If you have to accomplish maintenance tasks on your Vespa GTV 125 then it is always a good idea to own a Workshop Manual to keep just for a reference should you want to know techniques to remove a particular component for example, the Brake Pads and install it again properly.
Vespa GTV 125 Workshop Manuals will give you special diagnostic facts with regards to your car or truck so if something is broken it will help you identify what the issue is and tips on how to make it better. You can then evaluate if this can be done yourself or if the job is just too big you could make a booking for your GTV 125 in with a local repair garage.
Vespa GTV 125 manual