The other day driving to work I suddenly lost my brakes. I was able to stop by pumping, but needed to find the problem. So today I replaced the pads and rotors, but that didn't really help.

So now I am going to bleed the lines, but if that doesn't work I would really like some advice on what else it could be. I don't have any leaks. The only other thing I can think of is the Master Cylinder lid is not sealing. Any other ideas. Thanks.

 

if you bleed the brakes and it doesnt fix it and thier are no leaks in the line Then i would say your master cylinder on the firewall is toast.

Sometimes the piston seal goes bad on them. You can seperate the master cylinder from the brake booster and see if it has been leaking fluid.

 

When you bleed your brakes, try powerflushing them...dirt tends to get sucked back up into the lines on these older XJ's. I had that problem on mine and it took 8 quarts of brake fluid to clean it out.
Other thing I could think of is that it could be the power booster instead of the master cylinder. Mine went dead and the MC was still good. Replaced it with a later model one from I think a 92 xj? Well, it was just slightly bigger, but it works great with no mods.

 

are you leaking brake fluid at all