New Brakes "Clunk" When tapping pedal

[mherrema]

Very odd issue. I've spoken to several people in-the-know, everyone seems mystified. Here's the deal. I recently replaced both rear calipers as well as the front pads and rotors. I kept the existing rear pads and rotors as they were only 1.5 years old with not even 20K on them. Front calipers stayed as well as they are in good working order. I bled the system out and the brakes work fantastic, as expected. No issues whatsoever at speed or through any other kind of use, except for below.

Now for the "trouble". If the car has been sitting for even a short period of time and I go to move it, when I tap on the brake pedal for the first time I hear a "clunk" coming from one or more calipers. This will happen twice if I back the car up, step on the brake (clunk 1), throw it in first, drive even a few feet and step on the brake (clunk 2). After a few cycles of brake use the clunking goes away until the next time I shut the car off let it sit for a brief period of time, and then drive it.

It also seems to happen when I use the clutch, not even when I hit the brakes. This leads me to believe I have some sort of hydraulic issue. I have verified I have the correct parts (eEuroparts.com) and that they have been installed correctly with all needed clips, backing plates, retainers, fastners, etc. The brake system has been bled thoroughly, and the fluid in the system is clean and almost entirely new (DOT 3/4). The clunking did NOT happen prior to this brake job.

Is it possible that additional bleeding is required? Would I need to bleed the clutch portion of the circuit as well? Am I even on the right track?

Any input would be greatly appreciated! Again, this does not affect drivability; the brakes work perfectly in all scenarios minus what I just described (and even at that, it's just a nuisance noise at this point).

[KenLJr]

I also put new brakes all around a number of weeks back on my 2009 SS 2.0T. I just started to get a 2 stage(if you will) popping/cracking noise when coming to a med to hard stop! Can't hear it from the outside with windows down, but when you have the radio down - you can hear it inside. I get it when appling brakes and then when releasing them. Only thing i can think of is the caliper carrier on one of wheels is loose and shifts when appling brakes for the first time. Most likey it would disappear when everything heats up and expands. As far as the clutch doing the same thing i am at a lost! Ken

[Burnsside42]

Yeah my 2005 does this too - resurfaced front rotors and new pads. New springs and such up front too - I've yet to dig into it much. Sometimes it doesn't do it at all - sometimes it's all the time @ all stops. Worse in stop and go. I looked everything over and it's all tight. Could be the aftermarket pads are a little on the wrong size I think. Curious to see what you find before me.

[Finding41]

Did the slide mechanism get lubricated so it lets the caliper slide along the bolts that hold it on when the break job was done? I could see this bieng a posibility. One way to know if the caliper is sliding properly is look at the old pads. If they aren't worn evenly, IE> one pad s thinner than the other the caliper isn't sliding freely.
Another possible cause could be the spring that holds everything tight may be old and weak.
I use anti-seas on the parts of the pads that ride on the caliper assembly. (Make sure this is clean and smooth.)

[Burnsside42]

Yeah - none of that is an issue for me