I have a small out of ground pool the pump all of the sudden stopped working and keeps tripping the breaker. I took the pump apart and oiled it. Before I put it all the way together I turned it on without the housing for the hose, and it worked fine. But when I put the housing back on and turned it on it lasted for about 45 seconds and tripped.

Sounds like you have a electrical short between the hot and the ground. Motor would probably run on the bench because you did not have it grounded. Assuming a 120V motor, try reversing the black and white wires at motor connection as a test. Motor will run that way. Don't touch motor, you will probably get shocked. Then disassemble and look for short.
Another test of theory would be to disconnect ground and try motor. However piping and water in pipe might still provide ground.