I'm pretty sure you have mechanical disk brakes, probably very low end SRAM Avid's, which I've had previously on a couple of other bikes and I could not stand them, heavy bike or not. Do yourself a huge favor and replace them with hydraulic brakes. You don't even need to go to a bike shop to have them installed if they are pre-bled.
Tektro Auriga front/rear $70 total.
Shimano XT front/rear $200 total.
Either one of those will be a huge improvement over what you have now, even the Tektros.