brake peddle went soft

[rsx84]

as the title says my peddle has gone soft, i was testing the car on a private road and after two runs pulling the car up from around 180km/h the peddle went soft took around 50-70 extra meters to stop, twice as long as the frist 2 runs to pull up...

the car is a hr30 skyline, so its a bit older, still running the old single pot callipars (for now) but i'm using brand new DBA slotted rotors and B/N bendix compX pads and i have the r32 brakebooster and master cylinder installed aswell, part of the engine install...

i first throught air in one of the lines but they were bleed twice when the rotors were fitted and the peddle has stayed soft??

any ideas as to the problem??

Cheers matt.....

[predator]

you haven't split one of the lines somewhere, or one of the connections under there under the heavy braking?

[LANFOH]

sounds like a leak somewhere? What type of brake fluid are you using?

[rsx84]

thier old lines (origanal) i think, so i looked but theres no lecks or bubbles

[blind_elk]

Have you changed the brake fluid to some new stuff (you probably boiled the stuff you have)

[rsx84]

i have no idea what fluid they used? but woiuld the peddle remain soft days after though?

[Duncan]

yeah could do, it will permenantly be worse after you have given the fluid a good boiling.

I suspect something else though, maybe the master cylinder? If you hold your foot on the brake does it slowly sink to the floor?

[benm]

Sounds like you have pushed past the seals in your master cylinder... as Duncan said... if you sit idling and apply pressure to your pedal does it sink to the floor?

Take it to your local brake mechanic and get them to block the rear, then front lines and see if you can narrow it down.

[rsx84]

i'll get it to the shop i think to see what they say, hope i hav'nt damaged the master cylinder as it was put in for a r32 brake upgrade i'm doing soon!