Power Brake Booster
 

I have an unrelated car question to this forum but it could probally help some other people in case they have the problem. 94 T-Bird, With the car off I can pump the brakes and they will get really firm but as soon as I turn it on the pedal drops straight to the floor. I can stop fine but the pedal is really low. When I do stop, halfway through the motion I can feel it hit the brakes before it drops down another three inches before it actually does the hard engageing. Help!!!

Sorry, Could this be the brake booster or something else. The hoses look fine.

well, if you aren't loosing any fluid from the reservoir then your master cylinder is probably bad. Have you been losing fluid? If that's the case you'll have a lot of examining to do to find that leak. have the brakes been changed recently?

No fluid leak. Brakes and rotors were changed recently to attempt to fix this problem. The car has 124k and nothing has been changed. Could a bad master cylinder or brake booster cause the check engine light to come on?

does it have ABS? Having that fail could lead to extremely poor braking. I'd probably just take it to a brake place and tell them its between the cylinder and the booster, they'll take it from there. Brakes are just one of those things that you dont want to screw up on if you're repairing them yourself! Speaking from experience of course :D