2003 Nissan 350z, standard stock brakes (stock rotors, stock brake pads, stock rubber brake lines)

-3 weeks ago, I did a full brake fluid flush, and filled with Ford Prestone Dot 3 fluid (262 boiling point DRY). After flushing the brakes, the pedal was VERY firm. Note - It was very firm with the stock rotors, stock pads, stock lines)

- I did 1 track day, about 30 HARD laps.

- Now, after the track day, I notice my brakes feel spongy again. Same sponginess as they were before I change my brake fluid

What would cause that? Did my brake fluid boil, and create air pockets? Did my fluid absorb that much moisture in the 3 weeks causing it to be spongy again? Did my dot3 prestone fluid only last 1 track day before it was garbage? Or would something else cause it? Are my pads warn causing it to be spongy (i don't think this would happen)

 

your pads wont cause it to be spongy....if you say you ran it 30 hard laps, that would be the reason. When your rubber lines warm up pretty good, (from a hard track day) they will expand when you apply your brakes....steel brake lines will solve this problem

 

your brake fluid boiled and created air bubbles which creates the soft feeling. Bleed/flush with a DOT 4 fluid ( higher boiling point) and continue driving.

 

also, maybe the pads are worn toooooo thin?

 

Thanks for the reply. But I said that befor the track day, and after the brake flush, the bakes were firm, even with the rubber lines. So, after the track day, the rubber lines won't make it spongy if they were firm before the track day. I understand rubber lines will make it spongy durng braking, but while at the track the brakes were firm. It's after that I'm talking about

 

This is what I suspected. Thanks

 

ok, so at track day it was firm....but after, it was spongy....got it. I just misunderstood. I still say get steel lines, just for better performance.

 

Flush, replace with DOT4, and bleed. Problem solved.

 

i already solved said problem phreak.....


gotta try and step in on my fame????

Don't make me step across that line now....

 

How much fluid did you need to flush your brakes?

 

Even with my BBk and ATE blue fluid i still get a little air after a trackday, every day on the track requires a bleed, just a few pumps per caliper is usually fine.