You won't know what is really going on until you get a pressure gauge so you can see what the line pressure is. Just like guessing what your oil pressure is by looking at the bearings.

Get a pressure gauge so you can measure the pressure in the front line and the rear line. Once you know what the pressure is you can figure out what each end is doing when you stop. There are all kinds of reasons why the brakes aren't working properly. Could be a smashed line, something out of adjustment, a blown seal, etc.