to detect that faint clicking noise between 35-40mph. The rotors I replaced were worn pretty well, they were dimpled and slotted and quite rusty, having been on the car nearly 5 years. They required some hammering to knock loose, and the new parts went on very smoothly.
So far, no noise and the braking is excellent. As soon as I hear the noise again, we can definitely rule out brakes as the source.
On another note... I've got new Zimmerman coated front discs waiting to go on once my front pads are out of life. Did you find it odd that they are the same part for left and right side? I mean the internal venting is directional so the internal vanes point in opposite directions when the discs are mounted. Seems odd to me. I have to assume, in this application, it makes little difference that there could be a small difference in disc operating temperature due to the vanes rotating in opposite directions but I can't imagine this being done on a "proper" sports car or a race car. Seems to be a cost saving measure.
And wow... those discs are heavy...
As an aside, picked up my GLK at the factory in Stuttgart 10 years ago today. Still on almost the original everything... tires, main battery, brake discs and pads, rear hatch struts etc. Only changed the Aux. battery, wipers, oil and filter, brake fluid and cabin filter.
I put Zimmerman on the fronts years ago with stock mb pads , no more dust to clean every week! But I wonder, the steel must be a harder grade , so braking performance is probably worse since they are not grabbing and deteriorating as as much . And mb pads last longer.
I put Zimmerman on the fronts years ago with stock mb pads , no more dust to clean every week! But I wonder, the steel must be a harder grade , so braking performance is probably worse since they are not grabbing and deteriorating as as much . And mb pads last longer.
If I recall correctly, MB had an optional pad and rotor change to ceramic front pads for W204 & X204 with a different rotor metallurgy.. The dealer made that swap for me after about the 10th complaint. The new stock pads you got may have been ceramic. The ceramics make virtually no dust and last a really long time. Otherwise, I would be concerned about the braking efficiency of using the same pads on harder rotors.
On another note... I've got new Zimmerman coated front discs waiting to go on once my front pads are out of life. Did you find it odd that they are the same part for left and right side? I mean the internal venting is directional so the internal vanes point in opposite directions when the discs are mounted. Seems odd to me. I have to assume, in this application, it makes little difference that there could be a small difference in disc operating temperature due to the vanes rotating in opposite directions but I can't imagine this being done on a "proper" sports car or a race car. Seems to be a cost saving measure.
I do find that odd, yes, but this has been the case for all of the vented rotors I've ever replaced EXCEPT for a set of Powerstop cryotreated ones I had installed on a BMW, which were clearly labeled L/R and the instructions pointed out which goes where and why. For all other OEM mfrs the venting slots were identical. I agree that on a road vehicle the direction of those vents won't make too much of a difference. I'm sure in the tracking/racing world that's very important.
Originally Posted by mkblue
As an aside, picked up my GLK at the factory in Stuttgart 10 years ago today. Still on almost the original everything... tires, main battery, brake discs and pads, rear hatch struts etc. Only changed the Aux. battery, wipers, oil and filter, brake fluid and cabin filter.
Do you keep your GLK garaged? If so, that contributes significantly to extending the life of many OE components. Also, very cool that you got to do the European Delivery thing. Perhaps one day I'll do it, unless the EU goes completely commie green and shuts down ICE vehicles' manufacturing altogether. And for those of you who may think that's harsh, I'm an immigrant from that part of the world, for a reason
Thanks for the info. Yes, I do keep it garaged so it has had an easier life than some. Have yet to wax it either, in the first 10 years, but the paint looks fine and is still shiny/glossy.
Better hurry... the E.U. does seem to be heading in the hug-a-tree Green direction - particularly Germany. I believe they want to ban I.C.E. sales in 2035 and start reducing fuel availability (essentially reduce gas stations) in steps, before then.
Originally Posted by andreigbs
I do find that odd, yes, but this has been the case for all of the vented rotors I've ever replaced EXCEPT for a set of Powerstop cryotreated ones I had installed on a BMW, which were clearly labeled L/R and the instructions pointed out which goes where and why. For all other OEM mfrs the venting slots were identical. I agree that on a road vehicle the direction of those vents won't make too much of a difference. I'm sure in the tracking/racing world that's very important.
Do you keep your GLK garaged? If so, that contributes significantly to extending the life of many OE components. Also, very cool that you got to do the European Delivery thing. Perhaps one day I'll do it, unless the EU goes completely commie green and shuts down ICE vehicles' manufacturing altogether. And for those of you who may think that's harsh, I'm an immigrant from that part of the world, for a reason
Sorry for the tread hijacking. I will keep an ear out for any new/clicking noise once I get around to changing the pads and discs (although the discs are not slotted). For whatever reason I bought Bosch brake pads. Probably due to good reviews on Amazon, or something like that - don't recall exactly.
With this harder Zimmerman rotor do I need to go to ceramic ? Yes I don’t think these stock pads grab as well as stock rotors !
Pads and rotors need to be matched to maintain the proper braking characteristics — friction coefficient, heat transfer, grab, fade, etc. I did it wrong a long time ago and my wife had an accident. I haven’t gone outside the manufacturer’s recommendations since.
Sorry for the silence....was moving cross country.
3 days before the move, torn inner driver CV boot. No way to get a new one in time, so the local indy threw in an aftermarket one, which sucks. When in drive and foot on the brake, I get a weird binding/vibration. Made the drive fine and no wobbles or shimmies. Reading a bunch of threads and talking to a shop here at my new location....seems that MBs do statistically not like some aftermarket axles. A few threads said the same thing about the vibration which immediately went away after replacing the aftermarket with an OEM shaft. OEM shafts are completely on back order everywhere. I ordered one from a GLK with 25k miles. I'll be re-booting the old one and selling it. Currently have a new boot on, just having an issue seating the tripod. Should have saved some money but at this point....it is what it is. I have a new MB intermediate shaft and bearing which I'll install at the same time.
Back to the thread
After the 1700 mile drive to VA...same clicky clicky...no change. Drive to and from work a few weeks and figured I'd wait til it got louder and easier to pinpoint. I'd ordered a motor mount and transmission mount kit a while back just to have. 2 weeks ago, I had a Saturday free, so I pulled the old transmission mount and compared it to the new one (pic below just for reference). I noticed that the rubber isolator on the old mount was quite a bit more compressed...maybe 1/8". I threw the new one on and thought nothing about it. Next morning I got to work and thought...wait a second....no clicky. Got back in....sure enough...silence. I crossed my fingers and to this day...no clicky. I'll call that problem solved, as the noise happened daily without fail.
My guess is that the slight compression of that isolator allowed the driveshaft to hang at a slightly different angle. Like MOA when shooting, an 1/8" at the mount would change to a larger number away from the mount. I'd mentioned in this thread that it sounded like a card in bicycle spokes. I bet that the different angle was allowing the driveshaft or something in the driveline to contact one of the 500 heat shields somewhere under the car, Is that correct, who knows. She runs great with regard to this issue.
Interesting indeed. If at all possible, we'd appreciate it if you could share any tips on replacing the mount. I replaced the front brakes more than a month ago and the noise had pretty much disappeared, but I did hear it the other day when I had a passenger in the car (usually I drive to work alone). I wonder if the extra weight - along with the collapsed mount - further angles the driveline to where it makes the noise.
Also, could you share the part# of the mount? I'd like to tackle it myself and see if I can confirm your fix
There are videos online for both. It's quite easy. Basically you want a jack under the transmission with a piece of wood on it to distro the weight...undo the bolts...swap mounts...and re-install the bolts. Sounds a bit un-detailed but this swap is quite easy.
07-16-2023, 09:27 AM
