brakes not working

[sixpack_sid]

It's not a mopar, but-my mom has a 98 chevy malibu and the brake line broke from the ABS unit to the right rear wheel. She drove it a couple miles that way to get it home. I replaced all the lines because they were all pretty rusted. I bled the master cylinder, then the abs unit, then all 4 tires-rr, lr, rf, lf. When she drives it now, she says the brakes go to the floor until she pumps them a few times, then they come up. Do I need to bleed everything again? If she ran the master cyl. dry, would that cause the problem? Is there a way to tell if the master cyl. is bad? I spent all day Saturday working on this car. I would like to get it fixed and out of my garage so I can focus on my 68 Charger resto.
Please help!!
Sid

[jpsycoboy5]

My 96 ram did the same thing how did you bleed the abs? I literally had to hook a computer up to is and use that to bleed the abs. Abs is EXTREMELY picky with air you need basically no air in the lines where are you located at? My friends shop has the computer you need to bleed abs

[sixpack_sid]

There are 2 bleeder screws on the ABS unit. I bought a repair manual that explained how to bleed the brake system-starting with the master cyl-bleed the brake lines by unscrewing them and pump brakes until fluid comes out and there are no air bubbles.Then bleed the abs by the 2 bleeder screws one at a time until no air. Then go to the wheels and bleed. Why do I need a computer to bleed the abs? It said nothing in the book. I live in eastern PA .
Thanks for the reply.

[jpsycoboy5]

The computer tells the pistons to open in the abs and you open the bleeder valve based on which piston was pumped. Maybe the car doesn't need to be done that way? But was the brake fluid ever changed in all those years? If not when the pedal hit the floor the deposits left in the mc most likely tore the o rings apart when it went to the floor since that last little bit of pedal never gets used that's where the deposit settles and when it goes to the floor it rips the o rings you can buy just the o rings but a complete mc is A LOT easier in my opinion

[FLG]

I agree, when the pedal went to the floor it probably cut up the o-ring on the mc from deposits.

[sixpack_sid]

Well, I got a new master cylinder and bench bled it before putting it on. The brakes still go to the floor. I ran out of time so I'll try to bleed the whole system again tonight and see what happens.

[jpsycoboy5]

If you replaced basically all of the brake system you had or have a lot of air in the lines if everything is replaced and your positive there's no leaks at any of the connections or anything then there is still air in the lines somewhere

[Back N Black]

If you replaced basically all of the brake system you had or have a lot of air in the lines if everything is replaced and your positive there's no leaks at any of the connections or anything then there is still air in the lines somewhere

I agree, are you just doing a gravity bleed or using a bleeder pump (vacuum type). or a buddy pumping the brake pedal, while you open and close the bleeders.