2001 ITR, simple bolt-ons, gutted interior, roll bar. I removed most of the front heat shields (just left the lower portion to protect the ball joints) and the entire rear heat shields. I'm currently using stock calipers and Brembo rotors with Ferodo DS3000 pads up front and Axxis Ultimates in the rear. This setup was recommended to me by Andie Lin at Cobalt Engineering, and I have to say I was very happy with the cars braking performance at my last track day. The pedal got just a tad mushy after the first session (I'm guessing fluid related), but for the rest of the day everything stayed constant. The car felt like it was braking just fine, but I saw something a little wierd when I went to swap my street pads back on...

These are from the driver's side of the car, and the passenger's side looked pretty much the same. The inside pad is on the left, outside pad on the right.



A couple close ups of the pads.





A couple shots of the rotor.





It's pretty obvious that there is some heavy glazing on the pads, but I think the wear pattern is the real issue. The outer portion of the outside pad is glazed while the inner portion of the inside pad is glazed. Andie thought maybe the caliper bolts weren't tightened, but I'm positive they were because I needed a hammer to break them loose when I was swapping pads. I'm going to be taking some measurements of the pads tomorrow along with some more detailed photos, but I can tell you that there is no visible difference in the thickness of the pad surface (they appear to be wearing even despite the funky glazing pattern). Also, the rotor surface is even as well, and there is no surface difference between the discoloration. If anyone knows what could be causing this and if there is any way to fix it, I'd really appreciate your input.

P.S. I've been told I'm hard on the brakes, but my braking IS controlled. In other words, I'm not performing panic stops around the track. I get on the brakes when I want to slow down (usually using ABS), and then get off. There was no trail braking involved at my most recent track day.


[Modified by Bob#455, 8:47 PM 9/25/2002]

 

Hmmmm...
I thought I had destroyed pads and rotors in just about every way imaginable, but that one is a new one.

Clueless.

 

Is that about commensurate with the amount of the heat shield you've cut off?

 

Nope...the heat shield was fully removed from the top two-thirds of the rotor. So it is still solid at the bottom and wouldn't leave a ring like that...

 

Just FYI... I have the same rotors, hawk Blue pads with 6 lapping days on them. My rotor shows the same discoloration BUT!! ONLY ON THE OUSTIDE.. the inside rotor surface is normal. Also the outside pad is half shiny, as in the above picture.

These rotors and pads have not shown this until the last time I was at ThunderHill. No extreme ambient temps that day.. it was pretty much normal.

I ALSO use ducting.

 

Bob's heat shield is basically a section only to protect the lower ball joint, (kinda shaped like a slice of pie ) the rest is removed.

 

Check the "backside" of the pads and see if they're flat. It's interesting because the rotor looks like it's scored 50-50 (more on the outside obviously). Got a shot of the inside of the same rotor?

 

I will take pics of mine tomorrow. There is no PHYSICAL difference between the discolored sections.. no "raise" or surface irregularity..

 

The pads seem fine...I'll take measurements and some more detailed pics tomorrow. I'll get a shot of the inside of the rotor too.

 

gee.. thats real great input there.

 

That's pretty much not what I've heard, but the input was valuable nonetheless .

 

I would have said what Andie did. Did you check both the caliper & the braket bolts? The wear makes it look like the rotor & the pads are not parallel to each other. Let us know what you find out.

 

I'll check the bracket bolts too. Thanks.

 

yeah, somethings not lining up right. see how its glazed on the outside of one pad, and on the inside of the other pad. id be interested to see if the back side of the rotor is glazed in reverse as well, prolly is based on the pad. anyway, yeah, something not parallel.

 

Check your caliper bracket sliding pins you may have a lot of ware on them causing the caliper to tilt when braking. Are the pads backing plates fitting snug in the caliper brackets?

 

tweaked caliper bracket?

 

seems like rotor cupping to me.

 

I would go to Autozone and buy a set of $24 rotors(which I race on), and when putting them on, make sure everything is torqued to spec. See how they wear at the next event. Then take a look at them and go from there. At least that will take rotor issues out of the equation, and it would probably be the cheapest way to minimize the possible causes.

 

Are these the same rotors you use for the street? If so do your street pads exhibit sinilar wear? This 'might' be the result of swapping pads on a worn rotor, contributing to uneven pad bedding. As a general rule, trying keeping street pads and rotors together (same pair of pads with same rotor). The same applies to track pads/rotors. I hope this helps. I'd be interested in hearing what the problem ends up being.

Good luck


[Modified by rainman, 8:22 AM 9/26/2002]

 

A quick questoin then suggestion.

Did you bed in the pads? I ask because the edges are crumbling.

A suggestion: When I had my Talon on track the brake pads kept doing strange things. Wearing unevenly, wearing one and not the other etc. I finally decided that they were getting hot enough to bind in the slides in the calipers. My quick and dirty solution was to gently file down the ears on the pads to give them more room to expand and not bind. Costs nothing and no harm done if not really needed.

Good luck

Ron

 

It looks like the glazing on the inside and outside pads are exactly opposite (or was it just the reflective angle of the photo?) If the inside and outside pad wear is opposite (looks like the outside pad is glazed on the outer half and the inside pad is glazed on the inside half) then that indicates that something is tweaked in the caliper to rotor alignment. But you said the other side of the car is the same way. So how could both calipers be out of alignment??? Any non standard parts in the braking area other than rotors and pads???

The other thing that comes to mind if the outer half of both the inside and outside pads on both sides is where you are seeing the most glazing then maybe the rotors are retaining heat differently as you go from center to the outside edge. Does the wear pattern match the depth of the vents in the rotors? Maybe these rotors have a different cooling vent depth than stock and maybe these pads go closer to the inside of the rotor than stock and they are just a bad match????

Overall though, I would look at worn caliper slides as the most likely culprit. Worn/ poorly-greased slides can cause uneven wear patterns and hotspots.


Oooops - one more idea - you mentioned that you were switching back to street pads. I assume that means that you switched to your race pads before the event. Could you have contaminated the pads or rotors with some solvent brake fluid or oil either during the swap or during storage before the event??



[Modified by 00R101, 8:56 AM 9/26/2002]

 

I'm waiting for measurements and close-up pics of the rotors and pads. I have not seen this type of wear/coloration pattern before with the Ferodo DS3000. The question I forgot to ask was how many street miles were put on the DS3000's on the way back home from the track?

We'll talk more about I get the data.

-Andie

 

I too thought it was because he has been switching pads like underwear lately.

But again, I have the same discoloration, and my rotors have only seen my Hawk Blues. AND again, this discoloration only came after my last event at Thunderhill.

The ONLY difference in mine, is that the blackened section has small surface cracks.

 

Thanks for all the input guys. To answer your questions:

I use the same rotors (Brembo) for street and track, although I might be changing that soon if I still have funky pad glazing after the next event.

Yes, I bed in the pads per Andie's instructions.

The only thing I've done is change rotors and swap pads...the rest of the braking system is stock.

The pads and rotors were not contaminated with anything.

I put 300 "street" miles on the way home, but that includes 250 miles on the interstate where I did not have to use my brakes. There was definitely less than 50 street miles on the pads.

I just took pad measurements and some pics of Chris' pads so I'll upload them soon. Thanks again for all the input. I'm going to double check all of the caliper and bracket bolts and grease the caliper slides to see if that changes anything at the next event on Wednesday.

 

Here are pictures of the inside of the rotor. Sorry they aren't that well lit, but it looks like the inside does not have the severe color contrast that the outside does.





Also, I measured the pads and they seem to be quite even (or are they supposed to be absolutely perfect?). Please refer to the photo below for the measurements. The inside pad is on the left and the outside pad is on the right. All measurements were taken from the base of the pad to the edge of the pad (only the pad was measured, not the backing material) and are given in 32nds of an inch. Ie., 12.5 = 12.5/32" Thanks again for your help.




[Modified by Bob#455, 6:59 PM 9/26/2002]