the brakes on my 82 have decided not to work except when they want. this is a problem for me seeing as how they dont like to stop at stop signs, garages, etc. anyway i am pretty sure it is b/c my master cylinder is leaking. i am going to replace it, yes i know that it leaking will eat up the seals in my booster. i was wondering though, would they leaky cylinder and the air bubles in the lines that follow, cause just my rear brakes to work. it works like this, i step on the brakes, and sometimes(alot today) the pedal goes all the way to the floor, brake light comes on, but my rear brakes still work (front ones do not grab)... i dont understand why they work. could someone please inform me.

do you still have rear drums?

my 81 did something similar just before the drum brake cylinder blew out. nice and messy because them fluid gets over everything and you have to clean it all. If that's the cause you've got about 2 weeks depending how hard you are on them i guess.

Have you checked the condition of the front brake hoses (caliper to brake line)?

i have rear drums, just replaced the shoes. hmmm.. will check the hoses tonight. thanks guys.

Your brake system is split,with the rear section controlled by half of the master cylinder and the front by the other half of the master.It is very common for a weak master to fail when it's cold.The wear on the seals allow's an internal bypass.Usually the larger reservoir serves the front and the smaller one the rear.DONOT KEEP DRIVING!!!REPLACE the master before you kill yourself,or worse,someone else.
Don't forget to bench bleed the master before installing.
ALSO,remember that brake fluid absorbs water,use only fresh fluid from a sealed container and DON'T leave the caps off while bleeding.
8) Shane

P.S. If in doubt,let a professional do it for you.Brakes are too important to guess at.

Have you determined where the fluid is leaking. I've had two 5th gens, and the front right brake line got a pinhead sized rust hole in both in the exact same location. The location is outside of frame and behind the right front tire about 6" back from where the hose attaches to the brake line.

im driving my 94 1500 right now. ive already got the new cylinder coming, not too sure on how to bench bleed so im getting a mechanic here in the shop to do it/show me how. thanks for the input, i knew it was the cylinder, but wasnt sure why the back still worked. any way thanks alot!!