You have a leak in the brake system, need to check the medal brake lines that run through the frame rail and goes to the back wheels, It is common for those to rust into towards the back. If lines are okay then check the wheel cylinders. If you are not low on brake fluid then you probley have a bad master cylinder.
try and bleed brakes , if that wont work you need a master cylander
Caliper slides frozen? Rear drum brakes? May need to be adjusted
Sounds like a bad booster. If you can't pump up the brakes to get a firm pedal while engine on, you might want to have it checked. If they're ABS brakes and you hold the pedal firmly, it should feel like they're pulsating but the pedal shouldn't just go to the floor. Could be the master cylinder.
The best way to tell when you need brakes is by squeaking, when the brakes are rubbing against the metal, when your brake pedal goes all the way to the floor and when you are running out of break fluid.
ouch,are brakes adjusted correctly/ sit in vehical and pump pedal to get a full pedal,then hold pedal to see if it bleeds off and goes to floor,if it stays, replace shoes and pads if it goes to floor, there is a fluid leak somewhere is there brake fluid in the resevoir/ are there any brake fluid leaks ,check backside of wheels there is a brake fluid pump, on the chassis rail about level with the front of the front door on the left side.if this pump is bad your pedal will go to the floor
Check the caliper slides (may be frozen) should slide freely to compensate for brake pad wear
You need to bleed the brakes.
well that is a warning sighn they do to let you know your brakes are getting down there meaning time to get new ones I dont agree with that if it were the brakes then you would here it when you apply the brakes. If you hear it when you are on the gas then it could be the cv-shaft. If it is then it could cost you around 200 - 350 dollars.
Could be low brake fluid or just worn brakes in need of replacement. Could also be a faulty master cylinder.
Ensure that the wheel speed sensor/ABS sensor has been re installed properly at the wheels. Re-bleed brakes starting from the rear and then finish with the drivers side front.
try pumping up the brakes and see if that will give you a harder or higher pedal. sounds to me like you need to have the brakes bled properly to remove air from the system
If sitting still in your car with the engine running you can apply the brakes and the pedal slowly goes towards the floor you have a defective brake master cylinder. The only repair is to replace the master cylinder. This is a very dangerous situation and must be repaired immediately. Failure to replace the master cylinder may result in an accident.