Brakes gone after 2x15mins!

[saad]

Hey guys

Had my rotors and pads changed about 7500Km's ago, and had the bake fluid replaced with some AP Racing stuff on the 5th March.

Yesterday at the track, after 2 15 minute session where I wasn't particularly pushing it, the brakes basically went. As I was driving the car up to the starting place for the 3rd session, I noticed the pedal just went to the floor, and luckily I didn't drive into the back of anyone. I opted to pull out of that session.

Found a mechanic, and we bled the front brakes, thinking maybe it had overheated, but this is unlikely after just 2 sessions, on a high quality fluid. After 7500km the pads would have been bedded in too.

After the fluid change, the brakes weren't quite as grabby as before, so last week, I went into the garage, and had the brakes bled slightly. This did firm up the pedal nicely, but the tech said there was no air when he bled the brakes.

Today, the brakes are still shot, drivable but I have to brake earlier and push the pedal a lot further.

On the OEM rotors and pads, and with fluid that hadn't been changed in over a year, I did 2 track days, all day, with no brake fade at all.

Any ideas what may have happened?

Saad

 

[GodSquadMandrake]

Your fluid boiled buddy. It happens to me all the time too. This is just too heavy of a car with too much power and not enough brakes. You can bleed the brakes all you want but the fluid is bad so it won't make a difference until you flush it out completely. I'm trying Motul RBF 600 (Racing Brake Fluid) this time. I hear bad things about ATE Super Blue (squishy pedal, eats seals, too high of viscosity not good for ABS systems) but the Motul RBF seems to have a good reputation.

 

[saad]

the fluid is a month old and is AP racing stuff ,and this was the first track day with it.....

 

[GodSquadMandrake]

Yep I put new fluid in and boiled that day. It's not about how old it is, it's just about if it reaches the temperature of the boiling point. You can boil any fluid, even the best, if you let it hit the boiling point.
I'm just suggesting that you change the fluid and see if it corrects your problem. Not everyone drives as hard as us so they may never have boiled their fluid yet. But we both know how easy it is to do with this car.

 

[saad]

lol maybe, but if it boiled, it must be prety crap! Ill try some other fluid

 

[StreetSpeed2000]

+2 on boiled fluid. Change it, and while you're at it put in some SS lines, and switch a dedicated track pad. As soon as you get it on track with that setup, you'll hate yourself for not having done it sooner.

 

[Dynjo]

If you start to get into pad fade and keep driving, you end up using more and more pedal pressure. This drives all the temperatures way up, including fluid temperature. This is what cooks the fluid.

In this way, race pads will reduce fluid temperature.

Still need to change fluid frequently (I do it once a year) and use reasonably good stuff (it is possible to pay up to $80 per liter, but you don't need that liquid gold).

Brake fluid absorbs moisture over time, reducing its boiling point. That's why it needs to be changed -- to preserve the higher, dry boiling point.

 

[Gabriel]

Meat says that removing the dust guard helps cooling a lot.

 

[GodSquadMandrake]

Ok so remove the dust guard.
What you said about the pad fade makes sense Dynjo. I'm using Hawk HPS right now. Are the HP+ dangerous to use on the street? I like the HPS because they are so streetable but yeah every once in a while, they're not enough.

 

[GodSquadMandrake]

Ok so remove the dust guard.
What you said about the pad fade makes sense Dynjo. I'm using Hawk HPS right now. Are the HP+ dangerous to use on the street? I like the HPS because they are so streetable but yeah every once in a while, they're not enough.

 

[Dynjo]

I'm using Hawk HPS right now. Are the HP+ dangerous to use on the street? .

I've never tried them, but I've heard nothing bad regarding street or autocross. If you have them and they don't give you trouble, they sound street-safe to me.

The only knock I've heard is that they may not be enough for full-on road course work.

Hawk Blues have got to be the most widely-used race pad out there.

 

[mikeness]

During the summer months, i run HP+ all around. At the end of a 20 min session at my "home" track, I have no fade issues. BUT, the max speed is about 140-160 on this particular track (really technical, no long straights) so I would assume that if you're slowing the car from higher speeds you might have some fade issues.

As for the street, they work just fine. Either way, they have better bite than the stock pads. But, I must warn, they are loud and make a ton of dust. I simply got used to both. As a side note, I'm running goodridge SS line with Motul fluid and no dust guard. I used the ATE Super blue all season last season with stock lines, and would never suggest either lol.. big difference this season.

 

[stangg172006]

Ok so remove the dust guard.
What you said about the pad fade makes sense Dynjo. I'm using Hawk HPS right now. Are the HP+ dangerous to use on the street? I like the HPS because they are so streetable but yeah every once in a while, they're not enough.

No but they do take extra effort to stop. The peddle seems squishy when the pads are cold but once they are warm, the peddle firms up and it feels just like oem. They do squeak a lot. They do need to be at operating temps for full bite. Totally drivable as DD pads with some getting used to. :thumbsup:

 

[stangg172006]

During the summer months, i run HP+ all around. At the end of a 20 min session at my "home" track, I have no fade issues. BUT, the max speed is about 140-160 on this particular track (really technical, no long straights) so I would assume that if you're slowing the car from higher speeds you might have some fade issues.

As for the street, they work just fine. Either way, they have better bite than the stock pads. But, I must warn, they are loud and make a ton of dust. I simply got used to both. As a side note, I'm running goodridge SS line with Motul fluid and no dust guard. I used the ATE Super blue all season last season with stock lines, and would never suggest either lol.. big difference this season.

could you elaborate? You wouldnt suggest using ATE Super Blue or stock lines? or and?

 

[saad]

Im using volkswagen racing pads, so they should be good, along with AP Racing fluid that only a month old
I just dont see how it could have boiled so quickly, and it didnt seem gradual, it just seemed to happen and that was it.

Is there any way to tell from looking at the fluid if it boiled or not?