Brake failure! please help

[FolkertSX]

well i just got out of my driveway and theres a stop sign right down my street so i went to stop and it did nothing. the pedal just sunk to the floor. so i obviously pulled the e brake and brought it back to the house. my dad and i looked for leaks in the hoses but couldnt find anything, no spots in the garage either. we filled it back up with brake fluid and in the morning almost all the fluid in the master cyclinder was gone. but none on the floor or hoses as it appears. could it be going into the brake booster. we checked the hoses coming off from it and they seemed to be clean. im so confused. i just want to drive my car again. please help. thanks to all

[FolkertSX]

[SkinnyKibbles]

How clean is your engine bay? Check your master cylinder, sometimes the dirt/oil covered parts hide the drips. Does that make sense?

[S133P3R]

also check on the inside shaft of the brake booster by the pedals' could be leaking into the car. also' try to bleed all 4 brakes to see if the lines are even getting pressure.

[FolkertSX]

How clean is your engine bay? Check your master cylinder, sometimes the dirt/oil covered parts hide the drips. Does that make sense?

uhh yea...

also check on the inside shaft of the brake booster by the pedals' could be leaking into the car. also' try to bleed all 4 brakes to see if the lines are even getting pressure.

ok ill check that tommorow. we bled the front brakes just not the back yet. do the front and back have different master cyclinders?

[PapaSmurf2k3]

Nope, its the same master cylinder...

Typically, when you bleed, you want to bleed from the farthest to the closes (start at the rear passenger side, move to the rear drivers side, then to the front passenger side, then front driver's side). You definitely have a leak somewhere if it happened overnight. Most likely your master cylinder is toast and leaking somewhere you can't see. A leak anywhere else would be dumping fluid all over the floor, or your wheels.

[S133P3R]

ok ill check that tommorow. we bled the front brakes just not the back yet. do the front and back have different master cyclinders?

well, that may be your problem right there, you are supposed to bled the brakes in order from furthest to closest in relation to the 1 master brake cylinder. the MBC is mounted on the black drum that is mounted on the firewall exactly opposite the brake pedal.

[SilviaMike]

If you have 1 bad caliper it will cause the same problem which on a S13 typically thats thats what the problem is on an S13. Jack the car up and put it on jack stands, fill the resivoir up and press the brake pedal see if one of the calipers starts dripping.

[PapaSmurf2k3]

^While busted calipers are pretty common, they usually just freeze up instead of leaking. Drum brakes usually leak when they fail (wheel cylinders), but 240s have 4 wheel disc brakes.

...it is curious how it leaked overnight with no real pressure on it. My money is still on the master.