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Discussion Starter #1
Yep, so first track event, im on stock pads and rotors, i swapped to a valvoline dot 4 synthetic brake fluid, after the first 20 min session, its boiled.


im going to upgrade pads and fluid. recommendations?
 

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Yep, so first track event, im on stock pads and rotors, i swapped to a valvoline dot 4 synthetic brake fluid, after the first 20 min session, its boiled.
im going to upgrade pads and fluid. recommendations?
[/b]

Are you sure you were boiling fluid? A spongy pedal is usually the first sign of that, and even after it cools down the pedal will still be mushy.

Pads can "fade" also, when that happens you still have a firm pedal but the car just won't stop. That will get better if you take it easy on the brakes for a little while and let the pads cool back down.

I'm not real familar with the Valvoline fluid but it appears to have a 500 degree dry boiling point. You can find some better fluids like Motul but they get pretty expensive. I assume you did a entire flush of the system when you put the Valvoline stuff in?

Ducting some air to the front brakes might be a consideration. Ideally you want to aim it right into the center of the back of the rotor so that it flows outward thru the vanes, sometimes with stock dust shields and all the hardware that's hard to accomplish but it will give you the best cooling of the whole brake assembly.
 

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Need track pads up front for the track.

Unlike other race pads, Porterfield R4 ($$) can be installed at home and driven back and forth to track, with no issues. Sand rotors when switching race and street pads.

Try the new suspension?
 

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Need track pads up front for the track.

Unlike other race pads, Porterfield R4 ($$) can be installed at home and driven back and forth to track, with no issues. Sand rotors when switching race and street pads.

Try the new suspension?
[/b]
I'm not a great fan of those practices. "Track" or "Race" pads are usually very poor performers in street driving applications. Yes, you CAN do it, but that doesn't make it a wise idea.

If you sand the rotors you better be prepared to bed the new pads in again, you're removing the friction material the pads deposit on the rotors which is part of the braking process.

Better off to get a good "performance" set of pads, good fluid, and try blowing some air in there first.
 

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Discussion Starter #5
new suspension is not here yet.

the symptoms were a very very spongy pedal ( able to push to floor) but after repeated pumps it would be kinda firm for like a half second before giving in again.


ive looked all over the car for leaks, watched the fluid for dropage... nothing..


i just swapped the fluid again, and i still have the same problem. i bled them in the proper fashon, swapped back to the same fluid ( i had an extra bottle).


friend of mine says air can build up in the ABS system, causing this feeling to happen even if the brakes are bled. he says youve gotta hit abs a couple times to get the air into the system, then rebleed after a few days.


any other suggestions?

i dont want to be swapping pads if i dont have to before each track event, i'd like a pad that can be streeted in michigan winter, but still make it to the track. if that means hps's ( if hps are any good for the track) then ill do that, if you have a better recommendation, or if your recommendation is that i get track pads and switch them still, i might do that up front.

what do you think kev?

perhaps some hp+ up front with hps in the rear?


ebc yellowstuff R? do they make that for our application?

i want an agressive pad, i dont care about dust, i care a bit about noise, i care alot about making my brakes work again. and much better than they did before.
 

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new suspension is not here yet.

the symptoms were a very very spongy pedal ( able to push to floor) but after repeated pumps it would be kinda firm for like a half second before giving in again.
ive looked all over the car for leaks, watched the fluid for dropage... nothing..
i just swapped the fluid again, and i still have the same problem. i bled them in the proper fashon, swapped back to the same fluid ( i had an extra bottle).
friend of mine says air can build up in the ABS system, causing this feeling to happen even if the brakes are bled. he says youve gotta hit abs a couple times to get the air into the system, then rebleed after a few days.
any other suggestions?

i dont want to be swapping pads if i dont have to before each track event, i'd like a pad that can be streeted in michigan winter, but still make it to the track. if that means hps's ( if hps are any good for the track) then ill do that, if you have a better recommendation, or if your recommendation is that i get track pads and switch them still, i might do that up front.

what do you think kev?

perhaps some hp+ up front with hps in the rear?
ebc yellowstuff R? do they make that for our application?

i want an agressive pad, i dont care about dust, i care a bit about noise, i care alot about making my brakes work again. and much better than they did before.
[/b]

well spongy pedal that gets a little better when you pump it sounds like the fluid is boiling.

I'm also assuming that at the start of your session the pedal is firm and consistent, but goes to shit when you start beating on the brakes hard.?

I know some cars have different ABS bleeding procedures, but if you're starting out with a firm pedal that gets spongy after you use the brakes hard I don't think the ABS is the culprit, nor is it "letting air into the system". Besides, if you're boiling fluid you're doing it at the calipers, not up at the ABS controller.
Do you try bleeding the brakes after coming in off the track? Do you get air bubbles and discolored fluid? That would be a sure sign of boiling.
Unfortunately I don't think pad changes are going to help this problem. Getting some cooling air in there somehow would seem to be a better solution, and maybe a better fluid.
 

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Discussion Starter #7
it seems to me that ( after reflushing the system fully again, and bleeding again a few days later ( all without air bubbles) that i really didnt boil the fluid.


i believe i overheated the pads and cooked them. making them less responsive to brake pressure, requiring me to apply more pressure for an equal braking force.


basically, stock pads should not be allowed on the track. i reallly really cooked mine ( will know when i swap pads) but it makes sense. the car is getting better over time, back to normal. wearing away the part that i cooked.

my rotors show thermal discoloration, i really did get them hot.


in this case then, pads would help.
 

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it seems to me that ( after reflushing the system fully again, and bleeding again a few days later ( all without air bubbles) that i really didnt boil the fluid.
i believe i overheated the pads and cooked them. making them less responsive to brake pressure, requiring me to apply more pressure for an equal braking force.
basically, stock pads should not be allowed on the track. i reallly really cooked mine ( will know when i swap pads) but it makes sense. the car is getting better over time, back to normal. wearing away the part that i cooked.

my rotors show thermal discoloration, i really did get them hot.
in this case then, pads would help.
[/b]

Well, if this helps any, here are some highlights from the Stop-Tech people. Note in particular the first paragraph of "Myth #3"

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From the tech article on brake system upgrades, the entire article is readable here:

http://www.stoptech.com/tech_info/wp_brake...elections.shtml


BRAKE FADE

Repeated heavy use of the brakes may lead to "brake fade". There are two distinct varieties of brake fade:

1) Pad fade: When the temperature at the interface between the pad and the disc exceeds the thermal capacity of the pad, the pad loses friction capability due partly to out gassing of the binding agents in the pad compound. Pad fade is also due to one of the mechanism of energy conversion that takes place in the pad. In most cases it involves the instantaneous solidification of the pad and disc materials together - followed immediately by the breaking of bonds that releases energy in the form of heat. This cycle has a relatively wide operating temperature range. If the operating temperature exceeds this range, the mechanism begins to fail. The brake pedal remains firm and solid but the car won't stop. The first indication is a distinctive and unpleasant smell that should serve as a warning to back off.

2) Fluid boiling: When the fluid boils in the calipers, gas bubbles are formed. Since gasses are compressible, the brake pedal becomes soft and "mushy" and pedal travel increases. You can probably still stop the car by pumping the pedal but efficient modulation is gone. This is a gradual process with lots of warning.

In either case temporary relief can be achieved by heeding the warning signs and letting things cool down by not using the brakes so hard. In fact, a desirable feature of a good pad material formula is fast fade recovery. Overheated fluid should be replaced at the first opportunity. Pads that have faded severely should be checked to make sure that they have not glazed and the discs should be checked for material transfer. The easy permanent cures, in order of cost, are to upgrade the brake fluid, to upgrade the pads, or to increase airflow to the system (including the calipers). In marginal cases one of these or some combination is often all that is required.


----------------------------------------
And from the tech article on brake system myths, the entire article is readable here:

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml



MYTH # 3 - A SOFT BRAKE PEDAL IS THE RESULT OF PAD FADE

The all too familiar mushy brake pedal is caused by overheated brake fluid, not overheated pads. Repeated heavy use of the brakes may lead to "brake fade". There are two distinct varieties of brake fade

A) When the temperature at the interface between the pad and the rotor exceeds the thermal capacity of the pad, the pad loses friction capability due largely to out gassing of the binding agents in the pad compound. The brake pedal remains firm and solid but the car will not stop. The first indication is a distinctive and unpleasant smell which should serve as a warning to back off,

B) When the fluid boils in the calipers air bubbles are formed. Since air is compressible, the brake pedal becomes soft and "mushy" and pedal travel increases. You can probably still stop the car by pumping the pedal but efficient modulation is gone. This is a gradual process with lots of warning.


MYTH # 4 - BOILED BRAKE FLUID WILL BE SERVICABLE AFTER IT COOLS.

Once the brake fluid inside the caliper has boiled, it has lost a significant percentage of its original boiling point and should be replaced. It is not necessary to remove all of the fluid in the system, just bleed until clear fluid appears.
 

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Discussion Starter #9
good stuff, thanks. just a reminder tho, all of the fluid talk ive already done, swapped it out fully and bled it twice. daily driving wont boil my flui

i believe the pedal is firm, ( when moving, when stopped, its not as much, kinda wierd) its just that i need to push the pedal farther ( because ive overheated the pad) to get an equal stopping power.

one of the techs i know looked over the car and said that it possibly could be the brake booster. the valveas could be stuck in the wrong direction, making braking easier.


if pads wont help, im gonna bring it into service.
 

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good stuff, thanks. just a reminder tho, all of the fluid talk ive already done, swapped it out fully and bled it twice. daily driving wont boil my flui

i believe the pedal is firm, ( when moving, when stopped, its not as much, kinda wierd) its just that i need to push the pedal farther ( because ive overheated the pad) to get an equal stopping power.

one of the techs i know looked over the car and said that it possibly could be the brake booster. the valveas could be stuck in the wrong direction, making braking easier.
if pads wont help, im gonna bring it into service.
[/b]

i'm a bit confused:

You're having this problem at track events or during regular street driving?
I was under the impression this discussion was related to your on-track activity with the car.
As the tech articles mention, if you've got a mushy pedal its a fluid issue, if the pedal is firm but ineffective you've got an overheated pad issue.
I'm not sure the brake booster really plays a part in this, it only uses vacumn to assist in the pedal effort, if it were failing you would simply notice a large increase in pedal effort, but the car would still stop.
 

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Discussion Starter #11
alright, the problems occured after my first 20 min session on the track. long pedal travel, not enough braking. all the way home.

i flushed the system again ( this is all after the event, in an attempt to correct the problem)


the brake pedal will still hit the floor when the car is on and im stopped if i push hard enough.

while driving, the pedal has been feeing increasingly better, but the feeling is not like ive hit the brakes, it is still mushy a bit.


now, hydraluic systems shouldnt feel mushy at all, just hit a point and hold, with the only variable being the force i apply to the incompressible fluid, not the pedal moving.
the feedback of the brakes isnt really back yet.


i can still hit ABS and brake to full, however, with one pedal stroke from 50-60 down to 5 or so.


basically:

Symptoms on track:
Longer brake travel
Less braking


Symptoms after the track: ( and after another fluid swap)

longer pedal travel, (not nearly as bad as when on the track, but its also getting better)
less braking ( but seems to be getting better)

im not losing fluid so i shouldnt have any leaks.

any other ideas or should i have the dealership check out my entire braking system?
 

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I think you may have glazed your pads and rotors, I would recommend removing the pads, and inspecting them, if they are really shiny then sand them down, and sand the rotor down as well. Reinstall everything and give it a try. Swaping the pads on the car are very easy, and can easily be done when changing tires at the track. I would recommend having another set of rotors for the track pads, just stock blanks would be more than enough, but you should try and avoid mixing the two compounds on the same rotor.

I have the SS lines, RBF600, and Carbotech pads with Rotora blanks. Having another set of pads with rotors will be the next best thing for me, and is the best upgrade short of a BBK. I"m also looking into getting the Titanium Pad backing plates which has been shown to reduce the heat transfer from the pads to the caliper.
 

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alright, the problems occured after my first 20 min session on the track. long pedal travel, not enough braking. all the way home.

i flushed the system again ( this is all after the event, in an attempt to correct the problem)
the brake pedal will still hit the floor when the car is on and im stopped if i push hard enough.

while driving, the pedal has been feeing increasingly better, but the feeling is not like ive hit the brakes, it is still mushy a bit.
now, hydraluic systems shouldnt feel mushy at all, just hit a point and hold, with the only variable being the force i apply to the incompressible fluid, not the pedal moving.
the feedback of the brakes isnt really back yet.
i can still hit ABS and brake to full, however, with one pedal stroke from 50-60 down to 5 or so.
basically:

Symptoms on track:
Longer brake travel
Less braking
Symptoms after the track: ( and after another fluid swap)

longer pedal travel, (not nearly as bad as when on the track, but its also getting better)
less braking ( but seems to be getting better)

im not losing fluid so i shouldnt have any leaks.

any other ideas or should i have the dealership check out my entire braking system?
[/b]

i'm assuming by "flushing" you're doing a complete system bleed, and not seeing any air bubbles when you're done?
was the fluid discolored after the track session? thats a pretty good sign you got it way too hot.

"mushy" still indicates a hydraulic issue, glazed pads or rotors would still give you good pedal travel andno sponginess, but the car simply wouldn't stop very well. It would require a lot more pedal *effort*, not travel.

unless somehow you've gotten some air somewhere the ABS unit, but I dont see how.

how is your pad thickness? if they're all worn pretty well down that would give you a bit more pedal travel.
 

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Superblue ATE brake fluid FTW!!
 

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How did you bleed the brakes? Pressure bleeder, vacuum bleeder, standard pump the pedal routine? The reason I ask is that I recently heard that you shouldn't use a vacuum bleeder on an ABS car because it can draw air into the system. Don't understand how, though.

Also, I definitely wouldn't use HPS's on the track. Did my first track day in my Miata a month or so back and, in my inexperienced hands, the HPS's weren't really up to the task in a car that is ~1000 lbs lighter than a 6. I got pad fade on the 2nd day after ~15 minutes of running in 20-25 minute sessions(it rained all day on day 1 - didn't tax the brakes much). I'm currently in the process of upgrading the brakes with the larger ones from a later model and at the *minimum* switching to HP+'s. Still debating on dedicated track pads, though.

My experience with the pad fade was that it took more and more pressure to slow the car, but the pedal never got soft. I was running ATE blue, BTW. Don't know if you had a ride-along instructor or not, but mine told me at least part (if not most) of my problem was braking too early and too long, building up heat in the pads that didn't have time to dissipate. Following his instructions and braking harder at a later time, I was able to diminish the fade noticably.

Sorry I can't really address your on-going brake problem, though . . .
 

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it seems to me that ( after reflushing the system fully again, and bleeding again a few days later ( all without air bubbles) that i really didnt boil the fluid.
i believe i overheated the pads and cooked them. making them less responsive to brake pressure, requiring me to apply more pressure for an equal braking force.
basically, stock pads should not be allowed on the track. i reallly really cooked mine ( will know when i swap pads) but it makes sense. the car is getting better over time, back to normal. wearing away the part that i cooked.

my rotors show thermal discoloration, i really did get them hot.
in this case then, pads would help.
[/b]
bingo.

Track front pads, esp if you get spare rims and r-rubber, need to take extreme heat (1200F), and usually will not be a good winter pad. I think Crossbow used carbotech race pads. I used porterfield R4S as street pads (93rx7) and R4 race pads up front for track day. Had no problem with switch, likely by staying with same brand and general type of composition.

Routine for me is/was before track day, car on jacks:
-new oil (higher visc)
-race pads up front .. hand sand rotors (keep track of pad locations)
-bleed brakes (ate)
-inspect suspension, snug any coolant (or intercooler) hose clamps.
-race tires/wheels

The better you get, the more you need those front race pads for track day. I've seen my bud turn metalmasters up front into flames on an awd talon, braking hard from 125 mph for 40 mph corner.
 

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Superblue ATE brake fluid FTW!!
[/b]

Yikes! Don't do that.

I don't post here much, but will offer that you can pm me if you want. I ran showroom stock for about 15 years, so I know what you're going through with the boiling.

Number one. Get Motul 600. It's just under 600 boiling point (compared to 535 for supercrap blue). If you must use super blue, go to your local Ford dealer and get some Ford HD fluid at about the same temp for amost no cost. The Motul is widely available and relatively inexpensive. I use Wilwood exp600 which has a 635 boiling point (dry) usually. My racecar currently has Motul in it and has done fine.

I did research about 2 years ago and posted on www.nasioc.com in the new england section under the title "brake fluid thread". I had also fallen into the super blue trap until I did the research.

If you are NOT running in a time trial series or other racing series (like autocross) that would prohibit it, remove your backing plates. This is an easy way to get air to the rotors a bit more. The next step in this is to route brake ducts, but I find that this takes an entire season of trial and error to have a good working system that doesn't need to be adjusted all the time.

When you do the fluid, You can bleed the M/C all by itself first. I had a friend with an RX8 who needed to do this during a track day. After that, go one caliper at a time and the old fashioned way of friend pushing the pedal and you releasing the valve works fine. Route the line from the caliper up and then into a catch container. This way, if there's any mistake by your friend in letting go of the pedal, there's fluid in the line that can go back in...instead of air.

I believe the fluid should do the job alone as M6's have very good brakes (I've taken mine on the track when the racecar broke one weekend just to get some seat time).

As for pads, there are great track pads out there, but with a street driven car, you sort of have 2 choices. Either have a set of track only pads that you swap out for track days only or get a compromise pad. Carbotech would be best for pure track. Call them directly. They have tech guys who are great. Tell them what you're doing and they'll recommend the right pad for you. They're not cheap, but work well. (I have no connection to them....I'm an electrical engineer).

Back in my showroom stock days, I would run temporary ducts tie wrapped under the car and getting air from below the spoiler. Use cheap tubing like shop vac hose or something similar as you're probably going to only get a day out of them before they get pretty scraped up from hitting the road occationally. Duct tape is your friend. I would then cut them off before the races. I'd have good fluid and still be legal.

Other potential street pads are performance friction. Autozone sells them with a 2 year wearout warantee. You'll overpay up front, but if you do a lot of track and street driving, you'll make it up with replacements. I would get new pads 3 times a year without complaint from them.

jack
 

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Discussion Starter #18
i like performance friction alot.

i guess what i should go for, is a good compromise pad, perhaps somthing along the lines of a hawk hp+ if not a little stronger, then get some race pads for the front for track days.


btw, i looked at one of the pads up front today. parts of the pad were pinkish, and the pads were shiny on the trailing half.
looked pretty beaten up to me. friend commented that he had never seen a pad that was not consistant in color in the material. i must have done somthing.


btw, i know how to brake properly, thats the main reason why i think i got so much heat into the brakes. i can hit threshold really quick and hold it there. i should take some pics of the pads and rotors when i get the new ones. im going to call up raceshopper and see what they think i should go with.


btw, if i was going with a new fluid i would definatley go motul. superblue isnt much of an increase from what i have now.
 

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Arch,

I run Carbotech Panther+ (front) and Bobcat (rear). This is what Carbotech reccommended. I did a track event at Blackhawk in August and they held-up very well. In fact, the PCA instructor took a few laps with my car and remarked how well it braked and handled. In fact, anyone who's driven my 6 loved its brakes.

The downside with the Panther+ is the dust. After 3 days of street driving, my front wheels look like I haven't cleaned them in over a week. For the Winter, I'm going to switch back to my Hawk HPS pads.
 

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.... If you are NOT running in a time trial series or other racing series (like autocross) that would prohibit it, remove your backing plates. This is an easy way to get air to the rotors a bit more.
jack
[/b]
I did this on the rx7 ..... very effective. Jack has good advise based on experience.
 
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