Western Digital will usually have a utility you can download and check the drive but this might need to erase the drive to do the test. So I will assume this would be a last option type of thing.
Can you download a third party disk partitioning software you could boot to and look at the drive, or put the drive in another computer?
You may want to get another drive to replace the current one, then see if you could boot with it installed to see if you could copy your data from it.
If the repair is running that long, it probably means the system is having problems accessing the drive. Maybe try re-seating the connections or putting the drive on another port.