2001 Mercury Sable Bleeding The power stearing system

Hi maddog75. Welcome to the forum. Normally, all you have to do is turn the steering wheel lock-to-lock a few times to expel the air, but Fords seem to be a special case. They give a lot of people, including professionals, trouble. Very often the systems seem to work fine with no abnormal noise until you stop the engine. Then the trapped air will expand causing fluid to burp out of the reservoir onto the ground. From what I've heard, if you immediately refill the reservoir, that will prevent more air from being drawn in the next time you start the engine. You may have to do that a few times to get enough trapped air out to put an end to the burping fluid.

The alternative is to use a vacuum tool but I've never actually seen or used one. My experience comes from working at a Chrysler dealership. I've replaced a lot of rack and pinion assemblies but never had trouble bleeding their systems. Of the Fords I've worked on, I've never had a problem either after just turning the steering wheel, but the burping fluid problem is very common.

Caradiodoc

Removing the return hose is done to flush the old fluid out, typically after replacing a failed pump. Removing the hose to bleed out air would counter-productive as more air would enter the system if the reservoir ran dry.

Sorry I can't help with the volume of fluid in the system but that would only be relevant if you knew it was totally empty. Even after draining, there will be quite a bit of fluid hung up in the rack and pinion assembly. The best you can do is just keep the reservoir full. If I understand correctly, if you keep filling it after fluid overflows when stopping the engine, it will eventually expel all the trapped air into the reservoir.

Caradiodoc

Yup. The trapped air bubbles compress under pressure when the engine is running. When you stop the engine and power steering pump, the bubbles expand and push the fluid up into the reservoir. You might try running one front wheel up on something to make one side of the car higher, and then the other side to dislodge the air pocket. That procedure is actually shown in Chrysler service manuals but I've never had to resort to that.

I suspect part of the overflowing problem is due to people adding fluid to fill the reservoir while the engine is running. If you only add while the engine is stopped, the air pocket will already be expanded and the fluid will be at its highest level. The most important thing is to not let the level get so low that the pump draws in more air.

Caradiodoc