Brake SPONGINESS

My brakes are really spongy on my 90 XJ. Like having to push to the floor spongy. Figuring the possibilities here...
I just replaced the front rotors and pads and the rear shoes. What could this be here....... Im thinking master cylinder?Maybe?

First guess, air in the lines. Second, bad brake cylinders. Third, calipers. Check all your fittings and lines for leaks. Pump the break pedal, if it buils pressure, chances are you just need to bleed the air out.

I've got a rear grease seal out on the back left wheel but I'm not sure if thatd make a difference. ?????

Is the fluid low in your master cylinder? Are you sure it´s an oil seal and not the brake wheel cylinder passing brake fluid? Pull an edge of the rubber dust seal on the rear brake cylinders and look for brake fluid (part of a normal brake service), on the wrong side of the piston. If the brake fluid leaks out of the wheel brake cylinder, air can get in. A leaky wheel brake cylinder, will often fail to retract all the way, along with the spongy pedal, the rear brakes often drag and grab.

First thing I would do is bleed all four corners (start with the right rear, left rear, right front, then left front... farthest to closest from master cyl.). If that doesn't clear it up, I would definately look at that rear seal issue, because it may not be grease but brake fluid leaking out in the back. I had a leaky wheel cylinder on one of my rears and coupled with well-worn pads and siezed adjusters, it made the brakes very mushy.

Also, when you replaced the rear shoes, did you check that the self-adjustment mechanisms were working right? If they're siezed up, the rear brakes won't adjust correctly and it will cause mushiness and also cause your rear shoes to wear funny. You can adjust them manually as well, sometimes this works to break the adjusters free if they're siezed. In my case, I had to remove both of the adjusters and heat them with a torch to seperate the two pieces as they were rust-welded together. Put some anti-sieze compound on before re-assembling

I always keep the fluid level up but i suppose it could be brake fluid coming out. I'm going to take it somewhere because brakes are something I hate to screw with. Just wondered if it was the master cylinder mainly cause I'd tackle that one myself but it sounds like its not. Thanks all.