The brake master cylinder may leak fluid internally past a seal and into the brake booster. This will cause braking performance to deteriorate. Dealers will inspect the master cylinder and replace it if necessary. This recall began on July 23, 2008.
 
Recalls
Recalls are issued for cars with safety-related defects or problems
2007 Nissan Sentra
Brake Fluid May Leak from the Master Cylinder
Brakes, July 23, 2008