Does anyone know why my walking foot loosens the needle and I end up with a broken needle..? I have tried everything I can think of, and still am breaking needles right and left.
Please, I need help!

Mine doesn't do that. Maybe it is the little lever that sits on top of the screw for your needle. It might be vibrating the screw loose. Try tightening your needle with a small screwdriver. It can't hurt.

You many need a new screw that holds then needle in.
The threads on the screw could be worn causing the screw to become lose. It could have bad threads from day one and is just now showing it. A hardware store should have the tiny screw , cheap, you could try to see if that is the problem before buying one that goes with the machine.

The screw holding the foot can loosen if not tightened very well. Also, my machine needed adjusting as the needle was hitting the leading edge of the walking foot and breaking. After four broken needles and much frustration, I took it in and servicing corrected the problem.

Thank you for all your suggestions...I talked to my sew and vac man and he suggested I needed a new screw with a smooth area to hold the walking foot attachment...great! It is being ordered and in two weeks I'll give an update. Again, thankx.