My girlfriend’s daughter purchased a 2005 Chevy Cobalt with 45,000 miles in 2009, per our recommendation, after we expended a considerable amount of time comparing models and reviews from all manufacturers. Three months after she bought the car, the power steering stopped working, intermittently. This got progressively worse. It’s very dangerous when you are trying to make a corner and the power steering goes out. All of a sudden, you start sliding into the oncoming lane.
I went online and found literally thousands of postings from people who experienced the same problem. This issue generally cropped up anywhere from 30,000 to 60,000 miles. I contacted Chevrolet service in Detroit and was advised that this was the first time it had heard of the problem. I told the agent there were hundreds of cases where people stated they had also contacted the factory, and hundreds more who contacted their local car dealership. All received the same reply.
These models use a DC motor and gearbox arrangement located just under the steering wheel panel to provide the power assistance. They are actuated electrically, not hydraulically, as with other models that have power steering pumps and reservoirs. The problem, Chevrolet stated, could be with the motor, the gearbox, or something else. You will have to pay a dealership to have it inspected, but either way, this is a factory item, and only the complete steering assembly is sold. You cannot buy individual parts, such as the DC motor. Chevrolet “investigated” and refused to honor the warranty on this “individual” failure. It refused to provide me an email address so I could send it links to the thousands of reported cases.
I work for an electric motor distributor, and I develop and provide training on motors to our sales force. So I am very familiar with DC motors. It seemed to me that the most plausible reason for failure was with the DC motor. I added wires to the motor connection, connected to my voltmeter, and found that the 12V DC power to the motor did not vary when the power steering failed. Therefore, the problem was not in the power to the motor. I was also able to find a point when the motor did stop working. I did more research online and found that the average cost for the complete assembly replacement was $3,500. I also found that another technician had identified the DC motor as the culprit.
After searching on eBay, I found a complete new assembly for $300. I purchased this and replaced the motor. I then disassembled the original motor and found that the brush springs were insufficient in wire diameter and turns. They did not even give the amount of force that a pen spring has. These springs push the brushes against the motor armature (transferring the DC power to the motor’s rotating shaft).
They were so small and weak that the motor brushes wore unevenly and actually caused them to bind into the brush holders. I would never have thought anyone would have considered using something so weak in such a critical component. I sanded the brushes flat, slightly stretched the springs to give additional tension, put the motor back together, and tested it. It now worked as it should. The issue is cost savings in the springs for the motor brushes -- probably a fraction of a cent, at most -- which translated into thousands of dollars for the consumer, not counting towing and rental car fees.
In 2010, Chevrolet had a recall on this problem. It would only inspect and replace any existing defects. If you paid to have the problems fixed, it offered no compensation. After five years, most of these parts would already have been replaced. I now have a spare motor and will hang on to it until she sells the car.
This entry was submitted by Rob Horton and edited by Rob Spiegel.
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Problems like this seem to permeate the manufacturing industry. A company saving a few cents or dollars on a substandard cost reduced component which affects the function of the whole system - in this case a car. I am sure whoever buys this car would be happy to spend another $2.00 to have one that is reliable.
There is a commodity in design engineering I call CS. Collectivly, some companies have it and some don't. Some engineers have it but management won't listen. Some companies have it, but have to hire outside contractors to provide CS.
We have ourselves to blame for this race to the bottom. The big-box business model is the lowest cost products, regardless of quality or service provided. The big-box business model is SUCCESSFUL; how many independent, local, small-town hardware stores are still around? The small town hardware stores arguably had better, personal service, might have had higher quality products, but the cost was higher as well.
Airlines have raced each other to the bottom as well. There's not a single airline that offers a hot meal as part of the ticket anymore. Most don't even offer hot meals! Quality of service was sacrificed at the altar of low cost.
Many people will claim they will pay higher prices for better quality, but the market proves this is not the case.
@Greg Stirling: Tempering the almighty drive to roll out low-cost products with CS engineering expertise is definitely becoming a difficult balancing act for many engineering organizations. Mr. Horton is lucky that his background and skill set let him attack the steering problems head-on--most average car buyers are not as fortunate. I say take to the Twittersphere and spread the tale of caution and the potential fix--I'd be hardpressed to think Chevy won't be listening!
The idea of electric assist power steering is scary to me.Last week, the battery on my RAV4 lost one cell.My wife called and I gave her a jump.I then drove the car to work, planning on replacing the battery after work.What I found was, as long as the revs on the engine were up, all was fine.However, at one point, as I was exiting the freeway, the revs dropped and apparently the voltage to the power steering dropped. When the power steering kicked out, I almost ran off the exit ramp.Very dangerous. This will at some point cause a serious accident.
There is another possible reason the original brush springs were low tension. The following is speculation--I have no direct involvement with the electric power steering on this car. Steering systems are very sensitive to friction, even small amounts of friction can make steering unpleasant--for example, not return promptly to center when released. Adding a gear drive and motor to the steering column adds new sources of friction/stiction in the most sensitive place--close to the steering wheel. I'll speculate that an attempt (perhaps misguided, in terms of the service history) was made to reduce the motor brush friction to the bare minimum in an effort to control the overall system friction.
If friction was an original engineering concern, perhaps a brushless motor, and/or a direct drive motor (low RPM torque motor) would have been a better solution?
While almost every article that appears in this column relates to poor "engineering", I would suggest that MORE people who experience these situations take the time to contact the various gov't oversite agencies to formally complain. That is the ONLY way that manufacturers and/or distributors are going to get the message. This is especially true for the automotive industry. This article is a prime example for such an occurrence. The family involved should have NOT wasted their efforts to contact CHEVROLET, instead they should have contacted the NHTSA, highlighted all the facts, and then waited for a response. IF, in fact, an internet search showed several thousand entries from other owners experiencing the same malfunction, that would have been sufficient "ammunition" to generate interest at the agency. Contacting Consumer Protection Agencies in local state gov'ts may also offer some relief, since the dealership which sold the vehicle may have to answer to a gov't agent, a burden they'd rather avoid!
Inferior quality is one issue. Even worse is Chevy's apparant willingness to deny the problem and take care of their customers. This is one reason so many of their customers now buy Toyotas. I'm sure it's expensive to correct this problem. I'm inclined to think that they have gambled that it's cheaper to loose customers and or fight it in court when the time comes.
As it happens, I'm in the market for a new vehicle. I was considering a new small Chevy as a town car. This article has convinced me that this is a bad idea.
Where did this person do his research at? The Cobalt has never made any recommended lists that I know of. Did he forget GM went bankrupt. Thank God, 180,000 trouble free miles ago, I bought a Honda. If he had researched the Civic or Accord we would not be having this discussion. Oh, by the way my Accord was build in Marysville Ohio.
Amazing stories. When I heard of electric power assist years ago, I thought "great idea - no more fluid leaks, hoses, engine-driven belts", but looks like the implementation fell short. I second the brushless DC motors idea. Seems wise for a motor in continual use where brushes would wear significantly, though costs are higher.
Where do they come up with $3500 for a replacement assembly, and no individual parts sold? Can GM spell "extortion"? Do you think their field testing predicted brushes would fail every 45K miles? I drive several 60's cars and parts are so cheap I keep a backup for most everything on the shelf.
Re safety, I assume they designed the electric assist with something like an over-running clutch or slip clutch (aka garage door opener). Otherwise, a jammed motor or gear could lock up the steering, which is the worst thing. Even if one only loses the assist, that is enough to cause some people to scream and just let go of the wheel (my wife). In traditional hydraulic systems, that happens whenever the engine cuts off, whereas electric assist continues as long as the battery is good, which seems more reliable.
I lost the assist in a hydraulic system recently when the plastic pulley cracked, which also drained the battery (alternator slipped on serpentine belt). I only noticed when I exited the freeway, with strong effort on the wheel. The problem is you only notice the lost assist when you need it most.
Compliments to Mr. Horton for tracking down the problem. Chevrolet's response, as explained here, is shameful, especially considering the potentially dangerous effects of this problem. I also agree with "Old Curmudgeon" below, who suggests that the victims of this kind of shoddy design should make a point of contacting appropriate government agencies.
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