If you do a forum search, you'll see a lot of complaints on this issue. Some people know why it happens (and others guess) - but in the end, I dont' believe there is much you can do about it except have Lexus grease up the brake calipers. Or, if you really bitch at them a lot - perhaps they might replace your rotors + calipers (I think I read one example where this was the case). Then there's always aftermarket.
I get the clicking noise much more often when I go through slow turns; combine a slow turn down a slope (such as in a parking garage) and then you can really hear those suckers. It's annoying. Should it happen on a Lexus? No, I really think it shouldn't. Is there much we can do about it? Probably not. Sorry dude.
Its wierd......my IS has it, but only on the front left. I seem to recall having problems going through pads alot faster on that side.I am gonna go either Supra TT upgrade or aftermarket BBK.....eh,its just the price you pay to drive the IS I guess. I would rather have this problem then the butt load of dealer issues going on in the domestic market recalls of ford, chevy and dodge.
I don't know you guys, but I'm trying to make lexus to fix the issue under the warranty. Some of you're gonna say that this is the wearable item and therefore is not covered. Stuff like that shouldn't take place, especially at less then 10k miles. I've had 7 cars before this one, and never experienced such annoying noise.
Finally something I know about to give back to the board...
I bought my CPO 01 in the spring and immediately wondered about the off brake clicks. Turns out it is the sound of the calipers resetting/locking and it is loudest in the AM when backing out of the garage and shifting to Drive. During the day I can sometimes notice it but have gotten used to it.
At the time I did bring the car to Lex for warrantee service because I was worried about the clicking and that the brake feel was sloppy and slow, required too much pedal. Because of the brake feel issue they popped all new pads and rotors on (CPO warrantee rocks). This slightly reduced the clicking sound noise but not really much. The brakes have been great ever since and I got used to the clicks.
BTW, I really like this car, the new IS looks hot but I'm keeping this ride for a while! Can you imagine-trouble free since that episode at time of purchase - 6 mos and no trouble. My 2000 BMW cost me over $3,000 in the 6 month period after it went out of warrantee and before I swapped for the IS!!
The reason for the noise is when the brake assembly is cold, the pads and calipers havent expanded because of heat yet, what happens is the pads will clank against the caliper. Notice if you roll forward then brake, then roll forward and brake again it wont clank twice, this is because the pads are already shoved against the trailing edge of the caliper. Ive seen this problem on a few cars, and it was near maddening on my RX7 at first, but it wont have any affct on performance.
anorexicpoodle described it best. This is especially true with worn pads that have more play. Know that this also happens on the GS as they have the same brakes! Fresh pads with some fresh moly lube will stop the noise but it's a non-issue to me. Stop being a worry wort and enjoy the car.