A stub axle is one of the two front axles that carry the wheel in a vehicle. It allows for movement around the kingpin, which enables steering in the vehicle. It is made up of wheel bearings that support the wheel hub. It gets its name from its resemblance to the shape of a stub, similar to the truncated end of an axle. It is short and blunt in shape. Usually this component in a vehicle is a long-lasting component but in the event of it getting either damaged in a vehicle, or experiencing breakage through wear and tear, it can easily be replaced by a qualified mechanic. Typically, the stub axle is connected to the assembly of the wheel.
Most axles are bolted into the wheel assembly and can be removed and replaced by loosening a few bolts and sliding the broken stub out of its housing. If it is enclosed in a case, the entire assembly will need to be removed. This will require removing the springs and shocks in the vehicle to gain access to the stub axle. The stub axle receives a lot of strain and stress during the driving process, so fitting a new part is always best.
While some axle failures can be welded, in most cases this is not advised. The stress and leverage on a stub axle is so great that many welded ones can break during a typical turn. This causes the repaired stub to strain and pull against the weld. In most cases, failure will occur with the axle breaking off at the weld. If your stub axle is broken, replace it with a new piece as soon as possible.