Okay, so we were going to put new rotors on my roommate's tC. We didn't actually get far, because the rotors wouldn't come off and we started to lose light. Everything got put back together and now there's no brake pressure. To stop the car from a slow speed, you have to put the pedal to the floor (which is pretty easy as there is very little back pressure).

We didn't disconnect the line, so I don't know what could be wrong here.

 

Probably have air in the lines. Did you take the pads out and push the caliper back in?

 

I took the pads out but didn't have a c-clamp big enough to push in the piston... made sure that the pads seated against the rotor after we replaced the caliper.

We're going to bleed the brakes tomorrow. Odds are, it's air. There weren't any major changes made and I was careful to not damage the brake line while the caliper was free.

 

Taking the pads out or removing the calipers will not cause air to get in the lines. If air got in the system, then it is because the system was opened up or there is a leak.

However, how many times did you try to stop it? After you finish a pad replace you need to pump the brakes once or twice to get the pedal back. This is, however, due to compressing the calipers which you said you did not have to do... but worth a shot.

 

Well, I don't know how it got in there, but there was definitely air in the lines. Bled the brakes and everything's back to normal.

If you have air in your brake lines, you're gonna have a bad time.

 

I do brakes everyday at work and there is no possible way for air to get into the brake system, unless the brake line was disconnected OR the seal around the caliper piston broke somehow...which is HIGHLY doubtful.

 

It confused the hell out of us too, all I know is that the brakes were bled and the pedal is fine now.

 

If you didnt pinch of the line good enough when taking the calipers off then you will get air into the brake line. Its no biggie, as long as you bled them properly you'll be just fine. Riding around w/ air in your line for a couple of days wont hurt anything. If you did it properly, the brakes should feel tighter then they did when the car was rolled out of the dealership.