Brakes 1985 CJ7 New Master Cylinder??

[markwiley2121]

New to me 1985 CJ7 . I recently changed the rear drum brakes, including the wheel cylinders. No apparent brake line leaking. I replaced the brake fluid, and bleed all four brakes (multiple times now). When I took it for a test drive, the brakes responded ok, however I could not lock them up. Also, when stopped and applying moderate pressure the brake pedal slowly went to the floor. When I let up, it returned fine. If I pump it a few times, or push hard suddenly, the pedal stopped halfway down, then slowly sank to the floor. With no leaks, new brake fluid, all bled well, it has to be the master cylinder right? Any other options?

 

[hole]

Try bleeding fronts first, then rears, then fronts again.

 

[Lumpy Grits]

Did you bleed the MC, before attaching the lines?
Are you SURE you have the correct MC?
Why did you replace the MC?

 

[markwiley2121]

I didn't replace the MC, I'm wondering if it's bad though. I didn't replace the lines either, they look good with no leaks. I just replaced the drum brakes and the wheel cylinders. I also bleed them twice, once I did it rear passenger, rear driver, front passenger, front driver. Then after a test drive I did rear passenger, front passenger, rear passenger, then the same on the driver side, I read that pattern somewhere before. The second time, no air bubbles came out at all.

 

[Lumpy Grits]

Replace the MC. Sounds like the internal separator seal is leaking.

 

[mtnwhlr]

Replace the MC. Sounds like the internal separator seal is leaking.

And bench bleed it before installing.