Clunking Noise on Decceleration. Help.

[dubgli]

On the side of the road on my android, waiting for a friend to come and tow my car.


So i started to notice clunking noises from the front end as i deccelerate. I can only hear it when deccelerating and the noise seems to be dependent on the speed, so when i first let off the gas the clunk is fast and then of course as the car comes closer to a stop it clunks slower and slower. I took my wheels off, both fronts, and didnt notice anything out of the ordinary. No wiggle or anything. I tried reverse decceleration and no noise that i could hear. The car itself still drives normal and has not loss power. Im just choosing not to drive because i do not want my wheels or something from the front end to fall off as i drive.

[dubgli]

took me forever to write that. car is being towed already and im heading to friends house. i apprec any help.

[old guy]

First thing I would check for is excessive rotation in the CV joints.

[dubgli]

First thing I would check for is excessive rotation in the CV joints.

Okay. so raise the car, take wheels off, and by hand try to see if the CV axel rotates excessively? Is this the correct method? If so, i did that on the side of the road and did not notice any movement. Let me try again..

[old guy]

The way I check is to remove the wheel and then lower the front suspension onto a block that loads the suspension at the normal drive height then check things out. This way you have the suspension in the normal operating position. If you just jack the car up the CV joints are not in the "normal" and consequentially most worn position.

I also have a drilled 12" steel bar that I can bolt to the hub for adding leverage. You can do the same with a length of lumber. Just use something that is thin enough to drill a hole and attach with two wheel lugs. This will allow to to crank a little harder to check for excessive play in any direction.

[dubgli]

So did what you said Old Guy and there is NOT much movement.. even with a lever bar attached to the hub.. i if wiggle hard enough it might move what seems to be less than a cm.. upon inspection, the boots are all still intact and not torn as well.. while i was under there, i checked the sway bar and it seems okay to me. Bolts are still in and tight, nothing seems out of place with the sway bar.


whats next?

[old guy]

Did you happen to notice if the clunking changed when decelerating in neutral versus decelerating in gear?

[dubgli]

no, i tried both slowing down in neutral and in gear and the clunk is still there. and it seemed to be the same clunking..

[old guy]

Check your inner control arm bushings. Look for any tears or splits in the rubber. Grab your brake calipers and see if there is any excess movement. If the rubber bushings in the calipers go bad the calipers can rattle around. Take a look for any signs of leakage from the motor mounts. If they are leaking you will see a pink/purplish fluid around the base of the mounts.

[dubgli]

So no pink/purple fluid on base of mounts.. No caliper movement.. I do see some wear and tear on the lower Control arm bushings.. Everything seems pretty solid besides the bushing that i saw.. took it for a spin up and down the road going slowly and holy crap it sounds really bad and feels just as horrible. The clunk/knock noise is now accompanied by a metal on metal squeak.. what the heck.. if i replace the cv axel and the control arms, what are my chances of eliminating this sound? in other words, what else could it be besides those two things..?

[old guy]

Be sure to check your inner brake pads. If the caliper bushings are worn the inside pad can wear much faster than the outside pad. Might be where the "metal on metal" sound is coming from.

[dubgli]

let me make a video.. perhaps it will help a little bit..

[A4SoftWalker]

How are ur mounts?

Snub
Engine
Tranny (not so much this one)
Rear diff (not in ur case but important for rear clunk)

[dubgli]

i tried to make a video, but I could not record anything worthy.. (DAMN EXHAUST) .it's hard to hear it in the videos.. I didn't check the snub mount, but when i did the timing belt a few months ago it was still intact and in good shape.. the motor mounts seem okay, no purple fluid as old guy suggested.. i might just go ahead and replace cv axles and control arms. (FUDGE) this knocking/clunking is definitely related to something rotating upfront.. clunks louder and faster as the car moves faster. (not engine speed) if replacing control arms and cv axles does not get rid of the clunk, then wtf can it be? we'll see.

still feel free to suggest options.. thanks guys.

[dubgli]

is it possible that the CV axle is defective without a torn boot and leaking.. if so how often does that happen?

[Dan[FN]6262]

Tranny (not so much this one)

when my trans mount was ripped in 2 pieces, I had a hellish clunking noise on acceleration and deceleration

[road_tripper]

check and see if all your brake components (specifically calipers) are bolted (appropriately) tightly.

[dubgli]

Yeah, i guess i can take the calipers off and install them again.. I only tried to shake the calipers for movement which they did not have any, but its worth a shot.

Again, a recap of the symptoms..

- Clunking noise and vibration on deceleration
- does not matter if in neutral or gear coasting
- clunk is speed dependent, not RPM

[A4Maine-iac]

I had the exact same issue a while ago. Noise on deceleration in gear or coasting. Left turn was louder right turn went almost away. Turned out to be a semi stripped lug. Looked at the wheel to hub and on the left rear there was a 1/4 of a inch gap. New lug and went away. See if noise is consistant left and right turns. and inspecked each wheel to hub.

[dubgli]

Thanks A4Maine. I will check the lugs, although, I've taken the wheels off a dozen times now since the clunking and did notice anything.. Probably because i haven't been suspecting it.

[A4SoftWalker]

when my trans mount was ripped in 2 pieces, I had a hellish clunking noise on acceleration and deceleration

Welllll - technically the man did mention a clunking UP FRONT not under the car.
That is why I decreased the importance of the mounts going to the rear of the car.
Any of those mounts ripped or degraded will cause a horrible clunk.
... but those dont seem like the problem in this case.

GOOD u have narrowed the issue down to a rotational based issue.

Also check for any signs of rubbing/scraping in there. Gud Luk

[Dan[FN]6262]

Welllll - technically the man did mention a clunking UP FRONT not under the car.

trans mount is in front of the driver

[A4SoftWalker]

trans mount is in front of the driver

Thread Jacker Extraordinaire...

[dubgli]

WTF! so today the clunk got really bad. I thought the noise was coming from the front passenger side so i focused on that side, but decided to go back to the driver side wheel and what the heck do you know!? The wheel is loose. so i torque it back up and the clunk is noticeably better if not gone, but in a matter of seconds, the clunking comes back ever so lightly.. a minute into the drive and its starts to get a little louder and then it just becomes noticeable again. I check the wheels again and its not loose.. so i drive again and the clunk is there as well as a squeaking noise.. now i notice if i apply the brakes at the right pressure, i can stop the squeak and the clunk.. So maybe a brake job and i'm good??

[A4SoftWalker]

Why did this loosen?
Do u fllw Bentley/OEM specs for all ur torque values?

[dubgli]

Why did this loosen?
Do u fllw Bentley/OEM specs for all ur torque values?

i think it loosened because my car is just too powerful. All that power and speed and i think the lug bolts just started to back out..

[dubgli]

but seriously, i don't know.. its never happened.. i usually torque them to 100 lbft.. its what my wrench is set to and i'm sure i may push pass the click a little.


I took off my calipers and i didn't notice anything different.. still plenty of meat left.. the car stops fine.. i guess i'll do a brake job before i do the axles.. i think the axles are probably fine as i didn't notice any tears..

im thinking its something with the calipes forsure now.. if i step on the brakes it gets rid of the clunk and squeaking.. i think before, the wheel was loose and no matter if i stepped on the brake or not it would clunk.. now that the wheel is tight, only the brake clunks.

[A4Maine-iac]

Hmm check the back of the pads also the metal clips will fall of sometimes and cause this. I would take each pad out and inspect.

[dubgli]

yeah, i will take them off today.. I have the b5 s4 brake setup. Maybe i'm not torquing the wheel bolts enough? initially when i found the wheel loose and retightened the wheel, it got rid of the clunk on deceleration for a few seconds and then it seems like it just got loose again..

time to look for some rotors/pads//

[dubgli]

so a coworker examined the clunk and suggested that it could be a wheel bearing.. If it was a wheel bearing, would pressing on the brakes make the clunking stop?

[A4SoftWalker]

^^^It made noise when I had 3 different instances but wheel bearings are funny things.

Mine would howl and make a dull scraping noise. Some days worse than others.

I dont think a wheel bearing can make a clunk because it is by its very nature sealed.

A wheel bearing that is real wobbly can cause a clunk on the externally mounted hardware I would assume.
Depending on how bad the bearings are - a clunking bearing will be a VERY wobbly one. Check for that.

[dubgli]

okay.. so question, when you raise the car and take the wheel off, the shock mount bolts seen under the hood should not be loose at all correct? as i took off my calipers, i decided to look under the hood and notice the mount bolts were about a cm off of the surface..

[old guy]

okay.. so question, when you raise the car and take the wheel off, the shock mount bolts seen under the hood should not be loose at all correct? as i took off my calipers, i decided to look under the hood and notice the mount bolts were about a cm off of the surface..

They should not be loose. I believe you may have found your problem. By shock mount bolts I assume you are referring to the three bolts that hold the upper shock mount assembly to the uni-body frame.

[dubgli]

okay.. now does the bolt head just tightens up against the surface? or is there suppose to be a washer of some type.. I've only tried one bolt and it keeps on spinning.. please tell me it's not stripped..

[old guy]

okay.. now does the bolt head just tightens up against the surface? or is there suppose to be a washer of some type.. I've only tried one bolt and it keeps on spinning.. please tell me it's not stripped..

Are you referring to one of the three bolts that secure the upper shock mount? Those bolts should definitely tighten up when turned.

[dubgli]

Are you referring to one of the three bolts that secure the upper shock mount? Those bolts should definitely tighten up when turned.

yes, those are the bolts i'm referring to. the two bolts closes to the ecu box are tight, but the one bolt by the coolant reservoir just keeps spinning.. I did notice that the equivalent bolt on the passenger side has a washer and this one bolt I'm talking about does not. I find it hard to believe that the washer just fell off. I tightened what i could and went for a drive.. the clunk has severely reduced, but you can still definitely tell that its there.. its very faint.

can i take that one bolt that keeps spinning out without jacking up the car? I want to place a washer there to help see if it will torque down and stop spinning.

[old guy]

can i take that one bolt that keeps spinning out without jacking up the car? I want to place a washer there to help see if it will torque down and stop spinning.

Yes you can. Unfortunately if it is spinning (stripped) adding a washer underneath it will not fix the problem. You will probably have to use a Time-sert, Keensert or Helicoil to repair the stripped bolt.

[dubgli]

Yes you can. Unfortunately if it is spinning (stripped) adding a washer underneath it will not fix the problem. You will probably have to use a Time-sert, Keensert or Helicoil to repair the stripped bolt.

okay.. a little extra help..? haha. i guess i'll just take the bolt and bring it to the store and ask for help with the correct size helicoil.

[A4SoftWalker]

I don't know for some reason I just love my Bentley that cost me less than 100 bucks.
We all love pics too.
I guess the number bolt are u referring to is "1"?
The tightening torque is there for u when u fix ur problem too in order to prevent it loosening again.

[old guy]

okay.. a little extra help..? haha. i guess i'll just take the bolt and bring it to the store and ask for help with the correct size helicoil.

Unfortunately it’s not quite that simple. If the bolt is indeed stripped you will need to drill the existing threads out before you can use a Time-sert, Helicoil or Keen-sert. I would recommend good ‘ol Google to find information on how to use one of these thread repairs. I am sure you can find numerous “How To” videos. It’s pretty straight forward.

There is another possibility. Take a very close look underneath the upper shock mount. You should be able to see where the three mounting bolts protrude through the mount. If there is enough room you may be able to use a slightly longer bolt and simply put a nut on the end of it. I have never tried this so I don’t know if it is feasible but certainly worth a look.

Good luck!