Brake light in dash comes on

[jwcain]

Hi all, hope someone can help me with this one. I have a 97 F-350 PSD and am having problems with the power brakes. The problem only happens when going down hill (crazy) the brake light comes on and when the pedal is press it really hard to stop, on Level ground it's okay. I've checked fluid levels and for loose vaccum hoses and the check valve on the booster. Anyone have an idea? thanks

 

[roger2003]

Do you have anti-lock brakes and I assume that you have drums on the back? I have heard of this problem with a anti-lock brakes, it's a bad sensor plug connection on the back axle.

 

[JLDickmon]

check the fluid level in the master cylinder

while you're there, if it has a switch in the nose of the master cyl, see if that's leaking (pull the wires off and look for moisture/brake fluid)