Check-out my lifted Jeep! Sorry about that. Let’s turn to the matter at hand: a lot of us work on our own cars. When we hear on the news that a car has fallen on someone, it’s easy to dismiss it as “unlikely to ever happen to me,” and then to simply move-on. When we fail to investigate what has actually happened, we miss-out on all of the valuable information we could use to significantly minimize the chance of another tragedy.
I have reviewed some of the literature, and provide my own suggestions below for the casual reader. My suggestions are informed by my own experience and the research performed by others. Those who are interested in the research should read-on for a brief discussion of a couple studies considered.
Buy four jack stands
They’re $30/pair. Just go do it. This post will be here when you get back.
Don’t assume anything about the proper way to support your car
My own car, a Miata, has a rather touchy and dainty pair of jack rails. They are easily bent, and are only suitable for changing a tire. A quick search of the Miata.net archives returned a guide to the various other jack points of which I had not been aware. Just inboard of the jack rails, the front sub-frame, and the rear differential itself are excellent jack-points to use for a 1990-97 MX-5. Do some research for your own car, because something that should be so obvious sometimes is not.
Assess your environment – particularly the surface
It may seem obvious not to work on a slope, but the slope itself may not be evident. Does anything roll down from one end of the surface to the other? Also, never work on anything other than pavement – earth tends to get soggy.
Never work alone
Let’s discuss the unthinkable. You won’t die simply because the car has “squashed” you – you’ll suffocate long before you die of any internal injuries. Your life is not necessarily going to be over if that car falls on top of you. Even if someone isn’t there to help you in your work, you need to get someone to sit nearby and casually pay attention as you work. MAKE SURE THEY KNOW WHAT TO DO IF SOMETHING HAPPENS, because you won’t be able to instruct them if you can’t breathe.
Think twice (or thrice) before using a ramp
Ramps are easy. You drive up onto them, jack-up the rear of the car, and place it on two jack stands. Using ramps is quicker than using four jack-stands. However, there is one major disadvantage to using ramps: they’re ramp-shaped. What makes for an easy drive onto the ramps sometimes means an easy slip back off of them. All that really stands between you and a rolling car is a little bump near the top of the sloped portion of the ramp.
Control your environment
Do any kids have access to your work area? What about dogs? How likely is it that someone would carelessly interrupt you? What’s the weather like today? Who else is using your workspace?
Never, ever get under a car supported partially or entirely by a jack or jacks
Jacks are used to get the car up; jack-stands are used to support it. Period.
Never use anything that wasn’t designed to support a vehicle
You should never describe your car support set-up with any of the following words: Board, block, cinderblock, brick, rock, stone, coil spring (yes, someone has tried that before – it didn’t end well), and/or “cantilevered.”
Consider how what you’re doing affects your set-up
Are you removing a major component of the driveline? How will that affect the operation of the driveline? How will the operation of the driveline affect your set-up? Will the weight distribution be significantly affected? To where will the weight of the car shift? Are you going to be pulling on something that will pull the entire car or any portion thereof?
Driscoll, T., & Healey, S. (1999). Fatalities whilst using jacks in Australia, 1989 to 1992. Retrieved from http://www.safeworkaustralia.gov.au/sites/SWA/abou...
An Australian study published in the late 90s was particularly helpful. From 1989 to 1992, researchers studied 27 fatalities resulting from a car having fallen on someone who was performing vehicle maintenance or repair. Relying on high-quality information sources such as police and coroners’ reports, the authors summarize the relevant characteristics of each situation and the contributing factors. In not one adequately-documented fatality was it the case that a perfectly reasonable endeavor or set-up led to the car somehow falling on the deceased. In all but one of the cases (for which there was limited information available), at least one of the following contributing factors was present: a car rolling off a ramp, the use of an improper support, and/or the use of an improper work surface.
Poindexter, K., & Hardie, K. (1998). Injuries associated with hazards involving motor vehicle “jack failures”. Retrieved from http://www-nrd.nhtsa.dot.gov/Pubs/98.040.PD...
It seems as though inquiries into vehicle maintenance-related deaths and injuries were en vogue during the Nineties. A 1998 DOT publication is less helpful, but represents the only other relevant research published. The researchers relied on self-description (substantially less reliable than police or coroners’ reports), and, from this smaller sample, project the incidence of injuries in the general population. Statistics are meaningless to the individual. Statistics tend to desensitize us to the real risks rather than inspire us to take proactive measures to minimize them.
Also, bonus points to the best image annotations above
Image credit: Franklin D. Roosevelt Library (released under 17 U.S.C. § 105)