WD2500SB Only shows 175 Gigs. Hidden RAID partition?

I purchased several used 250 gig drives (WD2500SB RE).  When I attempt to format the drives they only show a 175 gig partition.  Is there a tool to access the entire drive?  

You can try running a test with DLG, if the test completes successfully, try running zeros and then try formatting the hard drives again. Check the links below for more information. 

How to test a drive for problems using Data Lifeguard Diagnostics for Windows

How to low level format or write zeros (full erase) to a WD hard drive or Solid State drive 

Thank you for your suggestions.  I attempted both of those last night before posting.  No change.

Is it possible that RAID software allocated a slice of the drive for overhead?  How can I check that?

Would modifying the cluster size make a difference?  

Should I attempt to format it to FAT32?

I’m really just grasping for any solution.

For the benefit of other users I will list how I resolved this problem.  I used a small program from Atola Technology called

HDD Capacity Restore Tool, which is listed in the instructions here:

http://blog.atola.com/restoring-factory-hard-drive-capacity/

In just a few seconds it restored the entire drive capacity for my use.  I strongly encourage you to read through the instructions before operating the program to ensure the safety of your data.  I was operating on empty drives so I was not concerned about data loss.