Quote:
Originally Posted by DieselAddict
That's like saying draining oil from the oil pan accomplishes so little that it's not worth doing. The method that I described removes most of the PS fluid from the system without requiring an assistant or running the pump partially dry. You've obviously never changed the PS fluid on a W210. Even a few left-over bubbles in the system can make some awful grinding sounds when the PS pump starts running. The only way to prevent that is to bleed the system entirely before turning on the engine.
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A rack and pinion is a whole different ball game, but yes I have indeed flushed a few of them. In those cases you have to crack a line to bleed it sort of like bleeding injectors.
The flush method that is talked about in this thread is what I call the ASE method. The reason I call it that is this is the method in the ASE test and is widely accepted. Flushing a power steering system does a better job by at least an order of magnitude as compared to draining most of it.
Engine oil is a totally different issue. Engine oil typically gets drained and replaced often and for good reason, there are combustion byproducts and all sorts of contaminants and acids that appear in engine oil. P/S, or most any other hydraulic system for that matter, have to be flushed to remove metallic particles and oil that is tired from heat cycling. Engine oil typically gets changed for contamination reasons, not because of lack of lubrication ability.
In the case of the MB there is a filter, but most P/S and many hydraulic systems have no filter. The filter takes care of the metallic particulate, but can do nothing for the tired oil. SOooo.... following the "ASE Method" is not as important on an MB, but IMHO it is still a very good thing to do every 150,000 miles or so.