Great real-world example showcasing the need for engineering teams to seriously address Design Failure Mode Effects Analysis--a process that perhaps isn't as robust as it should be on many a development effort. You were lucky that you had enough ingenuity and engineering smarts to troubleshoot and handle this problem on your own. Most people wouldn't be so lucky.
It is interesting that in the automotive world that this type of FMEA is not done more completely. As Beth mentions, quite charitably, the process was not as "robust" as it should be.
Some of your examples ring very familar, although most of my early experience was with small British sports cars. My first car had a leak on one side of the oil pan (the passenger side). That side had no rust. The other side had rusted through and a previous owner had used some old road signs to replace the rusted out floor pans. As this was under the carpet, I didn't see it at first.
I do notice cars I have bought in the last decade or so have much better corrosion resistance, and I live further north where they use lots more salt.
Ironically my experience with automotive floor pan rust was usually from the inside out. either the windshield frame would rust until it leaked or window seals would leak.
Cars with carpeting would get wet carpet then dry-out. Cars with rubber matting would get wet and stay wet until the floor pan rusted out (from the inside as I said with my experience).
And yes, newer cars seem to do much better with rust-proofing. I don't know if it's from the body design or processing with an immersion pool of rust proofing primer or zinc/cold galvanize, but most cars have better rust performance since the late 1970's.
First, the automakers have or at least had a time limit on all recalls that were not emissions or major safety recalls. If you purchased and registered a car after the notification period had expired, the automaker was under no obligation to send you a recall notice.
Dealers might only check the recall status if the work being performed involved the same area of the car as the recall.
Now with the fully computerized systems you have a much greater chance of being informed of every recall related to your car.
Second, while some chemicals can hasten rubber failure, I believe you will find that nearly every rubber motor mount will fail over time. The rubber dries out and just plain rots.
Interestingly, my 87 and 94 Taurus'es that I owned past 300,000 miles each were never recalled for subframe mounts. I did have to have 2 of the engine mounts changed out on my 87 though.
We owned an 86 Buick where the subframe itself rusted out. I went to jack it up to check the front brakes one day and we had a loud snap with a large cloud of rust around the jack. Inspecting the subframe at the other mounts, I decided it was not safe to drive the car. The only good repair option there would have been to replace the entire subframe. Got to love road salt.
I worked for a large Tier I auto supplier working on driveline components. I won't mention the company name since I will mention they screwed me out of my severance. At any rate, DFMEA's were a joke. The DFMEA was just another check box in the development plan and usually considered of low importance compared to getting the testing on the latest LCC sourced parts completed. Thus the DFMEA was usually done last in the design process by whoever drew the short straw (DFMEA's were considered boring by most of us, and, because they were done AFTER design, rather pointless). You usually took a DFMEA for a similar product or the previous version of the product, made some tweaks here and there, updated as much you could stand or had time for, got some signatures, filed it away in a book and on the server, and checked the box on the gantt chart. The product got validated and put into production on time, you the lowly engineer got to keep your job (for now), project managers got gold stars, executives got bonuses, and the product wasn't as good as it could have been. Pardon my cynicism, but that was the process as I saw it.
As a kid in the '80's, we had a Chevy Citation which had its share of issues, but the main thing we saw was that after the first few years, there was a spot in the center bottom panel of the driver's side door that would rust out every year before the annual inspection requiring a fiberglass patch. The next year, the patch would be gone and you would need a bigger patch. In watching the car run, there was just enough room beneath the front mud flap for a small stream of rock salt to hit the exact location of the rust spot. The solution was longer mud flaps for our car, but I remember seeing a lot of similar Citations with the same rust spot.
I drove a car with that engine for six years and never had problems with it -- maybe I didn't own it long enough. I liked the engine. I chose it instead of a 3.8-litter because I heard the 3.8 had head gasket problems.
I too heard that the higher performance 3.8 liter engine had some reliability issues.
I have VERY good engine experience with a 1985 Taurus Company car and this 1987 Taurus Station Wagion that I later bought BOTH with the 3.0 liter engine. I drove the Station wagon until it had 156,000 miles and the enginer was still running well when I traded it in. The transmission was on it's last legs at that point with poor shifting and sometimes slipping.
I would buy a car with that 3.0 Liter engine again in a heartbeat. It looked good, ran smoothly, had good performance, was low maintenance, was easy to maintain, got 22-26 mpg and was reliable. What's not to like?
i've worked on these type of parts for 20+ years and the requirements for corrosion have evolved due to technological advances in surface chemistry, litigation from accidents due to corrosion, and overall advancements in customer expectations of quality.
i'm sure the dfmea process was done and the vehicle level testing was done by ford, but sometimes this type of corrosion doesn't show up until some time has elapsed. hence the galvanized washers added as a recall.
i think you will find that designs over the last 5-10 years are much more robust due to the lessons learned on these previous models
i'm glad you were not driving when the mounts failed.
From a Design perspective, I for one would be very interested in more detail about the "technological advances in surface chemistry" you mentioned.
Additionally, as an automotive and motorcycle enthusist, I would like to use some of that knowledge for more robust restorations and upgrades on my personal projects.
I feel that the galvanized washer upgrade by Ford was a simple and very good technical solution to that particular problem. I was disappointed about the poor implimentation diligence of this recall on ALL the affected vehicles; since, this was clearly a significantly dangerous potential failure to the running gear. I was not informed about it prior to the failure, and the video I found on the internet of a man changing the rubber bushing on the same model car also did not have the recall upgrade installed. I would venture to say that likely MANY of these vehicles never had the upgrade installed. A great upgrade only works to the extent that it is implemented.
david - the best steel pretreatment i could recommend under paint would be microcrystalline zinc phosphate. it uses a calcium modified chemistry that results in small crystal sizes and lower build weights (thickness). this allows for good paint adhesion and underpaint corrosion protection but also has good flexibility to prevent chips or dents from propogating. edges are better protected as well. some of the new primers are designed to work with zinc phosphate and can enhance the advantages.
new cars are typically dipped before painting. you may have to find a metal prep shop that has tanks large enough to do your individual restoration parts.
Taurus station wagons were well-known for having transmission problems which kicked in at fairly low mileage. You just had a more catastrophic version of this, via the entire transmission (and engine) falling out of the car...
Even when many automatic transmissions are prone to failure by diverse mechanisms, one of them being using a too small desing for the weight/power of the car, one thing I have seen in common is the very low maintenance they receive. This could be because of some myths surrounding them, like the one that says that if you neglected to change the Fluid for a long time, an ATF change will make the transmission fail inmediately, or start a huge spill... there is a little bit of truth in this belief, but one thing is that an abused and neglected auto transmission that has formed a lot of sludge inside will probably start to leak profusely because of long degraded seals and gaskets (the sludge was actually helping to seal), an another thing is to delay a proper fluid change because of the false belief that ATF is "eternal" or "for the life of the vehicle".
And talking about the 'proper' way to change the fluid, is to remember that most transmissions do not have means to drain all the old ATF. This means that the usual "Quick-and-dirty" Oil Change places will only drop down the transmission pan, which removes only the old ATF in the pan, frequently less than half the total contents of ATF of the whole transmission. The Torque Converter can hold anything from 50% to more than 60% of the fluid, but in most cars it lacks any plug to remove the trapped fluid.
The best way to perform a proper and complete ATF change, is to first remove the transmission pan in order to change the trasmission filter. Then the pan is cleaned, reinstalled and sealed with a good quality RTV, the same quantity of ATF that the pan was holding is replaced with new ATF. THEN, the hoses going to the transmission oil cooler are disconnected and routed to a large translucent container, previously marked in quarts with a permanent marker. Prepare a small table to place several extra quarts of new ATF, already opened and ready to be dumped into the level stick tube thru a large funnel. Now, start the engine and put the transmission into drive (the car has to be properly blocked and parking brake applied). As soon as the engine starts, the transmission hydraulic pump will start to move the fluid and discharge it thru one of the hoses. You have to keep pouring the new fluid as the old one is being pumped out, that's the reason for marking the receiving container, so that the proper level of fluid is maintained since it is important to avoid ovefilling or running too low. It helps to cut a short (4") lenght of transparent tubing and to use a lenght of transparent vinyl tubing in order to actually see the old fluid as it is discharged into the container. By putting a white piece of cardboard illuminated with a 100 watt light behind the tubing along with the short lenght filled with new fluid, it is very easy to see the slightest change in color, which will turn from a dark brick red color to the transparent light cherry red of the new ATF. In my car, which holds a total of 9 quarts of ATF, after putting the initial 4 quarts into the pan, an additional 9 quarts were circulated in order to completely flush the whole transmission. From quart number 8 the color was almost as transparent as the color of the new fluid, by quart number 12 the color was practically undistinguishable from the new fluid. By contrast, the color of the old fluid in the pan was still red, but very dark.
I forgot to say, there is a small magnet on the bottom of the pan, which will almost certainly look as a sea urchin, full of spines formed by metallic dust from the wear of the clutches and other parts. A teaspoon full of metallic particles is usual after several tens of thousand miles of driving. It also helps to have an assistant to put the transmission tru all the positions during the flush, Reverse, drive and every other, to help in washing out the old fluid. Some mechanics even add a small bottle of "Oil System Cleaner" like the one used to clean the engine, but it is only necessary if the ATF was not changed in a very long time.
By performing a complete ATF flush and filter replacement every 25.000 miles, the transmission will last for the life of the vehicle, often more than 100.000 miles without failure. Take note that Chrysler Vehicles use and require a different kind of ATF (called "ATF+4) and not the more common "Dexron II or Mercon".
In late 1975, I purchased a new TOYOTA CELICA "Fastback". To those who remember, it was very much akin to the original MUSTANG fastback. At any rate, this vehicle was garage-kept, 95% of the time when not in use, since we lived in one of the northern states, prevalent to winter storms, snow, sleet, rain. On about the 3rd year of ownership, I noticed the large rubber gasket which sealed the rear hatch was loose when I opened the door. So, I attempted to place it back onto the flange lips. (The flange lips were created from the inner sheetmetal & outer sheetmetal panels, and spotwelded along their length for strength & bonding.) In doing so, I discovered that there was no flange present at all. So, I continued to remove more of the gasket, until I had most of it in my hand. When observing the gasket more closely, in the cavity of the gasket was a very long coil spring which was designed to rub up against the flange, providing the necessary grabbing force. Additionally, this cavity was full of rust! That was the turning point for us. Since the flange was non-existent due to total corrosion failure, I made a "sneaky" repair, undetectable to the naked eye, and traded it in on a 1980 DATSUN 200SX, a fun car to drive, which I drove for 4 trouble-free years before realizing that it would be best to add a 4-wheel-drive vehicle to the stable. And, so we sold the DATSUN to the next-door neighbor's oldest son, and bought a 1984 FORD BRONCO II. ANOTHER GREAT vehicle!!!!
I have experience destructive corrosion on a number of vehicles and it is evident that every year the auto manufacturers use a new/different steel alloy to enhance ductability, increase the cycle life of the dies, improve paint adhesion; some years Ford has a winner for rust susceptability, some years they lose. Most suspension components are uncoated and apparently not designed to outlast the painted metal elsewhere on the car. Northern states have started using a liquid substance that greatly lowers the freezing point of water in much smaller concentrations. This substance cannot be allowed to remain on uncoated metal, it is much more active than Sodium or Calcium chloride. If you want to keep your $20-30K automobile for 200,000 miles, wash it every other week during winter. It is small insurance. The rule of thumb for cars in the 40's through 60's was to wash weekly, wax every 4-6 months, re-paint every 4-5 years, do an engine "freshen" every 50K miles and you could expect your car to last 25 years. Today most people never wax, never wash the car, never re-paint, are lucky to do an oil-change yearly, and expect their cars to last 200,000 miles. Dealers haven't helped by charging $300 or more for a 10,000 mile service, $750 for a 15,000 mile!
I don't know why, but the 1976 TOYOTA CELICA that we owned was never brought to either a ZIEBART or RUSTY JONES facility for their added protective coating. All the other vehicles we owned from the 1960s through the 1980s were all protected, and none of them ever experienced any rust-through problems. But, that TOYOTA was not an exceptionally good car in many other regards, so trading it in for a DATSUN was not an unhappy event.
The "rust-through" problem beacame so pronounced in that era that AMERICAN MOTORS offered ZIEBART-protection as a factory-installed process. Wonder if that's why AM went out of business?
This reminds me of my own nightmare with an earlier Nissan Sentra model some 20 years ago. I was pretty broke, so could not afford expensive car repairs. Apparently, a transmission fluid leak was slowly destroying first one, and then two of my four engine mount gaskets. For reasons I still can't understand, my mechanic decided to interpret my "I can't afford expensive car repairs so whatever can wait should" statement to mean these, also. But he also didn't tell me about the problem! I discovered it when I moved to Northern California, got a new mechanic, and asked why there was this vibration at 65 mph. Sheesh.
Older cars, particularily with even minor lubricating fluid leaks are known for failed rubber on the motor mounts. There was one particularly dramatic example of this I recall.
In college, I was driving my parent's old 1964 Oldsmobile Vista Cruiser Station Wagon with 140,000 miles on it. In response to some friends joking and reving their engine, I held my foot on the brake and reved my engine back. The unexpected result was the car rocked violently and the upper radiator hose failed. I pulled into a parking lot in the college town. The hose had failed from the V-belt rubbing a hole into it, but the V-belt was OVER 3" away from the hose. I scratched my head until I reproduced the power-braking with the hood open in that parking lot and saw the torque radically lifted the big V8 up out of it's already failed engine mount. (Good that it didn't smash things up trying to flip-itself-over in the engine compartment.)
I walked to the nearby auto parts store, replaced the hose, bought 2 replacement engine mounts, (if one failed both were probably due for replacement) and gently drove the car home to replace the engine mounts. When I jacked the engine up to replace both engine mounts, I saw that the third mount on the transmission was also failed and gaping apart. The engine had just been sitting in the car without any attachments, except hoses and the throttle linkage! I replaced both engine mounts AND the transmission mount.
Examination of these failed surfaces showed they had failed and were just rubbing against each other FOR A LONG TIME. I apologized to my parents for my hot-rodding behavior (busted), even if just in fun, paid for the parts out of MY pocket, and completed the repairs. My parents were pretty cool about this, and didn't get upset about my "hot-rodding, show-off behavior" in their car. (That old Oldsmobile, with the factory higher performance engine that ran on 97+ octane gasoline, was pretty powerful and fast in a straight line.)
Thanks for your story, David. The Northern California mechanic who told me about the 2 destroyed engine mount gaskets looked at my like I was crazy for driving it like that for so long. This was the first time I'd taken my car to him, and it was for a once over checkup. When he explained the situation, I must have turned pretty pale, and assured him I was not in the habit of driving my car in such a dangerous condition. Maybe he also thought I'd been hot-rodding it, although that was pretty unlikely by that time in my life. I can say I've since never taken any unusual car sounds for granted, especially those that occur at 65 mph.
In most cases, (as in my parent's 1964 Oldsmobile) I believe the engine mounts usually fail due to petroleum products (usually engine oil, or power steering fluid leaks) deteriorating/weakening the bonded rubber vibration isolation engine mounts. "Hot rodding" can be the straw-that-broke-the-camels-back. Alternatively of course, with a very stout engine being raced hard, even a new mount can be broken (also a frame can be bent by a racing engine without sub-frame connectors and a robust roll-cage.).
In the case of the Oldsmobile, I believe (based upon examination of the worn failure surface) the "hot rodding" just identified a problem that was already there for some time, but undetected. I do not feel I broke their mounts, but the identification of the problem also pointed-out that I was "hot-rodding". Even though this action was somewhat mild, it was contrary to their boundaries.
As a point of interest, to address the root cause on my parent's car, I also replaced the leaking power steering hoses, and valve cover gaskets, to get rid of all the fluid leaks. That particular car was still going strong at 199,000 miles when I sold it to a friend. He still had no problems with it by 230,000 miles when I last saw him in 1984!
This was a well known issue with Chevrolet V8s a long time back.
Along with my 1940 Chevy street rod, I have a 69 chevy pickup. The pickup has a cable on the driver's side of the engine - it bolts to the exhaust manifold, runs through a hook in the frame and back up to the mainfold. It's only needed on the driver's side because the engine torque lifts the driver's side and compresses the passenger side. The angle of the mounts limits the 'spin' factor and act as pivot points.
Aftermarket motor mounts have interlocking steel plates that eliminate this problem.
From what I read about the 1971 National Highway Traffic Safety Administration (NHTSA) report to GM, the drivers side cable you mentioned may have been a dealer installed recall fix to the 1969 Chevrolet V8 engine mount prior to the "Safety Mounts" from the factory with interlocking steel plates starting around 1972.
Another example: The rear mount on the flat 6 Corvairs had interlocking steel backup structure from the start. When these rubber parts failed the T steel would drop onto the sides of the steel channel slot. This would then transmit much more engine and road vibration to the passengers until replaced, but without the steel backup the engine would have fallen onto the road. To check, we would lay a straight edge across the rear mount. It should rest on the center steel T without touching the mount side rails. If it touches the side rails the rubber had failed and the center T has dropped. I didn't use this information much because my last Corvair had a 327 cid SB Chevy V8 in a mid-engine configuration, but this was relevant for several friends with Corvair engines, (e.g. - street Corvair with modified 60 over 172 cid, big valve heads, big turbo and water injection putting-out 250+ hp, and the most radical one was a drag-track VW bug "Snoopy" with a Corvair engine custom twin-turbo putting-out over 600 dyno-horsepower at 12,000 rpm and around 30 psi boost for short time periods between blowing it or the transmission up).
The fluid that destroyed my engine mount gaskets was transmission oil, so that fits. I made sure my new mechanic fixed the hose leaks that had caused the problem, and also checked all other hoses and gaskets. I've been pretty proactive about doing so on all my cars since then.
Back when I worked at Chrysler they solved the motor mount failure problem by creating a motor mount that put the rubber in a hole in a support frame, so that if the rubber failed the engine was still trapped, since the two mount sections were interlocked. I think that they did it to protect the radiator in minor collisions, but it seemed like a very good idea at the time. And it would certainly aviod a disaster if the rubber failed completely.
As for the engine and trans, along with the whole front suspension being on a subframe, GM has done that on a few vehicles, probably others as well, because it does allow better isolation from the road noise, and it makes building the car much simpler, and therefore much cheaper. Of course, when the engine assembly does come unglued it is a very big deal, as you discovered in the driveway.
Of course the salt damage from road salt here in Michigan is usually far worse than the military salt spray test, mostly because our roads are far saltier than any ocean could ever be. And nobody will admit that a few tons of salt per mile every year constitutes pollution.
In the mid-1970's I built-up a V8 Chevy muscle car and Chevrolet had recently come out with "safety mounts" that had interlocking steel T and slot features to limit travel even when the rubber failed. This was popular with performance oriented applications; although, serious racers also went to either a back-up movement limiter (chain or steel cables), or else solid steel mounts (which transmitted unacceptable engine vibration for all but the most hard-core race-only cars, even rattling your vision).
What I only learned recently was that this "Safety Motor Mount" was precipitated by an investigation in 1971 of 127 Chevrolet motor mount failures resulting in 63 accidents and a few fatalities. The result of this National Highway Safety Transportation Board investigation was the motor mount redesign, and a recall where a steel limiting cable was installed (presumably cheaper than retrofitting new motor mounts). What made this type of failure a greater problem leading to the investigation was the cascading problems from the motor mount failures. The lifting engine pulled the throttle linkage "on" further lifting the engine even more. The engine movement also locked-up the transmission linkage preventing a shift into neutral, and the engine movement sometimes ripped loose hoses to the power brakes and power steering making steering and braking MUCH more difficult. Hmmmm, sounds like an accident waiting to happen similar to the more recent drive by wire Toyota throttle issues.
I guess Chrysler anticipated this problem better, or experienced it sooner with their monster 429 Hemis.
I know the GM and Ford sub-frame module constructions, such as in the Ford Taurus and GM X body cars, did allow for better road vibration isolation in a unibody car construction as well as provided a convenient module for efficient assembly. I don't think the concept is flawed, but it does need to executed properly, and reliably, or things can become very unglued in an ugly way.
The National Highway Traffic Safety Administration (NHTSA) Case IR 162 correspondance with GM between December 1970 and January 1971 indicated 172 reports of failed motor mounts, with 63 accidents and 18 injuries. There were NO reported fatalities.
I apologize for my misinformation from my inaccurate memory of the report.
It's both astonishing and sad that important automotive support structures such as body, frame, and engine mounts should be failure-prone in such numbers. Because product releases are so cost- and time-driven, manufacturers will start fishing before the bait was cut. Whatever the reason, to the customer experiencing failures it appears to be another example of "planned obsolescence," that is, the owner will have bought a new car before the failures become daily occurrences. I learned the hard way that motor mount failures can result from failure of the bonding between the rubber vibration isolation biscuit found between the engine mounting bracket and the frame mounting bracket. I had such an experience that now seems humorous, but which nearly resulted in the engine falling out of my van. You might be interested in the details of that calamity which was shown in a Design News article, http://www.designnews.com/author.asp?section_id=1386&doc_id=223529.
Good points, Myronb. There are a whole host of problems that plague a car when it outlives its expected lifetime. While planned obsolescence may have been real during the mid 20th Century, it's understandable that car makers didn't expect their products to still be on the road decades later. But indeed, that certainly happened with the T-Bird and Mustang.
It was in the seventies, probably around 1974, although it may have been in development for a while by then. I think that it may have made the engine drop in a bit easier as well, but I can't vouche for that.
The 1970s were rough years for the automotive industry. The workers on the line were an angry bunch. There was plenty of worker sabotage going on. Not a happy time in Detroit.
At the time, I worked for Celanese Coatings. They produced much of the paint for Chrysler. In the lab, we tested paint against multiple environments. The salt spray was the worst. At the time there was no way to protect paint against salt. Cars in Detroit started to rot through the floorboards after five or six years.
I lived in Maryland during the early 1980's. All cars tended to have rust problems after a few years, due to the salt used on the winter roads. The Honda cars seem to be the worst, frequently with rust through the body side-panels. My 1975 Chevrolet Monza had its fair share of rust around the rear wheel wells.
I now live in Southern California, enjoy the wonderful weather. My 13-year old 1998 Chevrolet Camaro Z28 looks just about brand new underneath...not one spec of rust.It's rare to see rust on any car in SoCal, even close to the Pacific (salty air).
I understand about rust, Rick, having grown up on the salty winter roads of Michigan. When I moved to New Mexico -- with absolutely no rust -- I met a guy who made his living by purchasing old cars (1950s, early 1960s) in pristine condition and driving them to Michigan where he sold them to collectors who couldn't find classics like the '55 Checy in perfect condition.
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