dpine

I know its been about a month since Expo 11 but I would like to share my braking issues I had at Expo and see if anyone can give me some insight on what could have happened. I will try to be as detailed as possible. I will say this was my first track event and my braking could be suspect as well.

So to start off My ITR has 65K on the origional rotors and pads (pads still had 50%) so braking wise the car had not really been pushed however that may or may not mean anything.

A week before Expo I changed out the brake fuid with ATE type 200 (via a automated brake bleeding system), replaced the pads with Hawk HP + front and rear, and swapped out the rotors front and rear with autozone blanks (cheapies).

Afterwards I followed Hawks bed in procedure.

Fast forward a week. I put 500 miles (highway) on the brake system traveling to CMP.

On the first session out everything was fine. The car stopped great. Once off track I drove around the pits and then parked making sure to not use my parking brakes.

On the second session out about halfway though I started to feel vibration under medium/hard braking. It was pretty bad towards the end of the session. I again I pitted, drive around, and then parked.

At this point I asked my instrustor Don (He's a heck of an instructor!) what he thought. He thought it would be a good idea to take a look under the front suspension, brakes, and wheel bearing.

So I jacked up the car and inspected everything. All the bushings were tight, the ball joints were tight and not torn, The brakes looked ok except for some discoloration around the rotor hat. There was also no vibration/looseness from the wheel bearing.

So we went out for the 3rd session and the exact smae thing happened (vibration/warped rotor feeling halfway through the session).

At this point the session ended and I decided that I didn't have an answer for the brakes that it would be a good idea to pack it in and not potentially cause injury to me, my instructor, or others on track.


After we left the banquit that night I drove back to the hotel and on the way back I did some 70-0 hard braking and could never get the front end to shake. I had no issue on the way home to VA and I havn't had any issues driving it since. I know I will want to do more track events in the future and I have a feeling this will come up again.

Also something else I for got to mention that could have been a factor. I didn't realize until after wards that my tires I was running (Fusion zr )were quite a few years older than I thought (5 years). They had quite a few spots where either rubber moved around on the tread or was picked up on track that would look look kinda like deposits on a drag slicks

So with all that said was it warped rotors, tires, my braking, pads?

I am all ears for anyones insight/thories. thanks

Egezzy

iTrader: (2)

from what you have given it sounds like it was from the tires once they got hot.

dpine

Can you elaborate more on the subject.

chrisb

Did you let Don drive it a couple of laps? If not, did Don feel an obvious front end shake from the passenger seat under braking or was it more subtle than that? I always bring spare rotors to the track. Inevitably as you keep doing this stuff you bring more and more **** and wish you had brought more **** still. You were torquing your lug nuts after every session right? Did you try swapping your front tires to the rear to see if the issue resolved? Don't be afraid to ask around for help or advice when you are at the track. I was there instructing in the red/silver Integra parked next to Jonathan Baker. We could have helped you diagnose the issue or at least try. Track guys will generally do most anything to help you with issues and then you can hopefully solve the problem and get all the track time that you spent hard earned money on. Just an FYI for next time.

I bought a dial indicator and magnetic base a while back and it helped me find an issue with vibration under braking. I used it to check runout on all of my hubs and then the hub/rotor assembly. It is hard to say what it might be as there are so many variables. That is why diagnosing at the track is the best route IMO if you are already there anyway.

dpine

Ok,
1)No I didn't ask or let Don drive the car
2)I am not sure if he did feel it. However visually he could see it (steering wheel, and shift lever shaking violently)

3)Yes I torqued my lugnut before I went out on track (every time) and checked tire preasure as well. I didn't bring spare rotors either.


4)I didn't swap tires. I wish I had. Unfortunatly it was my first Expo as well so I kinda got off track since there was stuff going on through out the day. I was reluctent to ask people I didn't know, which was everyone.

Egezzy

iTrader: (2)

given you drove home and are still driving on the "setup" you had at expo without problems then it leads towards one thing. you tried simulating your braking while going to the hotel(tires "cold") and didn't experience any vibration. you drove all the way home and didn't experience anything else. so i'm guessing it was build up on the hot tires. i have went to get gas in the morning in the past on a higher treadwear tire with marbles on it. i had a slight vibration but it almost went away fully on the drive back from the station.

chrisb

No worries. It is all a learning experience. And those weekends are pretty hectic. I had two students and my session so I only had one session in which to gas up, torque wheels, hydrate, check oil etc. I just waited until Saturday night to rotate tires as there was no time during the day. It is tough to work on a student's car too. But I hate to hear that someone packed it in early when we could have tried some things that Saturday night or maybe given some advise for things you could try on your own.

Beer, snacks, water, sodas etc. are great tools for meeting people and getting advise. In 2002 I ran the NASA comp school and handed out some beers to racers I met. A month later those same racers (Jack Harris and others) dropped everything they were doing and jacked my car up to swap a corded front left tire to the right rear 5 minutes before we had to be on grid for the race. They probably would have done it anyway but a little good will never hurts. I am a pretty shy dude normally but most track guys I have met will do anything they can to see you on track. Hell, another race a competitor sold me a clutch after mine grenaded and I summarily went out and beat him with it. That is how it is. Good camaraderie among car guys.

Drive 4 fun

I had this happen with HP+ on NSX calipers and rotors. I had the HD rotors from Fastbrakes so lost of mass to counter heat. Turned out to repeatedly happen after the first session. I drove the pads on the street also, and the problem never occurred on the street. After the car cooled and I drove it, no problem. Think pad deposits on the rotors. For me it was resolved with track pads that operated at higher temps and did not deposit. Spoke with Brian at Fastbrakes who agreed.

dpine

Yeah, I kinda wish I had more time to met people at expo. It's funny , Don ended up meeting me right as I was in line to go out on track and the whole time he had parked next to me that morning.

At this point it seems it was caused by tires or pads. The person that posted above spoke about uneven pad material across the rotors which seems logical

92integraVTECgsr

Do you still run the factory brake rotor heat shields?

If so, I would suggest taking those off.

Next time, bring at least one extra set of rotors. I would avoid autozone rotors as they stack them sideways instead of flat which can cause them to warp (I know, I've bought several sets from them and they were warped right out of the box).

I now use Beck Arnley premium rotors, but Advance, O'rielly's or NAPA are good places to get rotors. O'Rielly's probably the best because they turn their rotors for free if you have an issue.

And yes, ALWAYS ask track guys. Never hesitate to ask for help. We are all there to have fun and meet new people.

rice_classic

I know exactly what it is.

Uneven pad deposits. How they developed is what you need to discover to fix your problem. Here's some ideas:

1: Even with proper burnishing procedures, pads can move below or above their optimal heat range during your time on track which can cause the pad to develop an uneven deposit. Sometimes, it just happens but you can BRING THE BACK during the session.

From StopTech:
1a: Take some 300 sandpaper and scuff the transfer layer off your rotor and re-bed the pads. Or, have them turned then re-bed them.


2: When you parked the car, the caliper/rotor/pad are still very hot and letting your car sit in one place like that probably allowed the pad to put extra material (even thousands of an inch) on that part of the rotor. This will cause vibration under braking as the transfer layer is now uneven... See 1a

2a: I've heard for many years in the paddock that 9 out of 10 rotors are warped in the paddock... not true. I'd say 9 out of 10 rotors receive an uneven transfer layer after parking in the paddock after a session. After you park your car, wait 3 minutes and roll it backwards a bit, then after another 5 min, do it again. Or, on your cool down lap use your brakes less.

3: You want to know more? Read this, watch this:

http://www.stoptech.com/tech_info/wp_bedintheory.shtml
and don't forget to read the FAQ's

Watch this:
http://www.essexparts.com/learning-c...rs/post/Bed-in

VTECIntegra9

Awesome responses - just wanted to point that out. And I agree with ChrisB in every way - anyone will help you out any day, even if we don't really like you! (j/k)...

Only people who don't get help are the ones that are driving over their heads, cocky, inconsiderate, and otherwise conducting ***-hattery... we crack a beer, watch them fix their busted car, and enjoy the evening.

You're not one of them and if you're new you need all the help you can get. Don't take that the wrong way either. The most problematic thing I've seen in the events i've instructed - the students being very nervous about their car on track (understandable!), overwhelmed with the activites, rituals between sessions to ensure a safe drive, and taking it all in... it just becomes too much. And on top of that I'm instructing them 100 different things that they havn't experienced before and expected to remember every hour.

Come out to more events and make sure to see if any HT (or other guys who may not be on HT often but fall into the expo-type crowd) are coming and pit nearby and enjoy!

dpine

I can agree that I was nervous on track. Back years ago when I use to go to drag racing events I always trailered my car. I didn't trailer it to expo which but some stress on me because I really didn't want to have something happen and get into a situation where I had to get the car back to VA. I know tons of people dont trailer their cars to events so I decided to not as well. Yeah there was a few things I learned off track about this hobby.

Anyways back to why I stated this thread.

I am going to pull the wheels, calipers, pads off this weekend and inspect them. I will post up pics for people to chime in.

Drive 4 fun

My deposits stopped when I went to track pads. My deposits also took care of themselves with street driving, only to return at the track. I did not sand them off, they wore off. I think it is from pads at the limits of their heat range. Removing dust shields could help. Once they were back to feeling normal, they looked normal.

dpine

Well the factory dust shields are still on. Your the 3rd person to tell me to get rid of them so while I have everything off this weekend Ill take them off to. I actually liked the HP+'s but I would have never thought they would have done that however I know squat about brake pads. I was told by members on here and ITRCA that they were a good beginers pad

chad

you may have a bad wheel bearing that only does that once pushed on the track with hard turns and braking....70-0 on the street in a straight line might now show this!

dpine

Chad, other than checking by force (moving the wheel/hub around while front end jacked up in the air)for play. What other way would I check the wheel bearing for fault?

VTECIntegra9

See if it is running at a higher temperature than the other side with an infared pyrometer. This is one of the most useful tools evar!

mrlegoman

It felt like a warped rotor. But was strange that it was progressively worse through the session. I only remember the vibration under braking. I figured that if it was a tires issue, there would be a similar vibration under acceleration too.

I wished you would have come back Sunday. I would have had you try a short-shift before going into 3 and I thought about trying a smoother line around 12-13. All in all, you handled the car very well. There where a couple things I wanted to point out to you, pop me an IM if interested.

It's going to be frustrating trying to hunt down the problem if it only surfaces on the track.

dpine

Thanks Don, I will IM you when I get back (im away in trainig class this week)
I didn't get a chance to look at the cars brakes last weekend. I'm hoping to get a chance this weekend. I havn't driven the car in 3 weeks and have had more important things going on. You guys know how that is.