Spiffyjiff

and yet another sound you are ridiculously being asked to diagnose sight unseen. anyway...

the best way i can describe it is "metallic popping". and here's what i know:

• it does not happen every time i drive the car, and if it does happen, it occurs only once per ride/outing and usually near the beginning of the ride. i.e. as if something is "snapping back into (or out of!) place" and remains that way for rest of the ride.
• occurs when first applying foot to pedal. literally, as i am initially applying pedal pressure
• it's pretty loud, and can def hear it without turning music all the way down.
• seems to be a slight "feel" also, not just the sound, as if i can feel the vibration from the "hit" or whatever. but this is very slight
• seems to be coming from center or slightly toward passenger side of car, and close to firewall (but unsure if under dash or in frunk/under battery area, etc)
• bottom line of good news: brakes work wonderfully/"like normal" whether i hear this sound or not so it doesnt seem (yet) to be affecting performance

i hope this helps generate some idea of what it could be. also helpful would be for someone to tell me what happens between brake pedal and master cylinder? are there levers, cables, interconnecting rods, what? (or could it be on the other side: something happening as result of pressure from cylinder to brake caliper?)

thanks all!

997_rich

Are you sure that it happens only with the foot on the pedal? Maybe the rotors are just wet and the pads are stuck and it's just the first time you ride off? or does it happen only upon the first stopping sometime down the road?

does it happen when stopping in forward and reverse?

Spiffyjiff

yep, i know about the stuck pads, that's def not it

not sure if this is where you were going with your last question but...i think it's the pads "rocking" front to back, as i just noticed an hour ago that it happens only once right after i switch direction fwd/reverse. after i backed out of driveway, i applied little pressure - pushing pads clockwise - then my first brake application when driving fwd, i heard the clunk - pads now going counterclock. i could actually duplicate this a couple times by just going fwd/reverse in my street for a few mins. i'm pretty sure it's the pads reversing their direction and knocking against...whatever.

i will check everything tonight, but as i said, nothing seems to be wrong with actual brake performance. could the spring clip holding the pads be at fault? i did change them an awful lot during DE season. could something else be loose/worn down?

Nugget

Sounds like the noise of the pad breaking loose from the rotor which happens often after washing or if you park the car while the rotors are wet from rain.

alexb76

+1. It happens to me if I drove it after a rain and parked it wet. Don't apply hand brake, that helps... but otherwise normal, rotors are just stuck and get released.

cajuncroc

My 06 Cayman S does the same thing. Once the brakes get hot, the "pop" goes away.

Spiffyjiff

nope, not the wet/stuck rotor thing - believe me, i know the diff. THAT happens to me everytime i wash the car. (and havent washed or driven in rain in weeks.)

yeah, i'm thinking it may be a cold/seasonal thing. i cant reproduce sound when car is warm BUT if i drive, then park for a bit to let car cool, i can get the sound by going from fwd to reverse or vice versa. it's like the pads are "readjusting" to the new position depending on rotating direction of brake rotor.

997_rich

Could be, or maybe the pad material itself is broken off the backing and that allows the pad backing to stay in place but the friction material to move clockwise and CCW slightly.

Easily checked if you jack it up and pull the wheel and examine.

Spiffyjiff

people, people, people...this is driving me *@%$# NUTS!!!!!!!!!!!!!

today i put the car on stands, took off the front underpanel and checked/tightened EVERY bolt i could find. none were loose. i checked calipers and rotors - both seemed tightly attached and fine. i checked pads and pad material - all looked fine. i also took off panels around master cylinder in frunk and nothing seemed loose or out of place.

like i said, i can reproduce the sound but only when switching direction (fwd/rvrs), and only hear the sound the first time i apply the brakes after switching direction. after that, no issue until direction reversed again and brakes applied again. does anyone else have any other ideas what could be causing that..."clunk"??? could it be because i put new rotors on but not new pads??? i'm just not sure about my earlier theory about pads "re-seating" clock/counterclock or whatever, when switching direc. i say this because, when fully assembled there just doesnt seem like that much play (up/down, side/side) is available in the pads to make that sound.

my next steps are to: 1) remove dampeners, see if issue is still present, 2) remove dampeners, replace street pads with pagids to see if issue still present.

this is so annoying that i cant figure it out!!!

sorry to be a whiny b*tch, but i hate when i cant diagnose an issue (that i can actually recreate at will, no less!).

TerpsRED

This is going to sound dumb, but are you sure you don't have something loose in the front cargo area that is sliding to the rear, then to the front under your first braking? Maybe the battery is loose in it's cradle? I'd check every cargo area for loose stuff, then move to hidden areas like the battery areas, then to the rear in the engine bay. Just a thought.

Macster

Last thing touched is first thing suspect...You must be very sure the calipers are properly installed and the hold down bolts torqued down properly.

My next check would be to ensure the pads are the correct part number and are inserted in the cavity in the calipers correctly.

At the same time you want to verify for at least the wheel from which the noise is coming from the pad retaining spring and pin and its lock clip are all in good repair and each is properly installed.

Sincerely,

Macster.

Spiffyjiff

believe me, "me being dumb" is th FIRST thing i tried to rule out! :P yep, checked batt tray, checked everything else that might be loose in frunk and under plastic panels - including brake reservoir, strut tops, etc.

in fact, while moving fwd (after applying brakes in rvrs, then switching back to fwd, of course) i can reproduce the sound while accelerator engaged just by tapping slightly on brake. i.e. just before the throttle sensor shut-off kicks in due to brake application, and before force from slowing is produced, i can get the sound to occur. thus i ruled out "shifting cargo". even when i dont test with the accel pressed, it's literally at the beginning of the brake application, before any slowing force produced. (unfort, another nod to the clock/counterclock pad diagnosis, since any shifting there would presumably only take a bit of pressure).

TerpsRED

well you got me. Unless it is a jammed caliper piston that frees up. but that would not be reproducable going back and forth during one driving session. It sure does sound like a loose totating component. I guess a trip to the mechanic is in order... Sorry to say.

onefastviking

Sway bar link going bad and has some play ?
Shock top ?

Let us know what fixes it.

MUSSBERGER

Do you use your parking/e brake?