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.
Tell us your experiences with Monkey-designed products. Send examples to Rob Spiegel for Made by Monkeys.
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.
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.
@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!
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.
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!
In the past I have tried contacting Govt. agencies for defective products as well as services not provided. I have yet to receive any response worthy of my time. Maybe by contacting the NHTSA, I would have received a different response. I will have to keep on fighting the fight.
Without going into long details, I have only received the fast shuffle, and responses "We do admit that you have sufficient evidence to support your position, but we are unable to enforce. We suggest you contact legal representation and proceed accordingly."
After a while, you get most frustrated at banging your head against the wall and hoping that powers in place, (who are paid to watch over our individual interests), will do their job, but then refuse to assist.
As recent as last week, we received another notice from GM to have the power steering motor replaced. Amazing how just the motor was not available until GM had to issue a recall. Prior to that, the complete steering assembly needed to be replaced. But once the repair bill was on GM's $, they then (and only then) acknowledged that the issue was due to a defect in the DC motor. NO mention of the complete steering assembly, or reimbursement for those who already paid for the entire assembly replacement. No acknowledgement that they had erred previously when they advised that the entire unit needed to be replaced.
This was one of the main reasons the GM bailout was questioned. Naturally we all wanted to keep the jobs, but it defeated the natural course of "supply and demand" that is reflected by quality of goods and value.
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.
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.
This kind of nonsense has been going on for a VERY long time. For years, I had a strong preference for imports; however, every few years I would decide to give an American manufacturer a chance. In 1973, I bought my wife a Plymouth Scamp (P version of the Dodge Duster). After a year or two, it began to have strange issues with the electrical system (short battery and light bulb life, intermittent operation of various subsystems, etc.) After several trips to the dealer with no resolution, I found that the charging system wa the source of the problem. It had an alternator, with a separate voltage regulator mounted on the firewall. The firewall was painted, as was the VR box, and there was NO GROUND wire in the harness. To work, it required the ground connection to be provided by metallic contact between the VR box and the firewall/mounting bolt (ONE bolt, BTW!). As a cost reduction idea, they didn't use a star washer (or any other type of lock washer) under the bolt head. Thus, after a while and miles accumlated, the VR lost its ground connection (intermittently, of course) and started WAY over-charging the battery! I installed a star washer (OEM cost ~ 1/10 of a cent) under the head of the bolt, and had no more issues with THAT problem. I talked about this to a couple of co-workers who had owned other Chrysler products over the years (all EEs, of course) who told me that those cars ALWAYS had this kind of issue, it was well-known to Chrysler for years, but nobody would fix it! Unfortunately, this wasn't the only electrical issue; about 2 years later, we were driving down I95 in South Florida (worked for Motorola in Plantation then) when the car suffered a short in the wiring inside the steering column and caught fire!
I have an even better one, much more recent: (it's always my WIFE'S car!) a 2006 Hyundai Sonata. Shortly after we bought it (in July 2005, just after the new model came out early), I noticed a strange phenomenon: baout 50% of the time, the "Airbag disabled" tell-tale would be lit when I was driving the car with my wife in the passenger seat. Now, my wife is certainly larger than the children for whose benefit this new Federal requirement was ordained, and so she brought back the car for warranty service. They checked out the car, said they couldn't find any problem and couldn't reproduce it. This was repeated a number of times. Finally, being an EE working in the automotive industry, I got fed up with this lackadaisical response to a critical safety issue. I downloaded a copy of the FMVSS (Federal Motor Vehicle Safety Standard) that applied to air bags and seats (all 500+ pages, BTW) and waded through it to find exactly what the requirements for this "safety" feature were. It turns out that nowhere in this document was the intent of the requirement stated, nor were thee anything that I as an engineer could recognize as "real" specifications. The only item I found was a TEST PROCEDURE for verifying compliance with the (otherwise unspecified) requirement! It involved a couple of sandbags (one the wieght of the "average" child, the nother 150 lb. the represent a smallish adult), setting the front passenger seat fore-aft range to its center, and setting the seat back angle also to mid-range. If the "child" sandbag was in the seat, the airbag should be disabled; if the "adult one was, then enabled. Apparently the unfortunate Hyundai engineers designed to the TEST, not the (unspecified) actual requirement, and set the seat micro parameters so that ONLY within a very small range centered on the seat position specified in the test would the airbag be ENABLED. It gets better: finally, NTHSA ordered a full recall campaign from Hyundai. We got the notice, and brought the car in. The service manager explained that we would have to leave the car for several days; they had to remove the passenger seat assembly, and ship it to the srevice depot in California, where the ENTIRE SEAT COMPUTER assembly would be replaced. They actually had no way to reflash the micro at all, much less than via the OBDII port! They provided us a loaner (new Sonata); when we got the call that the car was fixed and ready, we went over and picked it up. Now, the airbag is disabled only about 20% of the time.....
It is not surprising that they went so very cheap as to use one bolt and no star washer. Having worked in the engine electrical department at Chrysler in that era, I can tell you that there was no concern for reliability after the first few years of vehicle ownership. A used car buyer was out of luck. A portion of this problem lay at the feet of the managers who all had cars that were maintained by inside mechanics on a daily basis, because nobody wanted to end their career by letting a boss-type experience an inconvenience with their vehicle. In addition, the purchasing department was rewarded for every cost reduction that they could come up with, which frequently included buying components that were less corrosion resistant than what the designing engineers had specified. So this was a case where the situation should really be labeled "managed by monkeys". since the assembly crew was not consulted about problems ever.
I continue to be disappointed with General Motors when it comes to design errors in safety critical systems. I own a Cadillac Deville. It is a 2001 model, so it has hydraulic power steering. After all the years of cars having power steering, one would assume that technology had been mastered, especially with GM's legacy "top of the line" automobiles. The GM design on this car is such that if the engine stalls, the power steering not only goes away, but it immediately LOCKS the steering in the last commanded position. I'm a strong guy and I couldn't steer the car when the engine died. Before I could get the car into a repair garage to diagnose random engine sensor problems that caused a complete shutdown of the engine, the stalled engine and subsequent lock of power steering put me into the wrong lane more than once. I was very lucky that I did not run over someone or hit cars in the other lane. I would be very interested to hear an explanation why such a design was allowed to make it to production.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
6 
