After completing most of the mission you get dropped off at Los Santos customs in order to repair the broken car. Once Michael drives away in the cab you must enter the shop to repair the car and complete the mission. When I enter, nothing happens. The car breaks for a moment as if something is going to be triggered for this, but then nothing happens. I can't repair the car or even interact with the garage. I have replayed the mission and the glitch still happens every time.
As far as i know, this issue can be caused when you suspend the system during the mission. when you reload the game the mission becomes glitched when you get to Los Santos customs. Other people have suggested it happens if you play online before playing the story. It is hard to know the issue but there are ways to get it to work.
It seems as though there are multiple possible fixes for this, just like there are multiple causes. I will list the possible solutions based on how easy they are. Try the easy ones first and resort to the final ones if you still can't complete the Father/Son mission in Grand Theft Auto 5.
- Restart the mission and try again
- Restart the console, load up GTA and try the mission again (worked for me both times)
- Exit the game, delete the game data (NOT SAVE DATA). Re-install the game and try the mission again.
This glitch has been around for a while and Rockstar isn't fixing it, so if you have found a better solution or some reason behind the cause, please post in the comments below. Hopefully, this will be a way to easily get to the bottom of the issue.