[S4to335]

So, let me set the stage..had noticed this strange rattle/banging noise eminating from the LF wheel area...or left front portion of car. Noticed that over cobblestone pavement..you could hear it the worst. Over nice pavement..NOTHING. So, I decided to jack up the car in the driveway..take off all four wheels..and check stuff. So here is what I checked:

1) Brakes - is caliper mounted securely on the car? Yep. Does anything look strange with my Alcon BBK? nope. Does it have brake pads? Yes. Are they still intact? Yep... Is bracketry still mounted to suspension? Yep. Checked to see if rotor was still attached properly to the hat...seems to be.

2) Suspension - checked tightness on three top bolts...top nut on PSS9...bottom mounting bolt...sway bar mount...Nothing seems wrong here. I didnt however, take out the coilover itself and inspect.

3) Undercarriage - looked for tools mistakenly left under the engine, but on top of the undercarriage plastic...nothing I could find. Everything seemed fine.

4) Engine compartment - any tools left in there...? cant find anything that would cause a noise

5) Wheels/Tires - removed and inspected all four tires..nothing weird there.

So, off to the dealership I went..the BMW dealership to ask for their assistance. They checked what I checked..but also replaced the sway bar mounting bolts..since it looked like they had some wear. They noticed that my throw out bearing was making noise in certain situations but couldnt find anything else. Car was there for four full days. Chief BMW tech personally worked on my car. Nothing found.

So, now I am off to an independent shop..BMW guys. So I take it to a local shop of BMW club racers...and let them have a go at it. The only thing they find is that the bracket that holds the brake line..is rubbing against the uplink shaft..(hard to explain) but they bent it out...and that didnt change the sound. Then they said they thought the Ultimate Racing exhaust might be hitting on something under the car..adjusted it slightly..no change on the LF sound. So, I go with the owner on a test drive..and he definitely hears that the problem is still there...and that they didnt rectify it. We did notice that when brakes were engaged that the sound seems to go away over rough pavement. So, based on that we remove the Alcon caliper..remove the brake pads..inspect them..install a new set I happen to have..and then go out for another test drive. Oh, and we checked to make sure the little bracket that holds the brake pads in..is still operational...seems to be. We depress the brake pistons in..that works fine...one thing we did notice is that the brake pads arent long enought to go the full distance, top to bottom, in the spot they are installed in. Another thing tough to explain..but the pads seem to look like they could rattle up and down slightly. Maybe they could..maybe they couldnt..but it looked like they could.

So, this is today...I am going to try to get StaSIS engineering to look at my car (Alcon brakes specifically) the Friday before the weekend driving event at Infineon raceway with the Audi club..they might not have a space for me..we will have to see. I also dont think I could take this day off due to work committments..but who knows. I am just trying to rule out what it "isnt" to figure out what is causing this condition.

Wish me luck.

Oh..lastly...the owner of the last shop offered me a Dinan stage 2 tune ...might just take him up on that...WARRANTY BABY.

[kaleb]

Is there ANY way the upper strut mounts and related washers could be installed incorrectly? I am not familiar with PSS9 or anything. But I have heard of rattle problems from improper strut mount washer orientation, etc on other aftermarket suspensions. Just giving some thought.

[S4to335]

Originally Posted by kaleb

Is there ANY way the upper strut mounts and related washers could be installed incorrectly? I am not familiar with PSS9 or anything. But I have heard of rattle problems from improper strut mount washer orientation, etc on other aftermarket suspensions. Just giving some thought.

I havent had anyone REMOVE the coilover itself..that is also an option. My car has 27K miles..of which about 24K miles were with the PSS9s installed..this issue just started about 500 miles ago.

[kaleb]

No vibration in the steering wheel?

[scollins]

I'm thinking the noise is related to the two piece rotor, since you said the noise went away when braking. Two piece rotors can be noisy, although the info on the Stasis website says they've designed it to be quiet. With as hard as the brakes get worked on the track, maybe it has developed a small amount of play?

[sambonator]

I had some noise coming from my front suspension... found that the mounting point on my TEIN coilovers for the sway bar end links were lower than stock points... causing the bottom of the end link to hit the lower control arm at times. I replaced the stock sway bar end links with shorter aftermarket ones and the problem went away.

[BMWdrmz]

what about the front wheel bearing. I had this problem on my E46 M3 track car. Constant tracking wore out the bearing (I'm guessing). In any case I replaced the front wheel bearing hub assembly and the noise went away. In the end it looked like there was play in the bearing as the back end of the bearing has come apart so the front end of the assembly was sliding along the spindle. When I engaged the brakes, it prevented the assembly from sliding. Just a thought... good luck

[S4to335]

Originally Posted by BMWdrmz

what about the front wheel bearing. I had this problem on my E46 M3 track car. Constant tracking wore out the bearing (I'm guessing). In any case I replaced the front wheel bearing hub assembly and the noise went away. In the end it looked like there was play in the bearing as the back end of the bearing has come apart so the front end of the assembly was sliding along the spindle. When I engaged the brakes, it prevented the assembly from sliding. Just a thought... good luck

Well..I have had wheel bearings go out on my old Audi A4..and one of my Audi S4s..and on my Spec Miata race car...it is totally different sounding..pretty sure that isnt it..but thanks for the feedback.

BTW, the steering wheel does not vibrate.

[S4to335]

Not positive yet..but latest from Stasis engineering is that my alcon rotor is shot..the springs between the hat and the rotor no-worky. I will let you guys know if this is it.

[scollins]

Originally Posted by S4to335

Not positive yet..but latest from Stasis engineering is that my alcon rotor is shot..the springs between the hat and the rotor no-worky. I will let you guys know if this is it.

Damn, that sucks. Is this possibly a warranty replacement?

Looks like I may have called it though on the potential problem....

[S4to335]

Yep..you could be right...warranty maybe...if I bring my car to Sonoma to get it fixed. Working in SF and living in South San Jose..aint exactly close to Sonoma and StaSIS. Ugh.

[2e9x's]

If it turns out not to be the rotor...

Have people checked the suspension clearances with the car on the rack? If so, did they load the wheel to mimic the car sitting on the ground?

[kaleb]

Originally Posted by 2e9x's

If it turns out not to be the rotor...

Have people checked the suspension clearances with the car on the rack? If so, did they load the wheel to mimic the car sitting on the ground?

As you can see, everyone here is committed to resolving your problem!

[S4to335]

I know I have to corner balance the car now...the right rear is too low. the tow truck driver showed me how much it was off. The local shop that offered me the Dinan Stage 2 tune for a discount will probably do my cornerbalancing.

Thanks for the suggestions guys.

BTW, my new fuel pump was installed yesterday..and trying to pick up the car tonight...to work on this unidentified noise again.

[scollins]

Did you ever get the LF noise figured out? Was it the rotor?

[S4to335]

It was the springs inbetween the rotor and the hat...they degraded and were dirty..they could replace some of them..but not all...but when they did..the sound went away.

[scollins]

Originally Posted by S4to335

It was the springs inbetween the rotor and the hat...they degraded and were dirty..they could replace some of them..but not all...but when they did..the sound went away.

Excellent!