trustywrench.com

Vehicle Air Bags

Recently National Public Radio ran a story about air bag fraud.

 http://www.npr.org/templates/story/story.php?storyId=95844517

Air bag fraud is when you buy a vehicle believing that the air bag system is functional, but an unscrupulous person has covered up air bag problems in order to sell the vehicle without the expense of a proper repair.

Here are a few things I know about air bag systems used in cars and trucks.

• They are also known as Passive Restraints because they do not require the vehicle operator to take any action for them to work. Another passive restraint is the automatic shoulder belt which was used as a transition from seat belt only systems to air bags. Non-passive or active restraints are things like seat or shoulder belts that you have to buckle yourself.
• Air bag systems are primarily electronic devices that employ an electronic module to work. This module not only determines when to deploy the air bags in a crash, but constantly monitors the system for faults.
• If a fault is detected, the system is shut down and a warning light is turned on to tell the driver that there is a problem.
• Any time the warning light stays on or flashes after prove-out, the air bags will not work.
• The warning light will be turned on, briefly, (called prove-out), each time the ignition key is turned from off to on.

To prevent yourself from being caught in a air bag fraud scheme, or just in the honest mistake of an individual seller who is unaware of the vehicle problems, do these things:

1. When looking at a car you want to buy, make sure the air bag warning light proves out
2. After prove-out, watch to see if the warning light comes back on, either steady or flashing.
3. Read the car owner’s manual to understand the particular system.
4. Inspect all the air bag components you can find. These include the driver’s air bag located in the steering wheel, the passenger air bag located in the dashboard in front of the passenger, and, if equipped, the side air bags which may be located in the seat back of the front seat or in the body around the doors. Look for covers that are not attached well, are not the right color or appear tampered with in any way.
5. If the warning light does not behave properly, take the car to a dealer to be inspected, BEFORE YOU CLOSE THE DEAL!

If you have any other questions, please ask a question in the comment link at the bottom of this page.

Good luck, Walt

Lately, I have been using a come-a-long to assist with holding control arms down on front wheel drive vehicles when I am replacing front-end parts.  In the accompanying photo, the rear control arms on a Ford Explorer are pulled down while springs are replaced on struts. On vehicles with rear leaf springs, this tool can pull the axle into place when replacing springs or the axle itself. With this helper, one has both hands free to work plus you don’t have to ask anyone else in the shop to drop what they are doing and help you. Now you can see that the come-a-long has a use besides pulling a fence tight before nailing to the post.

© 2008 Walt Christensen

Car Repair

Tips and Tricks

A primary goal of this website is to provide information to amateurs, i.e. those folks who want or need to repair their own vehicle, but who do not fix cars for a living. Today’s subject is a very useful tool that can give a helping hand to the lone mechanic.

This tool is the tie down strap,

a nylon strap with hooks on each end and a cam-lock buckle for adjustment. I frequently use this to hold a belt tensioner, engine part or strut out of the way. A pair of these straps is now my preferred way to lower a fuel tank.

            The most popular tool for releasing accessory belt tension is the serpentine belt tool. This long-handled wrench comes with extra sockets and square drives for various types of spring-loaded belt tensioners. 

 The problem you run into is that it is hard to hold the wrench with one hand and maneuver the belt with the other. I have modified my wrench by grinding a notch at the top of the handle where I can hook the strap. Drilling a hole would also work. Either will probably void the tool warranty. With this modification I can use the tie-down to hold the tensioner back while I work with the serpentine belt.

            Another place this strap comes in handy is for holding components away from the work area. For instance, when removing an intake manifold the strap can hold an A/C compressor or power steering pump off to the side. The trick is to secure the hood with a hood holding tool or broom handle, and then run the strap from a brace hole or latch loop.

            Where I have not seen others use such a strap is in gas tank repair. I now prefer this method over using a transmission jack because of the added control and stability. A transmission jack supports only the middle of the tank and so, as gas sloshes back and forth the center of gravity moves and the tank wants to tip. For long tanks, like on vans, one jack is just too risky. Two jacks would be better, but then you have to step over eight jack feet as you work. Here is my solution: I run two tie down straps under the tank. I hook them to the frame, an exhaust bracket or any convenient hole.  I then can lower each strap a bit at a time until the tank is low enough to access the harness and lines of the fuel pump. If I want the tank all the way out, I lower it onto my rolling cart. This makes the tank easy to work on. For the at-home mechanic this method allows safe tank repairs when the vehicle is on jack stands and you are on a creeper. And best of all, the strap tool is very low cost!

One more reminder: gasoline is explosive! As one who has been covered in burning gas, I say, BE CAREFUL! Not to mention that gasoline still contains benzene, a known and very dangerous carcinogen.

© Walt Christensen 2008