Put on my front 13" StopTech ST-40 calipers and slotted aerorotors this weekend and the Stage II upgrade on the rears with new SS lines all around. I'm using the Axis ULT pads that came with the kit for the front and some cheap Bendix pads on the rear because I got the wrong Ferodo 2500 pads for the rear and it was all AutoZone had in stock. Got everything on without issue, fitment is fine, about a finger's width of space all around on the 18" rims except for the valve stem which clears it by about 3-4mm.

So I took it around for some driving, just easing into the brakes like the install guide said, then went and did some 60-10mph threshold braking stops to bed in the pads (no full stops in between). After the 2nd or 3rd 69-10mph run I distinctly felt and heard a whump-whump-whump pulsing coming from the front right side and the person riding with me heard it as well (mechanic friend who helped install the kit). We did a few more stops to try to isolate it and it only happens occasionally. We checked it out back at his place and didn't see anything out of whack. I drove the Z into work today and on the way felt some minor vibrations during light braking but could have been my imagination.

Everything was torqued down to spec, 90ftlb on the big 22mm bolts, and 40ftlb on the 1/2" bolts on top, hand tighten + a little snug twist on the 5mm allen wrench bridge bolts. Wheel studs were torqued to 85ftlb, nothing loose when we checked it. Brakes were bled 3 full circuits around the car using Motul RBF 600 and the pedal feel is decent. Still needs some more bleeding to get it back where it was but I'll drive it around a little and try to work some bubbles out to the bleed screws to bleed.

Anyone have any ideas?

 

How did you install the front brake lines? Make sure they are not making contact with any part of your wheel. With the front end of the car up crank the wheel all the way to the left and to the right. Have your friend watch for anything funny.

 

I had the same issue. Stoptech told me it was most likely a bured edge on the slotted rotors. After a few thousand miles it went away, so that might be the same thing.

 

Yep, did that - I ran them from the caliper parallel to the bleed screw, across the strut to the factory mount point then looped it back behind the damper - same path as the stock line.

 

Could it also be that you overheated the pads beyond what was needed for break in. Were you left foot braking?

Something similar happened to me while breaking in some race pads. I had to rent the pads(hawk blues I think) that you put on the car and do some hard stops but not enough to heat up the pads too much. So all it's doing is that since those pads are so abrasive when cold, they are "sanding" down the rotor and removing hard uneven spots.

Myth 1http://www.stoptech.com/tech_info/wp_padremoval.shtml

http://www.stoptech.com/tech_info/wp...rakedisk.shtml

If you overheated the pads, you could very well have uneven pad deposits, which feels as if the rotor(s) were warped. If you didn't do too many repetitions, i don't see this being the case though.

 

Pretty certain it wasn't warped rotors/pad material but could be... Nice link to the deposit removal! Might have to give that a try - I used to warp the stock rotors all the time at the track.

BTW - I love the StopTech's. Its hard to describe but going from a single pot caliper to a 4 pot is a lot more pronounced that I ever thought it would be.