When was last time you flushed brake oil ? Yes compared to car.. yes mine is hard.. you may be due to lube the hydroboost actuator rod.. some models have grease fitting and some you need to spray lube... some models the brake rod is under hood and some under drivers feet.. get to it under drivers side front tire.. I can't see your year and make of chassis.. so that is on my set up.. yours could be a little different.. hard peddle better than .. sinking feeling you get.. when you get soft peddle.. oh.. there is a guy.. working.... or experimenting... on p32 brakes.. on you tube.. very interesting.. really good to watch.. p32 brakes..
Good luck and keep us posted
2000 southwind storm, workhorse custom chassis with 7.4l vortec