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Car Window Repair
Project Background

My car was built in 2001, and while it still functions well, it has had its fair share of mechanical issues. Some such issues have required a professional touch, but others I like to take into my own hands and see if I can learn something while saving money without risking safety, of course. For reasons unknown, the manufacturer of the mechanism tasked with controlling the window’s ability to roll up and down made a few poor design choices, and the mechanism seem to be engineered to fail. Within the same year, in 2017 and 2018, my back and then front passenger window mechanisms failed, both in the same way. I wouldn’t have been as unhappy about these failures as I was had the windows stayed up when the culprit part snapped, but they fell into the door, leaving the inside of my car exposed to the elements. Rather than spend hundreds of dollars to have someone replace everything, I opted to repair the car myself.

The first time that it occurred was at the end of the summer. I tore down the car’s back-right door into its components to figure out what had failed and noticed that the piece responsible for fastening the regulator cable to the window was made from injection-molded plastic and had broken on one side. The weak plastic supports designed to hold the ends of the cable in place are laughably flimsy, so it’s a wonder how they hadn’t broken from excess stress while driving over a bump at some point in the past two decades.

This issue occurred twice in the exact same manner on two different doors. Usually, one would pay a few hundred dollars to have the mechanism replaced, however my stepdad was able to mail to me a replacement unit which I easily installed the first time around. The second time that it happened, though, I opted to repair the broken piece myself instead of paying for the replacement mechanism. Using my basic welding and grinding skill, I fashioned a steel version of the plastic hook that had failed and was able to weld it in place. I have had no issues with either window since the repairs, so they seem to have been successful. Events like these remind me how grateful I am for the ability to make home repairs.

Detailed Description

I discovered the first broken window mechanism in September of 2017. My first reaction was to pause everything else that I had planned for the day and ensure that my window was not open as a public invitation to break into my car. I spent a few hours disassembling the door and window mechanism, memorizing the locations of parts as well as figuring out where pieces that had fallen out of place were supposed to go, and their functions. Upon finding the broken plastic piece meant to hold the regulator cable, I began thinking of ways to permanently fix or replace it. Immediately, welding came to mind.

I planned to mimic the structure of the original plastic hook using a small piece of steel and weld it into the location millimeters in front of the broken plastic hook, which was made from thick galvanized steel, an easy surface to weld to. After mentioning this idea to my mom, whom at the time was the owner of the car, I was told that since there was no easy way to acquire an intact replacement plastic piece, we would instead replace the entire mechanism.

Apparently, replacing the whole mechanism is how that kind of issue is solved in the professional world, which I don’t personally like very much. I believe that, especially in vehicles, no parts should be engineered to fail, unless designed to fail before so as to indicate impending catastrophic failure of a safety-compromising part. The failure of this plastic piece did nothing in this case except force me to repair or replace the mechanism. And because in the professional world the entire mechanism must be replaced, your average consumer would have effectively no choice but to spend money on such a repair, being charged for the replacement of working parts as well as the broken ones.

If this mechanism was not engineered to fail, then it was a horrible design flaw. The choice to use plastic in this load-bearing part instead of metal, and to give the hook such flimsy, thin walls was a mistake. Since the final decision changed from me replacing the broken piece with a metal version to ordering a replacement mechanism instead, I had to find a way to prop the window open to seal the car while I waited for the replacement section. I attempted to use a few nearby materials to support the window from within the door frame, and eventually found a piece of Styrofoam sturdy enough and at the correct height to hold the window closed.

Within a few days, the mechanism arrived in the mail, and the replacement process was fairly straightforward, requiring only large fasteners like bolts and machine screws to be removed and then added back after the new mechanism was in place. While it was easy to perform, it was still time-consuming, and I made the annoying mistake of leaving the door open the entire time, causing all of the lights inside the car to remain on for the entire duration of the repair. At the end of the replacement, to my disappointment, the engine wouldn’t turn over. I had no other cars nearby to jump my own from, so I had to improvise and pulled two 18-amp-hour 12-volt batteries from my motor bike project, which hadn’t been charged in over a year. To my surprise, when I had both batteries running in parallel with the car battery, the engine was able to turn over and begin charging the car battery via the alternator.

On the 4th of July in 2018, the same mechanical failure occurred, but this time, my front passenger window failed. I wasn’t fond of the idea of purchasing the replacement regulator mechanism, and my name was on the car’s title this time around, so I settled on testing out my welding modification idea. At the time, I was working for the university and couldn’t find much time during the day to perform the repair, so I pulled up the window and held it in place by wrapping the regulator cable around the doorframe. This worked fine for a time, as I rarely use the passenger window for anything, and it kept a good enough seal to prevent rain from getting in.

When I finally found the time in September, on what happened to be my last day working for the ITS help desk at the university because I had graduated, it took only a few hours to prepare the door and get the window back in working order. The window was easy enough to separate from the track that it rides on, exposing the metal frame that I needed to weld to. The welder that I built operates on 240 volts AC, so I found two out-of-phase outlets in my apartment which would supply it with 240 volts. Using a bench grinder and Dremel, I shaped a small piece of weldable steel into a hook with a slit down its center to accept and lock the regulator cable in place.

Arc welding is messy but is capable of producing deeply penetrating welds, so it only took a few seconds to solidly attach the hook to the window after brushing away the thin galvanized coating. I had to check the regulator cable for damage that could have been caused if any sections of the cable got smashed within the pulley which was a problem that I had when the first window broke. Luckily, the second time around, the cable was only slightly frayed, and the small amount of damage to the pulley track was easy enough to file away.

All that remained was to rewrap the cable around the pulley and mount the motor and window assemblies back onto the door frame before testing that everything worked properly and replacing the internal door cover. Nothing went wrong when I tested the window mechanism, and the welds held firm, so I closed up the door frame and packed up my tools. In this case, I only saved myself around 100 dollars. Nevertheless, having the ability to solve these problems on my own with my tools is a skill that I greatly appreciate, and I enjoy fixing my problems with my own resources far more than outsourcing them. It’s the best way for me to practice troubleshooting and operating tools and gives me ample opportunities to learn from my mistakes.

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