15 replies to this topic

[Tom Hampton]

I don't normally cross post from my blog, but I need a little advice :

Http://www.tomhampton.info/2011/06/brake-failure

Comments here or there are equally appreciated.

[Keith Andrews]

I don't normally cross post from my blog, but I need a little advice :

Http://www.tomhampton.info/2011/06/brake-failure

Comments here or there are equally appreciated.

I can't really see anything out of order in your pictures. I'm new this year to SM and felt a grinding in my brakes after my brake pads were past 50% wear. I thought my rotors must have gone, but when I measured them they were well within spec. They did show more wear than I was used to seeing. I checked for freedom of movement of the calipers and free spinning wheels with no issues. The grinding feel I was getting on track, went away. I did not hear anything grinding in my situation. I just ran them and they were/are fine. Not sure this will help you much....

[tony senese]

Pads and rotors look good to go to me.... seriously, if the rotor isn't cracked you have not over heated it or overcooled it.
I would drag the brakes (hard) around the paddock before the next time on track. Possibly they just were not bedded well.

[wheel]

You might also hit the rotors with a DA sander, before the next event.

[Tom Hampton]

Sorry... DA?

[Keith Novak]

Mine often sound awful when I pull it out of the garage and onto the trailer after it's been sitting for a couple weeks. It soon goes away. I chaulk it up to the tiny bits of debris embedded in the rotors.

I've found that little mom and pop machine shops will turn rotors for under $10 if you want to dress them up a touch. Brake shops usually charge more than new rotors. There should be plenty of material left. I've found that haveing them turned just a hair makes it easier installing brand new brake pads too.

[Bruce Wilson]

Nothing wrong. Racing pads grind rotors when they aren't HOT. Some brands do it more than others. Once you are in the correct temp range everything works as expected.

-bw

[Scott]

Tom - left you a note on your blog site. feel free to call me on this.

[wheel]

The dual action sander they use on body work that kind of leave little swirl marks, rather than straight marks. I use them to clean up rotors that get any kind of pad compound, or whatever, on them. Recommended by a Willwood engineer to remove one type compound before running a different compound pad.
wheel

[dstevens]

DA = dual action sander. As used in body work among other apps. I got mine at HF, under 30 bucks with coupon. I use air but they come in electric too.

Opps, looks like wheel beat me to it...

Edited by dstevens, 06-14-2011 12:12 PM.

[wheel]

DA = Duck's Ass. Common hair style of the '50s. Long on the sides, combed back into, well, a duck's ass.

wheel

[Alberto]

The rotor face looks more grooved than mine do running Hawk DTC60 pads and Centric rotors. The pad face also look a bit rough and I see some cracks in the material - didn't notice that on my Hawk DTC60 pads either. Will confirm tonight when I replace front brakes and rotors.

Were you able to get the pads up to temp during your event? I can't tell if it was a track day or race.

What were the ambient temps on the track?

Did you properly bed the pads?

How deep are those grooves in the rotor face?

Did you have any offs where sand may have gotten on the rotor face and gummed things up?

[Tom Hampton]

alberto-

It was a track day, not a race. Probably didn't get up to temp until the last session. Ambient was reasonable in the morning..but, the sun came out at lunch..and the temps reached 100 by the last session. In session 4, I was definately driving in deeper and braking harder. By the last session I was feeling pretty confident and was looking to see how late I could brake...particularly on entry to 6, 7, and 11 (ends of longest straights). Pedal, friction, and modulation were all consistent from first lap to last. No strange noises while on the track or upon return to paddock.

Yes, I followed the PFC bedding procedure.

The grooves aren't actually very deep. it was more the look of "galling" that had me concerned---The grooves that look like they were peeled.

No offs, one spin early in the day....but, I did stay on the black stuff.

I'll be sure and get a Duck's Ass Sander. thanks for the tip, Wheel!

[Alberto]

alberto-

It was a track day, not a race. Probably didn't get up to temp until the last session.

That might be the cause assuming those pics don't exaggerate what I think I'm seeing. If you didn't get them up to temps, race pads sometimes leave ugly deposits like that on the rotors. I know my Hawk HT10 pads did on my RX7.

In the past on my RX7, I have used these brake temp products to get an idea of what kind of temps the brakes were getting to.

http://www.pegasusau....asp?RecID=4974
http://www.pegasusau...roduct=THERMAX6

[dstevens]

DA = Duck's Ass. Common hair style of the '50s. Long on the sides, combed back into, well, a duck's ass.

You're showing your age or you've just watched American Graffiti. We have a pic taken about 50 years ago where my dad had a DA, white tee (Pall Mall reds rolled up in the sleeves and blue jeans, he was with my mom, a large goofy looking baby and a late 50s Chevy Biscayne. Biscayne was traded in a few years later for a station wagon when my brother was born.

[Tom Hampton]

Just a quick follow up: As everyone said, the brakes were fine. I went to the track last weekend, same pads and rotors. I drug them hard around the paddock as suggested, and all cleared up. Good all day long. Thanks.