CDC'c answer is of course the correct and proper method but there is another which will allow you to replace your old ring.
Bend the old ring apart and slide the rubber boot back along the drive shaft if possible.open the old ring up enough to get it off the drive shaft, clean it up as mentioned above.
Put the boot back temporarily and clean the ring seating with first a strip of rag moistened with de-greaser (not too much don't want it getting into the bearings) then with a bit of emery. Next put a ring of Tiger seal around it put the ring back on and tighten a large jubilee clip around it. In the morning it will be absolutely solid. Did mine 3 years ago and it's still working. Best thing is you don't need to remove anything but the wheel and if you break your ring you can put it back in separate pieces and it still works!
Bodge
January 2014