[XSL_WiLL]

I have the older G1 style caliper Hayes HFX Mag HD. My rear brake is messed up. When I grab the lever, there's pressure, and the pads grab the rotor, but if I hold the lever down, the pressure goes down, and the pads back off, this continues until the lever is all the way down to the bar, and at this point the pads just barely contact the rotor. If I let go of the lever and grab it again, the pressure is back momentarily before slowly backing off again. I'm not sure if it's just a pocket of air, but it feels as if fluid is leaking out somewhere, or forcing itself back into the master cylinder.

 

[RED5]

definitely sounds like you have air in the system. Rebleed or have them rebled and you should be fine.

 

[SHIVER ME TIMBERS]

sounds like a hole in your line....check for kinks in the line and replace the line if you see any bad kinks or glistening parts to the line and then rebleed

 

[dogonfr]

My sons did the same thing, finally found a hole in the hose after about 2 weeks of bleeding & rebuilding the master.