no brakes Help

I just replaced the calipers, rotors and pads on my 2000 ssei and I can not get any pressure. the pedal goes to the floor after I start the car. I bleed the brakes having someone hold the pedal down half way. When the car is off and I pump the pedal it is fine but when I turn it on it goes to the floor. any ideas?

Thanks

When you bled the brakes did the master cylinder go totally empty? If it did you will have to rebleed the master cylinder in order to solve your problem. If not check the vacuum booster as it may have gone bad. If everything is fine on both of these then rebleed the brakes starting with the caliper furthest from the master cylinder then work your way around. It sounds like there may still be air in the system. Good Luck!

When you bled the brakes did the master cylinder go totally empty? If it did you will have to rebleed the master cylinder in order to solve your problem. If not check the vacuum booster as it may have gone bad. If everything is fine on both of these then rebleed the brakes starting with the caliper furthest from the master cylinder then work your way around. It sounds like there may still be air in the system. Good Luck!

Well I re bled the brakes today and still the pedal goes to the floor, whats wierd is when the car is off the pedal is good when I turn on the power its still good but when I start the car it goes right to the floor.

Do you have antilock brakes? It is possible that the computer for the brakes has gone bad. If not it may be the vacuum booster that has gone bad. It only operates when the car is running and if it has a leak it will not provide the necessary boost for the brakes. Don't have any other ideas as to what could be wrong.

Do you have antilock brakes? It is possible that the computer for the brakes has gone bad. If not it may be the vacuum booster that has gone bad. It only operates when the car is running and if it has a leak it will not provide the necessary boost for the brakes. Don't have any other ideas as to what could be wrong.


Thanks for the information, do you know where the vacuum booster is? and how to check it?

thanks again

The vacuum booster is located directly behind the master cylinder. It is the round thing the master cylinder is attached to. You may only have a vacuum hose that is loose or leaking so check that first. It is not hard to change the booster but you may want a repair manual to give you directions. There really isn't any way I know of to test one. There is a bladder inside the booster that provides vacuum pressure so that it gives you assistance in braking. If it has a hole in it the booster won't work right. It is unusual for one of these to go bad but it does happen. And since you have good brake pressure when the car is off and none when it is running I think that may be where the problem is. Once again, check the vacuum line first. It may be loose or the one way valve that attaches to the booster may have gone bad. Cheap fix if that is the case. Good Luck!