Leak from iron y connecter between tub drain and trap pipe. Can this be fixed without replacing all pipes? I have some access from hole in adjacent wall.

Is it cast iron or brass? Where Is it leaking? Are there large nuts on the fittings?

how to fix a leaking elbow from tub drain Leak from iron y connecter between tub drain and trap pipe. Elbo, wye?? I don't see either one.
More details please! Iron pipe? Cast iron or galvanized? Here's a typical bath and trap connection, (see image) Show me the wye you're referring to. Would it be the tee?

Can this be fixed without replacing all pipes?
Most likely. Is this a leak from a compression joint or a threaded connection? Back to you. Tom