Hot_Fur

Time for everyone's favorite game....is it the output shaft bearing, maybe a branch in the wheels, jacked up parking brake?

Doing full brake overhaul Tuesday. Once I get that done, I'll be able to see if it's something to do with them. It's a click, not a whine or howl...so hopefully not an output shaft. Anyway, anyone had these symptoms?

- It's a clicking sound. Think a playing card in bicycle spokes crossed with the Jetson's spaceship.
- Audible at about 28 - 39mph...then dissipates.
- It's a very steady and uniform sound that increases with speed until it disappears.
- It's nothing from the inside...i.e. radio, climate control, leaf in the a/c fan or vent.
- When its audible, car into neutral and rev, no change....so only following the speed vs engine rpms.

Now let's see if anyone can picture it lol

Thanks in advance if I get anyone who's had this.

habbyguy

If it's a wheel bearing, it would probably get louder at speed - though tire and wind noise can drown out other noises at higher speeds. Taking a sharp curve or corner would change if it's a wheel bearing.

Having just re-rebuilt my transfer case, I'm just going to hope that's not it. ;-)

I'd suggest taking a look at the front driveshaft - it's kind of covered, but if you can move either end of it even a little, it's on the way out (moving the front means bad driveshaft - moving the rear suggests a bad transfer case output shaft).

But ultimately, if you can post a video / sound file of the noise it'll go a long way to helping us ID the culprit.

Hot_Fur

Sorry Habby......busy at work.

I put the car on stands and into Dyno mode. Noise definitely from the front....on both sides. With the wheels off, it's definitely audible at even 10mph and does not seem to dissipate when speeds are increased.

- New pads and rotors installed. Noise before and noise after (exact same noise). My guess is it's not anything with the brakes.....but....
- Noise seems to be coming from the caliper (both sides). Weird, because there's nothing in the caliper but a damn piston. Nothing is dragging on the pads, not the heat shield, nothing.....but wait....
- When I pull the caliper and pads......ZERO NOISE. Since I don't think anything in the caliper can click, could it be noise transferring from somewhere?

Could it be the CV axle? Having been through that on other cars, the CV outer joint tends to click when turning...this noise is when going straight. I've heard the inner joint can go bad and click when going straight, but what are the chances that it happened on both sides? Unless the noise is transferring through the shaft.

My indy thinks it may be the diff and it's transferring the noise outward through the caliper.

The buzz at about 50mph
https://youtube.com/shorts/0bOx0WwVluQ?feature=share

Is that CV shaft wobble normal?
https://youtube.com/shorts/BYP1AgQYCjs?feature=share

habbyguy

Interesting that the noise goes away with the brake pads / calipers off. A certain amount of brake drag can happen (especially if your guide pins are not clean and well-greased, or if you have a "sticky" piston in the caliper(s)).

I don't think that CV axle looks remotely right. With luck (relative term here...) it's JUST the CV axle and not the differential. If you can feel any movement in the inner CV joint, I'd say it's toast. Don't get confused by rotational slack in the differential though - that's normal.

And yeah, mechanical noises travel through metal in such a way that it's difficult to nail down the source very often. This is why everyone who owns a wrench should spend the $5 or so on a Harbor Freight mechanic's stethoscope. It really does take away 99% of the guesswork associated with locating a mechanical noise, though there really isn't any place to put it on a spinning axle...

Hot_Fur

Grabbed a stethoscope....hard to figure out what a good diff is supposed to sound like vs a bad diff.

Going to swap in new left and right CV axles and intermediate shaft next week. I'll also check play on the driveshaft. If the CVs don't fix it...may be the diff. I did some pricing today, not cheap but it is what it is. I'll probably grab a new front prop shaft if the diff has to come out anyway....will make swapping that thing much easier while the diff is out, vs while the diff is in down the road.

I'll update after the CV swap is done.

*Edit: Pulled all of the plastics. zero movement in the front prop shaft or joint. Joint and flange look clean

habbyguy

Good news that the transfer case and propshaft seem to be OK. Just look for any amount of "unusual movement" anywhere, and replace that part... ;-)

ChrisHimself

are your pad shims ok?

NYCGLK

If noise is going away when removing pads it's probably warped and/or grooved rotors. Any pulsation under heavy breaking?

Mmr1

“ when I pulled the caliper and pads zero noise”

ok, then that’s where you have THE problem.

John CC

Put the calipers back but leave the pads out. (DO NOT STEP ON THE BRAKE!)

Does it make the noise? If so, look for contact between the calipers and the disks. If not, look for problems with the pads loose in the caliper frames, or something contacting the disk.

Hot_Fur

No pulsation under braking. When the noise is there, braking does not change it, it only decreases with the speed of the shafts turning/speed. No vibration under load...nada...just the sound.

Noise was there with OEM pads and rotors installed. Noise is there after new pads and rotors were installed...no change. Makes sense that the problem would be in/around thebrake, but there's nothing. Not sure how it could be the caliper (both sides) as the caliper is a dumb part with only those 2 pistons...nothing to make a click. An indy that looked at it said its the new rotors (slotted and drilled)...but I swore to him that the same sound was there with the OEM set up. I've had other cars with slotted rotors that do make a subtle "whoosh" due to the air over the slots. This is a definite click click click. The reason I did the brakes was because I thought it might be a rotor or pad issue outright. Indy heard it on one side. When I advised him I found it on both sides, he leaned toward the diff and the sound expelling out through the shaft. His shop is a reputable Porsche and Mercedes shop....so not a local guy on the corner.

I even swapped out the new pads for another set, in case the shim was loose...no change.

Was going to check the axles. Pulled the pass side yesterday, came out with a few taps. Axles are good....now I can't get the axle back in....**** my life. I'm moving tomorrow and now have an axle-less paperweight....aaaarrrrgggghhhhh.

I can get the axle slid a bit into the diff. Turning it back and forth slightly it seems to catch the splines as it locks....It just won't go in any further. Gave up last night...will attempt it again this afternoon. I did drain the fluid and put in fresh fluid....yes, the right stuff.

Every video I've watched has the "little push and the c-clip just pops right in"....nope. No obstructions in the hole, everything clean......holy $**** I'm buying a Vespa....lol.

I thought I had it set last night. Everything was tight, both strut bolts back in, but there seemed to be a bind. Inner 3 bearings seemed to be in the tulip cup. Looked up from underneath and it definitely has to go in another 1 - 1.5 inches.

habbyguy

I did a video on pulling / replacing the front axles (and no, they didn't just pop in). ;-) Far, far from it, and I think the method I used will work for you (spoiler - put the axle into the hub, raised the suspension to more or less level, and drove the axle home with an impact socket laying inside the hub splines, while holding the inside of the axle against the intermediate shaft).

Hot_Fur

I've watched your video 8 million times....thanks for posting that by the way....

The part where you didn't film the passenger side install but it went right in.....I was hoping for that karma.....but no joy.

If I didn't have to have the car moveable by today, this wouldn't be so stressful. Having a buddy help this afternoon...fingers crossed. I'm at the point of just wanting to be able to get it onto a flatbed, down to MB or my indy, give them my amex card and say fix it and the clicking....I'm almost ready to throw in the towel....

habbyguy

What I've done (and tried to do on the left side) is to just swing the entire strut "package" outward, and then push it home forcefully, allowing the weight and momentum to force the C-clip home. I've done that successfully on several of my cars over the years. Worst case, try the same method I used on the left side (raise the hub to ride height / flat axle and push / hammer the axle with an appropriate deep socket and big honkin' hammer). If that doesn't do it, I have to wonder if something else is wrong - you might pull and check the condition of the C-clip. I've resorted to re-using the OEM C-clip when the supplied clip on the new axle was just a bit too fat to go in (without TOO much violence, anyway).

Good luck - and let us know if you end up leaving your X204 lawn ornament behind you or not... ;-)

Hot_Fur

LOL

Will do !!!

Hot_Fur

Done, well axle is back in and good. Gonna take it to MB and pay t hem to diagnose the clicking and then decide the next course of action after that.

Seemed there was a bind on the inside near the splines. We put a pry bar under the can and gently lifted it up...relieving the bind inside and it popped onto the splines, barely. Seated the axle stub into the hub, jacked it up so the axle was as horizontal as we could get it....couple of hammer taps and the ring receded...a few more and it went in and popped into place. Funny how the slight bind would not let it slide onto the splines....lesson learned.

Now, we'll see if the click is the diff or not.

calder-cay

Congrats on the bind fix!

Did ya get a chance to get a final diagnosis yet ?

Hot_Fur

Nothing final yet. Going in next Wednesday for a 2nd opinion...stay tuned.

Hot_Fur

So far:

Indy: It's your new front slotted/drilled rotors making the noise
Me: It made the noise before
Indy: It's your rotors
Me: Goes home, checks a bunch of crap, finds nothing. aside that it's coming from both sides.\
Indy: Not good, might be your front differential
Me: Shops around for diff pricing as I wait for the dealer for a 2nd opinion
MB Dealer: It's your new front slotted/drilled rotors making the noise
Me: It made the noise before
MB Dealer: It's the front rotors, your diff sounds fine.
Me: ****, I'm in a hotel until my move back to VA with sparse tools. Fine, redo the front with all MB parts and take my money
MB Dealer: Car's done. Test drive and in dyno mode on the lift, the noise is gone. It was your front rotors
Me: Awesome. I have enough tools to do the rears at work, so let me buy MB rear rotors and pads. I'll do them in the next few days so I have a full MB OEM brake set up.
Also Me: Leaves dealer - click click click click click click. Takes video in cab of noise and returns to dealer.

Test drive with head service tech only heard slight noise, not as much as before. He doesn't hear it in the car but does on the video....shrugs. I advised I'll do the rears and keep them updated. Left for work this morning. Click is back and as loud as ever.

So, doing the rear pads/rotors today...again. Since the sound goes away when removing the calipers, I'l replacing both front calipers this weekend....which will....fix nothing.

So, as I'm sitting, I have a clicking sound that neither a dealer or my indy can figure out. **** my life. Stay tuned

But, I did buy her a new set of OEM Bi-Xenon headllight assemblies. Mine had ridiculous crazing that was not buffable or repairable. Maybe if she can see better she'll be happy, or maybe it just soothes my OCD and will keep me from dropping a mysterious molotov cocktail into the back seat. They were super cheap (insert eye rolling smiley)

calder-cay

Utterly frustrating.

I guess, in this day and age of automation, if the mechanic doesn't see feedback on a "screen", they have no idea what to do. The days of touch, feel, sound, etc, for troubleshooting are on the way out, unfortunately...

Let's hope you get it sorted out !!

Hot_Fur

Movers packed my stuff, as I'm PCSing back to the east coast. Got the left rear rotor/pads redone today at work with limited tools. Caliper bracket bolt cross threaded on the right rear. It was a problem child the last time I removed it, but it managed to snug up. This time it's toast. GLK is at my indy getting that bolt removed/repaired and the front control arm being replaced (torn boot). He's gonna do a deep dive into the clicking again. Hopefully something to report in the near future or I just drive it until something really breaks....
When being used to having a full complement of tools turns to very limited tools while living in a hotel for a few weeks......I feel a bit lost not being able to do anything....aaaaaarghhhhhh

Currently debating on whether to chat with the dealer about the work they did which, obviously, did not fix the issue.

Almost plowed into an elk this morning at 70mph.....that would have resolved the clicking for sure.

Stay tuned.

habbyguy

Maybe I'm missing some nuance here, but a cross-threaded caliper mounting bolt could be the cause of some cyclic noise. And of course, noise is not always coming from where it SEEMS to be coming from because of the way it travels through the body (our ears are tuned to discern direction based on the speed of sound through air - it's MUCH faster through sheet metal, and sometimes a vibration in one area shakes something much bigger in another, making it sound like the source is there).

Mmr1

What a headache , I’m sure you had it on a lift and ran the motor in gear while listening ,

maybe spraying water on it starting with the brakes to see if the noise stops and to isolate it. Could help.

There are remote microphones systems you attach to pinpoint noise. Maybe a cheap Chinese unit is available.

or simply disconnect front brakes ,you have the rear! Just kidding of course. Good luck

andreigbs

OP: if it helps you feel better, you're not alone hearing that faint clicking noise. I too hear it, right around 35-39MPH and then it disappears. I've replaced rear brakes recently, no change. The front brakes are due soon, and they are the dimpled type of rotors (not drilled through), so I'll see if that makes any difference, likely not. It is a soft mechanical click, it doesn't vary with engine RPM or gear, so it isn't engine- or transmission-related.

As others have chimed in, it could very well be the front diff or the frontend of the U-joint out of the transfer case. Maybe it's worn enough to just make that faint clicking but nothing worse.

Also, if it helps, ours has been doing it for the last ~10K miles and not gotten any worse. I think if it's close to catastrophic failure I would expect it to get much louder, much faster, and to occur over a broader speed range than just 35-39MPH.

For now, I'm keeping an ear on it and that's about all.

Hot_Fur

Towel officially thrown in. Not sure I've ever been so annoyed or disappointed that a sound as obvious and that can not be diagnosed y a dealer or my indy. Maybe I'll try another place once I get to the east coast. I have 3 drives from CO to VA and back planned in the next few months for my move and hunting. Maybe I'll just deal with it until something explodes and then I'll know what the issue is.

Until then, some self love. Got the first headlight delivered. Will be installed after I get some PPF put on. Sidenote, dealer wanted the MSRP of $1250 EACH for these. Googled and found some at another dealer in the US for $1525 shipped for BOTH....yes, OEM, Bi-Xenon, ILS, yada yada yada.