how to fix the front axle shaft on my car?
change it is the only way to fix that.
Most of those are not replaceable unless you take out one of the tile ends too. Try a good tile store that specializes in bathroom fixtures and bath tile. Or, try a place that specializes in bathroom renovations. If you measure the towel bar, I'm sure you can get a spring-loaded towel bar that you can replace these with, or an adjustable bar like the ones for shower curtains. You may even be able to custom make an adjustable bar online.
If we knew the car, that would help.
depends on the car, but buy a new axle, pull the wheel off, remove the grease cover. remove the axle nut, pop the lower ball joint off, this should give you enough room to get the axle out of the hub, might have to turn the wheel all the way one direction, its usually tight. then pull the axle out of the transaxle. sometime this takes a slide hammer or some pulling to get it to pop out. put new axle in and reassemble. this is vague due to you didnt mention what kind of car.