I rarely second-guess a professional who isn't here to explain his diagnosis, but the way you describe it, it's starting to sound like, "since you have your wallet open, I also found... "
These cars have relatively little trouble with their power steering components. The pump can cause a high low pitched buzzing noise, or, if worn, it can cause lack of power assist at idle. The clue is it affects steering effort equally in both directions and power assist will come back if you increase engine speed just a little. The rack and pinion assembly can cause lack of power assist in just one direction but that usually goes away as the power steering fluid warms up. GM had a real lot of trouble with that in the 1980s, but Chrysler products had very little trouble. There were some issues with squawking mounting brackets on the rack and pinion assemblies in older Intrepids. Rubber isolators were sandwiched between the brackets and the rack and pinion assembly. That rubber could dry out and cause a crunching noise as they flexed under the pressure of turning the wheels.
Shimmying is almost never a symptom of an alignment problem. At highway speeds, that indicates a tire balance problem. At low speeds, look for a bent wheel or a broken belt in a tire. There are three things you can watch for that indicate the need for an alignment. The first is the most obvious, an off-center steering wheel when you're traveling down a straight road. After an alignment, a conscientious mechanic will make certain the wheel is perfectly straight. If other steering or suspension parts shift position, (such as from hitting a curb or big pothole), or wear, it will reposition the wheels and cause the steering wheel to change position slightly. That's your clue that it might be time for an inspection.
The second thing to look for is what happens when you let go of the steering wheel. The car should continue straight ahead for quite a ways. If it immediately steers for the ditch or into oncoming traffic, an alignment is in order. A pair of tires can develop a pull too. The first thing I did as an alignment tech was to switch the two front tires side-to-side, and drive the car. If it pulled the other way, it was a tire issue. It's important to understand the difference between a pull and an off-center steering wheel. If the car goes straight when you hold the steeing wheel straight, the steeing wheel is not off-center. If the car steers itself to one side or the other when you let go of the steeing wheel, it's an alignment issue, or the tire pull I mentioned. There are two different alignment angles that can cause a car to pull to one side. One of them will also cause the steering wheel to turn a little, the other one won't, so you can't really use that as a clue. You can have a car that doesn't pull but the steering wheel is severely off-center. Also, it is possible but unrealistic to expect any car to go a half mile without drifting out of the lane a little. To travel a quarter mile on the highway without touching the steering wheel is not asking too much but it might take multiple attempts over various stretches of road.
When you let go of the steeing wheel to see if the car pulls, the test is not accurate at low speeds and on city streets because of the severe irregularities in the road surface. Do this on the highway. The right lane of roads is pitched to the right so rain water will run off. This is called "road crown" and will cause most cars to self-steer toward the ditch when you let go of the steering wheel. To reduce the effect, most alignment techs will adjust in a little left-hand pull to counter the effects of road crown. Not all roads are the same so you will have to try this in many different places. Don't be alarmed if your car drifts slightly one way or the other, but you shouldn't have to constantly be tugging on the steering wheel to keep the car going straight.
If you become familiar with the handling characteristics on specific stretches of road, you will be more likely to notice when a change occurs. A sudden change over a period of a few days suggests a tire or alignment change. A gradual change is more likely due to wear taking place in a part, or more commonly, changes in ride height of the car due to metal fatique of the springs.
The third thing to look for is tire wear. All reputable service people will take a quick peek at your tires while they're performing other service. To NOT look at them is the same as your doctor curing your illness, but not bothering to check your blood pressure. When unusual wear is observed, the mechanic will also run his hands over the tire tread to feel the wear pattern. That will tell him which angle is out of adjustment before he ever connects the alignment equipment. People often do themselves a disservice by buying new tires, then taking the car somewhere else for the alignment. We would prefer to "read" the old tires so we know which adjustments to expect to have to change.
Since they suggested an alignment for your car, they should be able to explain to you the reason by showing you the tire wear. The only other reason to do an alignment is it is necessary after replacing the rack and pinion assembly because the assembly includes some of the adjustments. I'm not convinced you need all the power steering parts replaced. Metal flakes and unusually-colored fluid aren't exactly a reason to panic. The metal flakes, I suppose, could damage rubber seals, but if you're going to pay for all those parts, why not wait for them to develop a problem first? You can plan in advance for a heart attack, but why pay for the operation before, and if, it becomes necessary?
I suspect the airplane sound you're heaing is air in the power steeing fluid. That would be introduced from installing a new pump and will go away eventually on its own. Most mechanics will drive the vehicle to purge the air, but sometimes there's nothing you can do but explain to the owner that it will take time. The microscopic bubbles take the longest to remove, and they will cause the fluid to look milky. Most of these tiny bubbles work their way out when the vehicles sits for a while. Running the engine and pump just keeps circulating them preventing them from leaving the fluid. I would stop spending money on parts for now. Drive the car for a week and I'll bet you find that you won't even notice when the noise goes away. If the buzzing noise continues after a week or so, then go back and give them the chance to correct any problems.
Monday, February 22nd, 2010 AT 7:11 AM