MIKE'S CORRECT. MOST FARM STORES SELL NEW WELD ON ENDS.
oops.. caps...
I have seen balls for sale at tsc.. but it takes special finagling and extra, extra work and fabrication to put in a new ball.. I've done it on a ford with 2 large machine bushing flat washers, a lil welding, peening and grinding.. but new ends are way easier...