I had a question about changing my brakes for my 92 Maxima SE. I changed my front brake pads on my car, making sure to unscrew the brake line to let the air out. I replaced the brake fluid that leaked out. My problem is that when the car is turned off, I pump the brake pedal and get the pressure that usually happens, but when I turn on the car, there is no pressure on the pedal at all. I tried pumping the brakes to get pressure, but nothing happened. I pulled opened the brake line off and made sure fluid was going through, and it was. I have no idea what could be wrong with it. If anybody has any idea, anything would be helpful at this point.

Are you sure some air didn't get into the brake lines when you were doing the lines? What method did you use to drain the fluid and replace it?

You don't have to remove or unscrew any brake line connections when you're just changing brake pads. Now it sounds like you have alot of air in the system. You need to the air out of the brake line.

i did this by accident on my brother's accord one time. if you let fluid out by accident air gets into the system. you have to bleed your brakes now since you probably have air in your system, as previously stated. goodluck

How do I bleed my brakes, I've never done it before.

Get yourself a service manual and a "helper" and bleed the brakes. You never just remove the brake lines and then reattach them without bleeding the system. This will get you air in the system as everyone esle so far has stated. It will give you that spongy pedal feel. The moisture in the air will also lower the boiling point of the fluid that is there and if there was too much moisture could possibly cause the lines to develop rust (this would be quite an extreme).

When the car is on the brakes get some vacuum assist. This is why they were fine without the engine running, but went to the floor with the engine running. I always go around them a second time with the car running just to make sure.

DO NOT DO THIS IF YOU HAVE ABS! I suppose if unplugged it SHOULDN'T have any effect on it but who knows?

Fortunately, I don't, but I didn't know this. Works great for my non-ABS car. I have the braided lines and the pedal gets rock-hard.

Don't take this as an insult, but it sounds like you are not sure of what you are doing. Your brake is the only thing that keeps you from hitting the other car. I am not the type to let others fix my car, but in your case, you should take it to someone who knows how to fix car, its well worth the headache down the line. But thats too late now. I don't remember if ours have diagonal brake lines or not. Get yourself a bottle of brake fluid because you will need it. Open the reservor cap and fill it full w/ brake fluid. Open all bleeder valve and let it gravity bleed. Make sure the reservor does not run empty. Close all the bleeder valve and close the reservor cap. Pump the brake pedal, slowly and easy. Do this serveral times and have someone open the bleeder valve on the rear. Then do the front, but do it diagonally like the a "X". If the pedal is still soft, repeat this untile all the air is out.

Thanks for the help. I fixed my brakes and they work fine now.