hi sages- this is embarassing since i have worked on dodge and plymouth brakes, cylinders, calipers since 65. on my 80 volare about a month ago , the pedal dropped half way to the floor and the brake light came on. there was a partial loss of brake ability. looked in the reservoir and the front chamber was empty(rear brake lines). figured master cylinder. replaced it and bled the chambers with the little hoses back to the reservoir, pumping the air out of the master until fluid flowed clear and no bubbles. had to replace one busted metal line from the cylinder to the proport valve. up jacked rear and noticed broken (rust) metal line from the rr cylinder to the brake hose on the axle housing. replaced it but it was a little longer than the original and had to put one curl around in it . bled the rr cylinder and the Lr cylinder. had good brake pedal and stopping abilitybut brake light on dash sometimes stays on or flickers. figured air in rear line or master. rebled both rear wheels and the master again. no change. did not bleed the front since those lines were not disturbed. no leaks or loss of brake function . never had a bad proport valve. know they work by sensing unequal front to back pressure through a double piston which moves a lever switch off middle. next step(try the easy stuff first) is to bleed the front brakes but doubt that is it since they werent disturbed or the fluid run out of them. has anybody actually had a proport valve crap out? fsm says not to take it apart. looks like lever switch on top would screw out with a small box wrench. part isnt available anyway. please advise if you think i am going down the wrong road. i invite your critiques. thanks tons bob fisher

Bob,

You have to bleed the front brakes to move the warning light switch back to it's centered position.

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Joshua