A popping noise and grinding a/c compressor new

When I take off there is a popping noise and when I
brake there is that same popping noise in the front
end. Any ideas on what yall think it is? And second
question just bought a a/c compressor with oil
inside if it. I had a vaccum pulled on  it and and
added 3 cans of freon and the first couple days it
worked fine now it's got a grinding noise every now
and then like maybe a bearing is going out. Any
ideas before I return to get a replacement