I have this problem in my mostly stock 2001 also. I've barely been able to stop a few times and I cant seem to find anything wrong or anything else that would cause it.

 

Do it to both brake lines on Master cylinder.

Don't pump the brake pedal.

Do one line at a time.

Crack one line at the master. Then have the person push the pedal to the floor.Tighten brake line back up before the person lets go of pedal.

Repeat for the other line.

 

Bleeding didn't do anything for me.
I did fix it though. It was the brake booster (valve $75.00).
Truck is stopping again, nothing wrong with master cylinder, so don't just run out there and buy one, have someone check the booster first.

 

Brake booster valve located on the frame rail?

 

More description? Part Number?

Thanks

 

I've noticed it too on my 2002, now equiped with Hawk HPS, and before with OE, and also on my 2001. When braking over choppy surfaces it seems to cause havoc with the ABS. Sometimes i've experinced uneven braking on random moderate braking - I think it's all ABS related.

 

Ditto...every time I pull into my driveway over the bump, my ABS kicks in. Seems we all have the same symptoms. Its starting to get scary driving at times when you know you can't brake the way you know you should be able to.

 

I'll get the part # to you asap.
But I have to say it's not all fixed, still working on it...just got a little better