GMC Repair: brakes, parking brakes, fluid leak

Question
QUESTION: I have lost most of my braking pedal, about 2/3 to the floor. I have to pump it a couple of times. I went to change the front brakes, but they seem to have plenty of wear left. Half as thick as the new ones, but plenty of pad before the sensor. I just had the parking brakes worked on, they did'nt say anything about the rear brake pads so I assume they are ok. Should I go ahead and replace the front pads? I did add some brake fluid a few months back when I first noticed this braked loss. Did'nt seem to help. Thank you for your help, John

ANSWER: not sure what kind of vehicle you have but it sounds like you have a fluid leak issue

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QUESTION: It's a 2002 Silverado, could it be the master cylinder? I have'nt noticed any leaks, but I'll look and see if I can find one.

Answer
it could be the master but unfortunately we see a lot of those trucks and its usually the brake lines themselves, sometimes in the rear, and sometimes in the front, repalcing them is quite a job, not to mention you will need a scan tool to activate automated bleed to get all the air out