this is submitted without predudice and in no way is meant as an encouragement to work on any Electrical appliance unless confident or qualified to do so.
May I suggest carrying out a light item wash, very few items along with one heavy item like a pair of jeans then see if the vibration is still there. unless of course you have already done this then follow the rest.
Could be vibrating violently because you overloaded the machine especially with heavy wash items like jeans.
Overloading prevents the machine from distributing the weight as even as possible.
1. A balance weight/spring broken or weight loose.
My machines weight spring broke and caused a violent vibration throwing the drum into an oval spin until it evened itself out.
Slow drum wash tumble no vibration. A spin violent vibration.
As for the leak I can only guess the vibration has caused one of the pump hoses underneath the machine to leak if the others are ok.
If you can pull the machine out of its parked area and use it, the make sure the floor area is dry and place a tissue on the floor under the machine in line with the pump or hoses and lower the machine then do a small short wash. you will then maybe get an idea where the leak is coming from.
If you haven't worked on a washing machine before keep the drain hose up above the drum level to prevent possible water syphoning from the drum, the metal drum might be dry but the drum that revolves in isn't always completely free of water and if you allow the hose to rest on the floor you may get water syphoning out of the hose.
Sorry can't be more helpful but these are from my own experiences.
Luke Smith, January 2005
