Car jacks – the floor or garage type – are indispensable tools for any auto service shop, and the same care should be taken in shopping for them as for any other lift. There is always a risk of serious injury from using the wrong jack for the task, or using the correct one improperly. Fundamental to choosing the correct one is distinguishing the various types and their applications. Screw jacks, bottle jacks, toe jacks, ratchet jacks and under-axle jacks are just some of the most common. They are not interchangeable, however, even if they share the same load capacity.
Important considerations in choosing a jack are reach, maximum load or lifting capacity, jack weight and operational features such as a low profile or multiple lift points (saddles). Depending on features, a floor car jack can cost from less than $100 to more than $2,000. A jack’s maximum lifting capacity is stated in its specifications, and typical ratings for automotive service jacks are in the range of 3 to 10 tons, but even 20- and 25-ton capacities are readily available. Most floor jacks in auto service use hydraulic power to provide lift or ease of operation. Do not exceed rated capacity. Overloading can cause the hydraulic system to fail, so choose a lifting capacity adequate for the task, with some to spare.
Often rated for 10 tons or more, air-hydraulic service jacks use a combination of shop air (usually in the range of 80-150 psi) and hydraulic force to increase lifting speeds and reduce manual effort.
It is important to remember that hydraulic service jacks are designed to lift, not support, their rated-capacity loads, which consist of one end of a vehicle. Immediately after lifting, the load must be supported by a pair of appropriately rated jack stands. The rated capacity of jack stands is per pair, not for each one. A number of manufacturers now offer kits consisting of a jack and a pair of jack stands to help reinforce this practice.
When choosing a jack, consider convenience features such as foot-pedal operation to raise the saddle to the lifting point, dual pumps for quicker lift, safety overload to prevent using the jack beyond its rated capacity, extreme low profile (some jacks offer a minimum lifting height under three inches), or a built-in tray for fasteners and tools. Look for warranties on quality jacks to cover parts and labor for one or two years.
Automotive service jacks should meet or exceed the American Society of Mechanical Engineers (ASME) safety standard for Portable Automotive Lifting Devices (PALD). The latest version of these standards, which apply to the design, testing, operation, maintenance and inspection of various vehicle jacks, mobile lifts and support stands, was approved by the American National Standards Institute (ANSI) in November 2009.
