We had a AC 190XT brand new and the brakes were never that good on them when new as they were all mechanical (no power or vacuum assist) unlike the old Farmall IH tractors of that era (706,806,1066) that had power assisted and would lock the wheels with just a touch.
Holding down on brakes to heat up oily shoes usually just turned them into glazed shoes that were worse. Have to replace the brake linings, fix any oil leaks and then you will have some fair brakes, not great brakes but sufficient for the job if you have strong legs.