BMW 523i Workshop Manuals
If you have to conduct fixes to your BMW 523i then it is usually recommended to have a Workshop Manual to use as a reference in case you need to know the right way to remove a particular part including Drive Shaft and fit it again in the correct way.
BMW 523i Workshop Manuals will give certain diagnostic information on your vehicle so if something is broken it can help you determine what the issue is and some ways to correct it. You can then assess if you can do this yourself or if ever the job is simply too big you are able to book your 523i right into a suitable mechanic.