about 2 months ago i changed all 4 rotors/pads and bleed the breaks. used ate blue, axxis ultimates, autozone blanks.

today im driving home doing 35mph and i went to stop. the peddle went all the way to the ground. i pumped it a few times and it got hard again but sinks to the floor if i hold pressure on it.

i checked for leaks around the MC, top of brake peddle, and around the caliper and didn't see anything. there is no fluid missing.

can the MC go bad without leaking? if not does anyone have a idea on what to check for? need to get this fixed asap its my only car!

 

Sounds like my car. From what I found sounds like the MC is bad, it wont leak but it is blowing by inside.

But I would like to see other answer as I am not 100% sure.

 

yea i think your right, ive owned the car for 20k miles and its @ 168k now. no idea how long ago the fluid was changed before i did it. and also i just read on here that if you push the pedal to the floor when bleeding the brakes u can break the MC.

guess its time to find a replacment.

 

My car sat for 3 years, replaced and bled everything, but I did place a piece of wood under the pedal to stop it going all the way to the floor. Mine failed a couple of hours later after a few hard brakes.

Like I said I am not 100%, so lets both wait and see what others have to say before we run out and get new MC's

Also did you do the booster tests?? to make sure the booster is not bad?

 

possible air pocket ? Or a real small leak somewhere , otherwise id say the diaphram in the MC is fucked .

 

Also check to see if the vacuum line from the brake booster to intake manifold has leaks or cracks in it.

 

sounds like MC to me

 

Yeah, an MC can go bad without leaking.It just stops converting pressure.

 

if you hold your brake pedal for a while and it begins to slowly sink, its the master cylinder for sure