Plant material is surprisingly abrasive stuff. Constant churning abrades the steel and rubber of a diet feeder’s internals: the result is that mixing efficiency falls, the drum or tub wall wears thin where pressure is greatest and, if left, will eventually fail. On top of that, soil particles carried in on crop material, plus attrition from plant acids, take an extra toll. Patching will keep a machine going for a while — but, where a feeder’s chassis, driveline and weighing equipment are in good order, a proper rebuild may be more cost-effective than machine replacement. Plan the job, get the right bits in hand before you start and the unit will be back in service fairly quickly.