Originally Posted by LarryBible

Over the counter P/S fluid from the auto supply will work just fine.

There is no set interval for changing power steering fluid, but it will go a LONG way. Since you are replacing the hose, this would be a good time to do a proper flush, and filter replacement.

This is best done with what I call the "ASE Test Method." This is very simple, can be carried out quickly and does a THOROUGH job. Simply sucking out what's in the reservoir and replacing it will accomplish little or nothing.

Here's the test procedure: Have four or five quarts of fresh P/S fluid and a new P/S filter on hand. Empty the reservoir of fluid and disconnect the return line from the power steering pump and lower it down into a drain pan. This is very easily done on most all MB's. Plug the hole from which you removed the return line and stand by with two quarts of clean P/S fluid. Have an assistant start the car and begin turning the steering wheel back and forth lock to lock while you pour the P/S fluid in as it takes it. After the two quarts have been poured through and as soon as you hear the system go dry, and there will be no mistake about it, OR when your assistant finds the steering wheel very stiff to turn, immediately shut off the engine.

NOW... Remove the reservoir plug and reconnect the return line. Replace the filter at the bottom of the reservoir and fill the reservoir with fluid. Have the assistant start the engine and begin turning the wheel back and forth again while you begin filling the reservoir. Turning the wheel back and forth bleeds the system. After it is bled, working well and filled, seal it up and drive it a day, then recheck and top off the reservoir.

If this procedure is followed about every 100,000 miles, you will have long p/s life.

Good luck,