73 dart OE disc drum. pedal goes almost all the way to the floor & it does not pump up. pulled one front/rear (hard to get the lug wrench on the nuts on the mag wheels so just did one side) & up front one pad of the two was pretty thin as was one of the linings on the left rear & the drum did not seem loose on the linings when I pulled it. M/C is about 3/4 full. any thoughts on what might be the problem here? thank you for your time. RR