The other day i was driving running some errands i was on the road pretty long prob the most driving ive done since i bought the car....im located in florida so it was pretty hot out 90 degrees...anyway i was pretty much running the car hard all day i did one last pull 2nd to 3rd got up to about 100mph then a car pulled in front of me so i hit the brakes hard no biggie the car stopped as usual after that i just cruised the rest of the way home about 5 mins from my house i notice the brake pedal felt weird it sunk futher than normal before engaging but i didnt think it was anything then i came to another stop and it went strait to the floor lol heart stop instantly..i pumped it a couple times and it went back firm...fast forward i got home reversed into my garge left it alone didnt think much of it cuase my front rotors and pads are shot from just alot hard driving,racing,top speed runs lol my rotors literally have no meat left and was going to change them out this week....mabey 40 min later i got back in the car to go somewhere brake pedal felt normal again it wasnt as firm but it didnt sink to the floor again after what happened earlier.....my question is becuase im curious did i boil my fluid or were my brakes fading and went back to normal once they cooled down which cuased the pedal to sink....

 

What you're experiencing is the Z's lesser known anti-a$$hole device which makes the driver either total the car to prevent further douche-baggery, or reality check to stop doing 100 mph pulls on city streets in 3rd gear.

 

dugan
dugan
dugan

 

3rd gear doesn't go to 100

 

Flush your brake fluid, don't stop bleeding until you see new fluid coming out. I'm guessing your fluid is getting close to black, so it should be easy to tell.

As you can see from the other comments, speeding on public roads does not impress anyone here. Save it for the track/autox.

 

Boiling the fluid creates air bubbles in the system, air can be compressed vs fluid which can not. Once bubbles get in if you press on the brake pedal it feels soft or mushy. If you press hard or long enough it can go all the way to the floor. Pumping it quickly can temporarily return some firmness. However the damage is done, the brakes might feel better after they cool down, but the air is still in there thus the problem will return quickly... and likely without any warning signs beforehand. If the rotors are too thin then they are not dissipating heat properly which is only going to make the problem worse and could be what lead to the original fading problem.

So do as recommend above: a full fluid flush and if you rotors are passed their minimum thickness replace those as well.

Just think what would have happened if the pedal went to the floor when someone was in front of you

 

OP: Reading your post makes me think of this...



And this...

 

Pedal goes to floor means air/bad fluid

Pedal stays firm and diminished braking (fade) means the pads are heated beyond their limits