94' Buick Le Sabre brake problems

On Sunday (5-17) I drive home perfectly fine, but Monday (5-18) I left the house only to realize I had no brake pressure. I had to press the brake to the floor for it to start slowing down, I found a slight leak in my driver side rear brake cylinder so I replaced both sides and bleed the brake lines. Still no pressure, so I bled all 4 lines. I could feel the petal give when bleeding all the brakes except the rear drivers side. Finally got it to give some after bleeding it 7 or 8 times but it's still going all the way to the floor. There's no pressure building in the petal, what else should I check? Help!

If you lost all the fluid in the master and abs, using a scanner to bleed the system may be required.

In addition to what Max said, double check the back of the M/C, for fluid dripping down the booster.....

As Max asked, How much fluid was lost in the M/C? If nothing appreciable, could be a bad M/C...

There was no loss of brake fluid, so the master cylinder didn't suck air in that way. There is no fluid leaking from the m/c either. The cylinder on the passenger rear has bled fine and I can hear the brake pad grabbing on the drum but the drivers side rear isn't bleeding and we can't feel, see, or hear the break grabbing the drum.

I assume your vehicle has ABS?

How are you bleeding? With key out of the ignition, do you have someone else pump the brake pedal until you have a hard pedal and then hold down on it? And then do you open the bleeder?

So nothing comes out of the bleeder on the on the DS wheel cylinder? Have you tried cracking the line at the wheel cylinder? Still nothing? Then trace the line all the way back to the ABS PMV, and break the line there while holding pressure on the brake pedal.....If nothing comes out there, then you may have an ABS PMV problem, and check for ABS codes.....If fluid does come out, then check that line for a kink somewhere.....

Yes I pumped the brake pedal and held while my dad opened and closed the bleeder. The brake pedal isn't even building pressure when I pump it up. One of the times the pedal made a popping sound and I could feel it give in my foot. We have tried it with the car off and with it running there's still no pressure either way and we're not getting and fluid from that rear drivers side. Followed the lines from the bleeder all the way from the bleeder to the master cylinder and can't see any visible kinks. Could there be a clog somewhere in the brake line? Or something I should be doing differently?

Somehow we need to determine the failure for the lack of pressure at the driver side rear. You mentioned the passenger rear cylinder bled normally. Assuming this is correct, then our master cylinder and booster must be functioning properly. So, our issue lies where the hydraulic system splits off to the driver rear wheel. One item that comes to mind is a collapsed brake hose at the driver rear wheel. It's more common for a brake hose to fail on the return side of fluid flow, than the pressure side. But anything is possible. I would recommend cracking the line in front of the brake hose for the driver rear wheel. If you have pressure at that point, we've narrowed down our area. If there is NOT pressure, then we need to focus forward more.