As of a week ago my brake pedal has been slowing "fading". Don't know if that is the right term. It's kinda weird. At a stop, if I have constant pressure on the pedal it will hold. However if a let off a little bit, the pedal will slowly sink in. When I pump the pressure gains back up again. There are no signs of leaks anywhere.
SD Yota and I worked on it yesterday and from what he sees and tell from driving it, he thinks it's the master. Any thoughts or input? Thanks in advance.

 

You'll find oil behind the seal when you pull it,can rebuild ,but I'D JUST GET NEW!!

 

mine is doing the same thing I have replaced wheel cylinders and bled out the system completely so I know thats my next step

 

If it has no signs of leaking at the wheel cylinders try bleeding first then if that doesnt fix the issue then is may as well be the master cylinder. luckily our truck parts are cheap and thats easy to get to and replace.

 

At this point I might as well do the vented rotors and IFS caliper upgrade with the 1" bore master. But of course no funds to do all this. I probably should just change out everything considering it's a 25 year old truck and none of those parts haven't been changed yet.

 

the only way to be sure is take off the drums and look, just because it looks fine with the tire on and stuff doesnt mean its not leaking! it happened to me, i had to add like a teaspoon of brake fluid every month or so and there were no leaks i could spot, then one day i took off my tire and took off the drum and...BAM fluid everywere inside all burnt and gunky, i thought it was my seals but after a close inspection it was the cylinders.

 

I did a brake stand once and blew a line on the rear end. But it took a while for all the brake pressure to be lost. Going over the brake lines intently can't hurt.

 

it's probably your MC like everyone else has said..mine was leaking bad but like stated above once you take it off you'll probably see it leaking...Don't buy aftermarket either..I went through 2 aftermarket MC's finally this last time i bought an OEM Aisin for about $75 shipped

 

It ended up being the MC and I did get a Aisin one. Like Joey said, I figured for a few more dollars I can get an OEM one rather than a aftermarket and not worry about having to switch it out.