Issue with my brakes.

[aod92]

I was driving my 70 deville the other day and I lost my brakes. The brake light came on, and the pedal got real hard. Got the car home and noticed fluid around the top of the master cylinder. Took off the cover, and the rear of the master was empty. The front was over full and pushing out around the cover. This the master, booster, or a combo of both. Car looks dry everywhere else. Thanks!

[TJ Hopland]

If everything else looks dry then my first guess would be the MC itself.  It may have and some sort of internal failure between the two sections and its basically pushing fluid between the two sections.  If it was a leak elsewhere in the system you would usually get a soft pedal. 

[Glen]

I agree with TJ.  The cup seals between the front and rear of the master cylinder are leaking and the read is sucking air. 

An overhaul kit will fix that. 

[aod92]

I was also told the porportioning valve might be bad. Does that sound right?

[Dave Shepherd]

Unlikely, if that was bady ou would usually have either front or rear brakes working. Possible you are leaking back into the booster, you would see that by loosening the m/c from the booster for a look see.

[aod92]

Just installed a new master today and that was the problem.  But here's a weird one for you. I bleed all the brakes starting with furthest corner from the mc. I get to the right front, and I'm not getting any fluid out of the bleeder. Took it out cleaned it and still nothing.  The weird part is the caliper still works. The car stops great1 could the caliper itself be clogged right before the bleeder?

[Dave Shepherd]

Crack the line and see what happens.