[ryans01]

might have some air in the line...possibly

 

[6isGood]

Doesn't sound like brake fade, you got bigger issues. Vacuum leak maybe?

 

[Buck08]

master cylinder might be leaking internally. or it could be a booster problem.

 

[ryans01]

and this is why i like brakes on older gasser trucks...

 

[totalloser]

I think buck08 has it. I think you have worn seals in your master cylinder. If you push the pedal slowly it should go more readily to the floor, or halfway down depending on if both seals are bad. If you push it fast, the abrupt pressure will make the worn seals open up like an umbrella, and they won't leak.

Be careful replacing it. You DO NOT want air to get to the abs unit. It is a true pain to get the air out, and it makes your rears lock up until it does.

 

[dodgerebel1]

the brake booster can be going