No way a weld/braze repair would work and hold well. You'd be much better off making a new part. Or, much preferable to buy a rebuild kit or parts if you can find them.
If you want to repair yourself, buy a piece of tool steel the correct thickness, use a dremel tool and cutoff wheels to rough out the outline, file to shape. Probably a 2 hour job, maximum if you have any skill at all at this. If you have access to a drill press, you can drill numerous 1/16" dia holes along the outline and get a big jump start on the cutout. Or, if you have access to a vertical mill, you can scribe the outline, freehand out the outline, and then refine it. I've made numerous parts like this freehand on the mill. Not really cost effective for a $20 ratchet, though.
good luck!
dave