I am doing a front brake job on my 76 280. New rotors and two piston calipers.and i can not get the hubs off of the old rotors. any tips would be great.

Assuming that you have removed the 4 bolts that hold them together. Clamp the old rotor in a vise, large chisel in the joint between the rotor and hub. Beat the crap out of it!

Ok thanks. yes i have removed the 4 bolts and soaked it with PB and Beat the **** out of it. By chance does any one have a set of hubs laying around.

Mine were very difficult too. I ended up using a block of wood to protect the hub and beating it hard with a large mallet. When that didn't work on one then I use one of my favourite tools a BFS (Big F#$king Screwdriver) and positioned it between the disc and hub to use as a pry bar, without damaging the hub and only digging into the rotors. Then you work your way around the disc and hub slowly prying it out a bit each time it will eventually come out.

I locked the rotor in a vice and smashed down on it with a rubber mallet

Beat the stuffing out of it with a big dead blow hammer and then used a thin chisel and worked my way around the hub until it came loose. It was a big pain.

i placed something under the hub and held one side of the rotor while i beat the sh*t out of the rotor with a mallet, rotated rotor to evenly smack it out, just keep at it and hit it VERY hard