Sohc Turbo

How it going everyone.. I just need some help on a turbo... i was helping a buddy of mine build his d16 turbo.. everything was fine until we start it.. oil start leaking from the turbo.. the oil is coming out from the end or the blade for the intake side. i figure that the seal broken.. and i want to try and rebuild it.. Any change anyone no how to rebuild a turbo and where can i get the seal for me.. to rebuild the turbo.