Dual Air Bags

 

Back in the 1980s and 1990s, cars did not come standard with 28+ air bags like they do now. Federal regulations required that all cars manufactured in the 1983 model year and later have a “passive restraint” system for the driver. Sometimes this was an airbag and sometimes this was one of those “mad mouse” seatbelts that automatically came up the side of the window and over the driver’s shoulder. The federal regs however had no love for the passenger, so when a car manufacturer was feeling generous, they would advertise that their car had “Dual Airbags.”

This expression became part of the American lexicon for a good 15 years. During the Clinton presidency, there was a bumper sticker with a picture of Bill and Hillary annotated with the “Dual Airbags” label. Regardless of your political ideology, it was a funny sticker.

Of course I am not writing about airbags today,
at least not those I have mentioned above.

 

I drive something the auto industry calls a “Sport Crossover.” Growing up, we would have called it a station wagon. It is low like a sedan, long like a minivan, it has three rows of seats and all-wheel drive; all things useful to a family of six in Rochester, NY.

The last several winters have been particularly harsh. In Rochester, we had lots of snow, and several stretches of very cold temperatures. Cars do funny things in extreme conditions and what my car did was funny indeed.

One day I came out of my office and as I approached my car from the back it looked like it was tipping to the left. It was one of those wicked cold days. As I got closer I could see that something really was out of whack. Using the strap on my bag I measured the difference in distance between the wheel arch and the tire on both sides. The right side was a solid 5 inches higher than the left. No matter the cause, this was not good.

CarTip

I don’t know if my car is a democrat or a republican, but for a while it was definitely leaning left.

 

I drove home watching for differences in how the car handled, but it seemed fine. If I had broken a spring or a shock absorber on the left side, the car certainly would not be steering straight or handling bumps in the road normally. The best I could figure was that in the extreme cold, a chunk of ice was caught up in my right rear suspension.

An hour later I had to drive about forty-five minutes away to pick up my daughter from a ski camp. So, before heading out I ran the car through a car wash and then drove down a street that has several speed bumps. I figured giving the underside of the car a hot water bath and a good jostle would shake loose anything that didn’t belong.

I drove the 90 minute round-trip to pick up my daughter, and after pulling into the garage, I walked around back to have a look at the car; it was perfectly level.

Problem solved right? Wrong!

 

Four days later I came out of my office again to find the very same problem, but here’s the weird part… I had been watching the car closely and I knew for sure that it was perfectly level 9 hours earlier when I had parked it in the morning. Something was happening while the car sat idle in the parking lot. Hmmmm.

As I always do in these situations, I hopped on the Internet to see if someone else had ever had this problem. Everything I found kept referring to problems with air suspensions and I knew for certain that I had not chosen to pay for this option on the car. I did not have an air suspension, so I forged ahead.

After about another hour of research I discovered two things:

  1. The air suspension option actually gets you air suspension on all four wheels, but all models of my car have it in the rear, so I do have an air suspension or at least half of one anyway
  2. Based on all of the conversations in the forums, this problem is common, but there is no consensus on the best solution

After a few days of searching and phone calls my options were as follows:

  1. Have dealer replace rear air springs – $3,000
  2. Have independent garage replace rear air springs – $1,800
  3. Replace rear air springs myself with 3rd party parts – $500
  4. Keep troubleshooting since many of the people in the forums who had the same problem expressed frustration with spending the money to replace the springs only to have the problem not go away.
My sketch of the air suspension system.

My sketch of the air suspension system.

 

The way the system works is actually pretty neat. There are height sensors at each rear wheel. When you toss five bags of concrete into the back, or when two adults climb into the third row, the rear sags a bit and the height sensors tell the pump and the control valve to add air pressure to the springs (which are basically high-tech balloons or ‘air bags’). When the extra weight is removed, the sensors tell the system to let some air out. I also learned that when the car gets up to highway speed for more then a few minutes, the car lowers itself for better aerodynamics and gas mileage – pretty slick.

The bottom line was I had a leak and I had to find it.

 

You may recall from my post about cables, that when troubleshooting electronics, it is almost always the cable. Well, in plumbing I have learned that the problem almost always lies in the connections. Over the course of about three weeks I played with draining the system of air pressure and one by one checking all the connections where air lines met components.

I tried using soapy water to find the leak, but it was so damn cold the bubbles kept freezing.

The lines that run between the control valve and the springs are plastic and connected with compression fittings. Whenever you replace a compression fitting, you need to remove all the parts, cut off the end of the plastic tubing and put everything back together to “compress” a fresh piece of tubing.

A compression fitting on plastic tubing.

A compression fitting on plastic tubing.

 

I never even got to the connections at the springs. After disassembling and reassembling the connections at the control valve the problem was solved. The car has been level and steady now for almost two months.

I recognize that my comfort level with popping the hood or jacking up the car is greater than most, but the simple lesson here is that taking the time to understand the whole system makes all the difference. If I had taken the car to my independent garage and asked them to spend a shop hour ($80) to look for leaks they would have found it, did what I did and I it would have cost me $80, not $1,800.

Take the time to get to know your stuff. The last thing you want is someone putting your picture on a bumper sticker and calling you an airbag.

 

Copyright © 2014 - Stephen S. Nazarian - All rights reserved - Dual Air Bags

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4 thoughts on “Dual Air Bags

    • Steve, I think your comfort level with taking apart and putting anything back together is much greater than the vast majority of ours, especially when it involves safety of our family members. But, I think you were just born with raw curiosity and nerve…as evidenced by your post about taking apart the bicycle braking system. It all started very early on.

  • I just want you to know I love reading your blog, and you have inspired me to tackle some of these taking apart and seeing if I can fix it myself jobs. So the other weekend our ice maker was not working at all so I youtubed it and then went about taking it apart and seeing what was going on. I am happy to report that our ice maker is now producing a lot of ice. 🙂
    Thanks for the inspiration and knowing I can do this stuff too.

    • Alana,

      That means a lot. I started this whole thing with a single purpose… tell people my stories with the hope that it might help them, help themselves. I am certainly no smarter than the average reader, just a little crazier with a screwdriver. If you’re interested, I am soliciting guest writers for the blog, so write me a story at least 500 words and you can be part of the fun. Email it to the address on the contact page. Enjoy your ice.

      Steve

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