This is one I vaguely remember from my childhood. Tom Cruise is taken under the wing of Charles Bronson who teaches him the fine art of being a mechanic, not the type that deals with cars. Tom Cruise ends up killing Charles Bronson.
Surely, you're thinking of The Mechanic (1972), but it wasn't Tom Cruise, it was Jan Michael Vincent. Tom would have been ten years old when The Mechanic was filmed.
Yes, it's The Mechanic.