If a rumbling sound has recently led you to the laundry room, where you discovered your washing machine was having a dance party without you, then you have a problem that needs a remedy quickly. There are several reasons why a washing machine may suddenly begin shaking violently to the point that it walks or dances across the floor. These problems can lead to floor damage or damage to the unit, and could even pull water or drain lines loose. Fortunately, most of the causes are easily diagnosed and fixed.
Washing machines are meant to sit level on the floor. If they do not, the spin cycle may make the machine vibrate severely. To help machine owners keep the unit level, the bottom of the machine is fitted with adjustable legs that screw in and out to adjust the machine to the floor on which it is sitting. Check your machine's legs to make sure the unit will not rock back and forth. If it does rock, then you will need to adjust the legs until it will not rock. If it won't rock, it probably won't dance.
A simple solution to a dancing washing machine is redistributing an off-balance load. When the machine begins to spin the load to wring out the water, it is important that the laundry inside the tub be evenly distributed. If too much laundry is on one side, the centrifugal force will cause the machine to wiggle back and forth. A severly off-balance load can cause the machine to rock so hard to one side during the spin that the machine will shake violently and hop to one side.
If the floors in your home are not stable, the machine vibration could allow it to move across the floor. A properly balanced and levelled machine will probably be OK, but if the floor is weak and has a lot of "give" in the boards below, the machine will only be as stable as the floor on which it sits. A slightly unbalanced load or improperly adjusted level leg may be enough to send it gliding across the utility room floor.
Balance Spring Brackets
The spinning motor of the washing machine is fitted with a balance spring that helps keep the rotating tub balanced so it doesn't move around and cause vibration. But if the brackets where the spring is mounted inside the machine break, the balance spring can't do its job. You'll have to replace the broken brackets to fix the problem.