Sounds like your power steering pump is either dry or failing. First check the fluid level. Open the hood and you will see the reservior on the right side of the motor front. You may have to lift the engine cover to get the cap off. If it is low add fluid, if it has enough fluid you may need a pump. Also keep an eye out for leaks. This model ML is notorious for power steering leaks at the reservior.
Saturday, January 3rd, 2009 AT 11:50 AM