Failing to use jack stands when working on a car that is lifted off the ground can kill you.
Every year, hundreds of people, including mechanics who should know better, suffer serious, and even fatal injuries because they prefer to use plastic crates, bricks, logs, or even just scissor-type jacks to support the cars they work on.
But what is a jack stand exactly, and why are they safer to use when supporting a vehicle than say, bricks, or logs of wood are?
Jack stands explained
There are hundreds of different jack stand designs, but in general terms, it is a device made out of steel or aluminum that is designed in such a way that it can support the weight of a vehicle without slipping, breaking, or deforming to the point where a vehicle can slip off it to fall to the ground- as will happen when you use logs, bricks, and/or plastic crates and scissor-type jacks.
In most cases, a jack stand will resemble the Eifel Tower, with four legs that are connected by cross braces to form the base. To the base will be attached either a ratchet mechanism that is provided with a solid, positive locking mechanism, or an opening through which a thick-walled tube, or solid bar passes. In these designs, the bar or tube is provided with evenly spaced holes through a which a high-tensile strength pin passes to regulate, or adjust the height of the area of the supporting bar on which the vehicle rests.
Moreover, with pin-type jack stands, the locking pin can either rest on the top of the base, or it can pass through the both the top of the base and the adjustable tube or bar. With higher priced pin-type jack stands, the locking pin will almost always pass through both the top of the base and the adjustable tube or bar. However, there is no single “best” design, and both ratchet and pin type jack stands have advantages and disadvantages, which we will briefly explain next.
Advantages of ratchet mechanisms.
Ratchet mechanisms are easily adjustable, and all it takes is to pull out the supporting bar to the required height, where the mechanism will lock into place automatically. However, the real advantage lays in the fact that the height increments are relatively small, which makes it possible to place these jack stands under different parts of the car, and still remain on a relatively even keel, so to speak.
It often happens that with some types of repair jobs, a jack stand gets in the way of the work; thus, by having a “fine” adjustment, the jack stand can be moved to another position without upsetting the vehicle’s balance, while still providing adequate support.
Disadvantages of ratchet mechanisms.
There are no real disadvantages, apart from the fact that it is sometimes necessary to jack up the car for several inches to be able to release the ratchet. This is no great hardship, but it can sometimes be difficult to jack up a vehicle high enough to release the ratchet without upsetting the car’s balance, and particularly so when the car is resting on four ratchet type stands.
Advantages of pin-type jack stands.
While ratchet-type jack stands are safe enough, pin-type stands are almost indestructible, since the locking pin makes it impossible for the supporting bar to slip through the base. This type of jack stand is the preferred stand for heavy vehicles, because they are the strongest, and most reliable stand to use in this application.
Moreover, with this type of stand, it is not necessary to jack up the vehicle more than a few millimetres to release the pin; as soon as the vehicle’s weight is supported by the jack, the pin can be released and the stand removed from under the car without upsetting the car’s balance, even if it rests on four stands.
Disadvantages of pin-type jack stands.
With long use, the locking pins can bend, which can make it difficult to insert, and extract the pins, especially if the pin passes through both the base and the supporting bar, but this is easily rectified by replacing the pins.
However, the real disadvantage of this type of stand is that the height increments are usually far apart, which means that it can sometimes be difficult to support a vehicle evenly if four stands are used, but the same supporting points are not available on both sides of the car. Many repair jobs make it impossible to place jack stands at the same spot on both sides, so you might end up with a car that is not perfectly balanced with this type of stand.
What to look for in jack stands.
Many reviewers maintain that the sign of a superior jack stand is the quality of the finish, but the truth is that paint or powder coating can hide a multitude of sins. There are several critically important aspects other than the finish to consider when buying jack stands, and in the case of steel stands, you should look for the following:
Check the rating.
There are jack stands available to hold any weight from one ton, to as much as fifty tons, but for general repair work on light vehicles a rating of three tons per stand is more than sufficient. However, this rating refers to the fact that EACH stand must be able to support three tons, and NOT the fact that two stands must be able to support three tons between them. Most brands are sold in sets of two, so with one set, you will be able to support a weight of six tons. For general DIY applications this is more than anyone will ever need to support a light vehicle.
However, if you are going to use jack stands to support a light truck or SUV, you need stands that are rated at six tons each, not only because trucks and SUV’s are heavier than passenger cars, but because six-ton stands can extend to as high as 22 inches, depending on the brand. Lighter rated stands do not have the reach, so invest in six-ton stands, even if you are never going to need, or use their full carrying capacity.
Construction of the base
Good quality jack stand bases are almost always made form one piece of sheet metal, which means that there is only one joint, and therefore only one weld, apart from the welds that join the ratchet, or sliding support bar sleeve to the base. As a rule of thumb, the fewer welds there are in a jack stand, the higher its quality and reliability. Therefore, look for only one weld in the base, and two or three welds on the locking mechanism. Your safety depends on this aspect!
The base of a cheap, substandard jack stand is more often than not constructed from several pieces of metal that are welded together. Moreover, the welding is often of an abysmally poor standard, and you place your life at risk when you use such a product, so avoid any jack stand that has more than one weld in the base.
Check how well the sliding parts fit
The sliding parts should slide freely, with no binding or catching. However, the sliding parts must fit into the base neatly, and with only minimal free play. Excessive free play is the hall mark of a substandard product, and there is an excellent chance that the ratchet on such a stand could fail the first time you use it. As a rule of thumb, the more free play there is in the sliding parts, the worse the quality of the product, regardless of how attractive the paint job on it is.
Choose the widest base.
Logic (and experience) dictates that the wider the base of the jack stand is, the larger the force required to make the stand fall over, such as when the car that is being worked on is shaken during a repair procedure. This is particularly important to bear in mind when the surface of the work area is not perfectly smooth and level.
The widely spaced legs of most jack stands make it possible (and safe) to support a vehicle on surfaces that are not perfectly level, since the weight that each stands supports is spread over a large area.
Avoid jack stands with square base-plate bases.
Some designs, and particularly stands that are made from cast aluminum, have square base plates, instead of four, widely spaced legs. While stands of this design have their uses, it must be remembered that in many cases, their bases cover less than 75% of the area covered by a conventional stand with legs.
This means that it is much easier to push a vehicle off these stands because their bases do not spread the weight of the vehicle over as large an area as conventional stands do. In short, these stands are ridiculously, if not dangerously easy to topple, and many accidents and injuries are caused by jack stands that topple over, and especially during transmission and engine replacements that are often accompanied by severe shaking of the vehicle.
However, jack stands of this design are usually very light, and don’t take up much space under a vehicle, but they are not recommended for use where excessive movement of a vehicle could cause them to topple over.
Jack stand safety.
Jack stands offer a fail-safe way to support a vehicle when its wheels are off the ground, and you have only yourself to blame when a car falls on top of you because you only used a jack to support it. However, even the best quality jack stands can injure you if you use them incorrectly; therefore, we have compiled a short list of tips and tricks on how to use jack stands safely. Here is how-
- Discard any jack stand that is damaged in any way. Any attempt to repair a jack stand puts your life at risk, since you cannot restore its strength to what it was when it was new.
- Always use stands of the same design on a vehicle if you use more than one. This way you can set them to the same height much more easily than you could with disparate designs.
- Only work on level surfaces, and NEVER use, or make extensions to extend the height of a stand. If you cannot make the height you require, use a bigger stand.
- Never use a hammer to insert or extract a locking pin, or to release a ratchet mechanism on a jack stand. If you have to use hammer for this, the jack stand is either bent, broken, or damaged in some way, and it is not safe to use. Do the smart thing, and discard it.
- If you have to support a car with four stands, do NOT jack up either the front or back end to the height you require in one go. If you do, and you place jack stands under the high end, the car will be severely unbalanced when you start to lift the other end. Even the best jack stands cannot overcome the laws of physics, so do the smart thing and jack the car up in stages to prevent it sliding off the jack stands.
- Do the same thing when you lower the car to the ground; lower the height of the jack stands both in the front and the rear in stages, to keep the car as level as possible during the entire jacking or lowering process.
One more thing…
At the risk of stating the obvious, it is very important to inspect all the jack stands in your possession on a regular basis. Check for signs of splitting welds, deformation of the legs, and especially wear on the teeth of the ratchet mechanisms. No attempt should be made to repair any defect, and especially trying to re-weld joints with normal arc welding equipment. This type of welding is hard and brittle, and can weaken the material adjacent to the joint, which can lead to the failure of the joint. Look after your jack stands, and they will look after you!