There are many reasons you might need to raise your vehicle, whatever yours might be, you need to know that you have the correct jack for the job.
There are several types of car jacks, from the basic scissor-type that is found in most vehicles, to heavy-duty models designed to lift large vehicles.
What is a Car Jack
A jack is a mechanical or hydraulic lifting device used to lift vehicles, partially or entirely, from the ground in order for maintenance or repair to be performed.
They require minimal energy to raise a car and achieve a safe and secure platform to complete essential mechanic work.
Reasons for Using a Car Jack
Car jacks have many more uses than for changing a flat tire. With that said, tires should be maintained throughout the year and a good jack is a vital piece of equipment if they require seasonal change.
They are essential for carrying out regular maintenance and repairs, inspecting brakes, and the undercarriage of a vehicle. A jacked-up vehicle makes many jobs easier to complete, including damage repair.
Used in conjunction with a set of stands, a vehicle can be safely raised and supported to allow repair work to be safely undertaken underneath the car.
Types of Car Jacks
There are two main types of car jacks:
- Mechanical jacks
- Hydraulic jacks
Each is designed to lift a vehicle safely, however they do so very differently.
Mechanical Car Jack
A mechanical jack is the most common. They require an operator to manually crank a lever which turns a threaded screw to ratchet a system upwards or downwards.
Types of Mechanical jacks
A scissor jack is a lightweight and portable jack, found in most cars. As their name implies, they consist of a scissor-style, crossover mechanism sandwiched between a solid base and a flat saddle support.
A long, threaded screw runs through the center of the hinge, and it is this simple system that creates powerful lift. The turn of the screw opens the scissor hinge, causing the saddle to rise and lift the load. Turning the screw counter-clockwise closes the scissor mechanism and lowers the saddle and its load.
The scissor jack is the most compact, portable, and reliable method of changing a tire, and should, therefore, be carried in all regular vehicles. In most cases, a scissor jack is provided alongside a spare tire. The provided scissor jack is designed to fit the various lifting spots on the vehicle.
If you ever find yourself needing to replace your scissor jack, ensure it lines up with the lifting spots on your vehicle and its weight.
Scissor jacks are low maintenance as they do not rely on fluid for operation, meaning they don't suffer from leaks.
A high-lift jack is a mechanical jack usually owned by farmers, off-road enthusiasts, or anyone who owns a larger-than-average vehicle.
They are constructed from strong, durable metals enabling them to lift heavy vehicles with relative ease. In general, high-lift jacks are rated up to 7,000 lbs while being able to lift up to 5 feet. However, high-lift jacks also weigh up to 30 lbs and are typically 3-5 feet in length meaning they're often not suitable for most vehicles.
They evenly distribute a load, even when the ground is soft or treacherous.
Lifting several thousands of pounds is easy and the operator exerts little physical effort.
High lift jacks can be used vertically or horizontally and are extremely versatile beyond regular vehicle maintenance and repair. They are useful tools for winching, spreading metal in the event of someone being trapped in a car accident, pulling and clamping heavy loads.
Hydraulic Car Jacks
Hydraulic car jacks work on the principle that pressure applied to a fluid in a closed system distributes equally throughout all of the systems.
In this instance, the force applied to an enclosed hydraulic system multiplies as it's compressed which supplies greater lifting power than methods that require direct physical force, such as a mechanical jack.
How Hydraulic Jacks Work
- Pressure is created as a pump plunger moves hydraulic oil through 2 cylinders
- A suction valve sucks the pump plunger back, and as it does so it draws oil into the pump chamber
- As the system repeats, pushing the plunger down again, the oil is forced through to the external discharge valve and into the cylinder chamber
- Pressure increases in the chamber as the suction valve seals off
- It is this build-up of pressure that causes the piston to rise, thus lifting the heavy object.
Types of Hydraulic Jacks
The bottle jack is vertically mounted, hence its name. They force weight in an upward direction.
They are small and narrow which suits restricted spaces, this does however limit the weight and width of their lifting load. With that said, they also require a hard, stable surface. Meaning conditions like on the side of a road for a tire change are less than ideal.
They are inexpensive, easy to use, and powerful. They require little storage and are capable of a high lift. All home mechanics and car hobbyists should own a reliable hydraulic bottle jack as they are capable of comfortably lifting 10-tonnes.
Floor jacks are long, horizontal jacks that have a low center of gravity. They lift weight directly parallel to the power source.
As they sit close to the ground they are compatible with vehicles that have a low clearance. However, they can be quite bulky and aren't ideally suited to compact spaces.
Professional workshops are the most recognized places for floor jacks, they are capable of lifting most small and medium-sized family cars.
As they are operated from a standing position, they are suitable for people with back issues and bending difficulties.
Anyone who has plenty of garage spaces and vehicles with a low profile will benefit from owning a floor jack.
Hydraulic jacks are capable of incredible lifting feats. Used in heavy construction and industry, some hydraulic jacks can lift over 200-tonnes.
Smaller jacks are commonplace in auto repair shops and garages where weight, size, and type of vehicle vary, and the jack has to withstand them all.
Tips for Jacking Up a Car Safely
Anyone who has never had to use a jack before might be understandably nervous, after all, a car can easily crush a human.
However, by following a few simple guidelines, adhering to the advice in your user's manual, and using the correct jack for the job, jacking up a vehicle can be effortless and safe.
- A car jack should only be used to raise the vehicle from the ground, never to hold it in place
- Ensure the car is in Park, or first gear if you have a manual transmission
- If you have to work on the underside of the vehicle, you MUST use jack stands capable of supporting the car's weight
- Always use a jack on a flat surface, never a slope. If there is absolutely no other option, turn the wheels in towards the curb and put chocks behind the wheels that are remaining on the ground. This will help to prevent any accidental rolling. Turn your hazard lights on if applicable
- Never attempt to change a tire on the freeway or at the side of a busy highway. Call roadside assistance or flag down a passing patrol for assistance
How to Jack Up a Car
If you have adhered to the safety guidelines, you are ready to lift your car. Here's how:
1. Chock the Opposite Wheels to the Side That You're Raising
Chocks are a wedge-shaped piece of solid rubber, metal, or wood that prevents wheels from rolling.
2. Locate the Jack Points
There are several points on the underside of the car designated for a jack, usually behind the front wheels and in front of the rear wheels.
There should also be points behind the front and rear bumpers. Failing to use these points might result in damage to the car's undercarriage and an insecure lift.
3. Place the Jack Beneath the Point
It doesn't need to be 100% accurate, there is time to maneuver it into position as it approaches the car.
4. Lift the Car
How this is achieved depends on your jack:
The mechanical scissor jack requires the user to secure the long arm/rod into place. The pumping action forces the upper and lower platforms apart, thus raising the vehicle.
A hydraulic jack, either floor or bottle time, requires the user to fasten the arm in place. Use long and slow strokes, to the top and bottom of the rod's capability, to pump the hydraulic fluid from the cylinder and raise the vehicle.
For tire changing, the car needs to be raised a couple of inches from the floor. You will feel the tension increase as the wheels leave the ground.
Keep all body parts from beneath the car, just in case the jack fails and the car drops. This could result in serious injury.
5. Insert Jack Stands
If you're going to use them, and it is highly recommended, now is the time to place the jack stands. Sit them close to the jack and gradually lower the car until it sits safely on them. Lock the stands off, lower the jack fully, and remove it.
If you're not going to be beneath the vehicle, proceed without the jack stands.
6. When the Work is Complete
Raise the vehicle slightly to remove the stands if they were used, before fully lowering the vehicle and sliding out the jack.
To lower a scissor jack twist the rod in the opposite direction used to raise the vehicle.
To lower a hydraulic jack locate the relief valve, usually a small screw net to the lever. Release the fluid slowly to prevent a sudden drop.
Lifting vehicles from the ground is an essential part of car maintenance and provided you have the correct type of car jack, it is virtually effortless and safe.
If you have any concerns before using your chosen model, refer to the user's handbook for critical advice, and better still, seek help from someone more experienced.