having problems with the brakes on my 580K, it say to add DOT3 to reservoir and I have but peddle still goes to floor
First if its a US machine it does not use DOT 3 fluid in the brake system. DOT 3 will cause the seals to swell. The system uses TCH fluid in them. Most of the time the master cylinders and slave cylinders will need to be rebuilt or replaced along with the flex line at the brake housing, system flushed out. The other issue is the brake disc and plate wear, this being a old unit may need a brake adjustment or the brakes may be gone with no adjustment left or metal to metal worn out. The bleeder screw is on the slave cylinder above the brake housing and is easy to bleed out with a helper. Where are you reading to add DOT 3 fluid, book/cap label/ raised letters on the cap? Does Your machine have 1 rear backhoe boom cylinder or does it have 2 boom cylinders to raise the backhoe up?.
Also there is a equalizer tube between master cylinders. If the check valve leaks, fluid will flow to the other reservoir. A simple, cheap fix. If brake works OK two pedals at a time check this. Willie