- What is a jack
- Lifting capacity of jacks
- What does the pickup height affect?
- Maximum lifting height
- Types of jacks and their purpose
- How to choose a car jack
A jack is a must-have item in the trunk of every car. Even 40 years ago, every car was equipped with jacks; these were rack-and-pinion devices with a carrying capacity of 500 kg. Today we have the opportunity to choose any jacks with the necessary characteristics, which can be used both for your car and at a service station.
What is a jack
The jack is a lifting device that fixes the vehicle at a given height. Thanks to the use of the lift, it is possible to carry out tire fitting, diagnostics and repair of the suspension without a pit and a lift. Among other things, the jack can be used in everyday life where you need to lift heavy objects. The automotive market is filled with all kinds of jacks, which differ from each other in form of execution, characteristics and functionality.
Lifting capacity of jacks
It is imperative to select a jack with the correct lifting capacity. If this parameter does not fit the weight of the car, it is better not to use the jack. If the curb weight of your vehicle is 1500 kg, then the lifting capacity of the lifting device should be from 1700 kg, preferably 2 tons. If a lifting device with a lower potential is used, this can lead to immediate failure, and the suspended car will fall. What you need to know:
- for owners of passenger cars, whose maximum weight does not exceed 1,5 tons, and the ground clearance is not more than 200 mm, then choose a simple rhombic jack for 2 tons, which will be enough for tire fitting and short-term work;
- car services, and those who need long-term holding of the car in suspension, it is better to pay attention to a jack with a carrying capacity of 3 to 5 tons, which is enough for the use of SUVs and small commercial vehicles;
- for trucks, there are their own lifting devices that hold 15-30 tons. You need to choose a jack for a truck based on its maximum weight, that is, if the vehicle weighs 7 tons, its carrying capacity is 8 tons, then the jack is needed for 15 tons.
Jacks with a higher carrying capacity are more expensive in price, but they guarantee reliable support for the car, and this is your safety!
What does the pickup height affect?
The pickup height is the minimum value at which the jack starts to work. It is necessary to pay attention to this parameter, because a car with a ground clearance of 170 mm cannot be lifted by a jack with a pickup height of 15 cm.Choosing a suitable jack for this value is simple: measure the distance to the car's threshold on a flat road, if it is 150 mm, then the pickup height lift should be 70-100 mm.
Maximum lifting height
Another parameter that you should pay attention to. The meaning speaks for itself: the lift height is the maximum amount by which the vehicle can be lifted. For wheel replacement, dismantling and assembly works on suspension and gearbox removal from front-wheel drive vehicles. Adequate lifting height varies from 30 to 50 centimeters. A lift of more than 50 cm is necessary if the car wheel has fallen into a deep hole and you need to raise this side. In other cases, bricks or boards are placed under the jack.
Types of jacks and their purpose
There are corresponding jacks for each type of vehicle. They are also divided according to the installation method and the type of drive. Jacks are distinguished by the type of drive: mechanical, hydraulic and pneumatic, the latter two are actively used in car services. By type, jacks are:
- rack and pinion;
Features of screw jacks
This is the oldest type of jack, which was equipped with all Soviet cars, and is still equipped with a domestic SUV. Lada 4 × 4. The lifting capacity of the device varies from 500 kg to 1.5 tons. For such a jack, platforms with square pipes are provided. The principle of operation is simple: the jack lever is installed in a special eye in the body, moving the handle, the force on the screw of the mechanism is transmitted by the gear. Turning the handle clockwise, the car rises, in the opposite direction - lowers. The screw jack has more disadvantages than features: a small support area, because of which the jack can come off, large dimensions. If the spring is damaged by corrosion, then such a jack can no longer be used.
Advantages: low lifting effort, high lifting height and reasonable cost.
Features of rhombic jacks
Most often they are found on the shelves of automotive goods, and they are also equipped with cars. The rhombic jack can be mechanical or hydraulic. The lifting capacity varies from 0.7 to 2.2 tons. The name of the lifting device comes from its design, which consists of 4 levers, which allows using such a “lift” in cars with low ground clearance, and lifting it high.
A mechanical jack works by rotating a lever that hooks onto the jack screw. More expensive and more convenient to use are hydraulic: a hydraulic piston is used as a lifting device, which works on the principle of pumping a liquid. Such a jack is equipped with a handle, with which you pump up pressure, lifting the car. To lower the car, you need to turn the valve with the handle to release the pressure in the piston.
- affordable price;
- a wide range of manufacturers and designs;
- large support area.
- small working stroke;
- requires muscular effort to lift;
- low efficiency of the device, it takes a long time to rise (for the mechanical type).
Features of rack and pinion jacks
A wide and material-intensive mechanism is used, with a carrying capacity of up to 3500 kg. A toothed rack is used as a supporting element, along which the ratchet moves. The design allows you to lift objects not only in the vertical but also in the horizontal plane. Depending on the load, the jack can be single-stage, two-stage and three-stage. This jack is used on SUVs and ATVs.
- lifting height over 100 cm;
- low pick-up, which allows the vehicle to be lifted practically from the ground.
- large dimensions and weight;
- can damage the body if misused.
Features of lever-screw jacks
This type of jack has a lifting capacity of up to 1000 kg. The design consists of several levers and a power screw, which is driven from the handle. There are two types of lifting mechanisms:
- classic lever-screw. It uses two levers, when the screw rotates, the angle between the levers changes, due to this, the car rises or falls. The disadvantage is more effort at the beginning of the lift and insufficiently strong structure;
- combined. It is a bundle of lever and diamond-shaped jacks. The principle of operation is similar to the lever-screw, has the same disadvantages, but the jack is light and small, for small cars operating in the city this is the most acceptable option.
Features of rolling jacks
A rolling jack, according to the employees of the automotive service sector, is the most convenient and functional. Initial loading capacity 2000 kg. The design represents an improved version of the classic hydraulic jack, only with wheels and a large lever. Such a jack can be used for both cars and trucks, weighing up to 5 tons. The wide support area allows the vehicle to be lifted against the axle or subframe.
- high carrying capacity;
- wide area of contact with the jack;
- ease of movement on a flat surface;
- minimal muscular effort is required to lift.
- high weight;
- bulkiness of wheels;
- application is possible only on a flat surface.
These jacks include rolling and bottle jacks. The second type has small dimensions, carrying capacity from 0,5 to 30 tons! The principle of operation is simple: it works on the simplest Pascal's law, where two vessels filled with hydraulic oil communicate with each other. When you press the lever, oil is pumped from one chamber to another, creating excess pressure - the engine piston upward, lifting the vehicle. Return the piston to its original position allows the bleed valve, which must be turned counterclockwise. The liquid is pumped back into the first chamber by depressurization.
- high carrying capacity with small dimensions;
- requires minimal effort on the lever;
- high efficiency;
- reliability subject to compliance with the carrying capacity.
- small area of the stop;
- if oil leaks, there is a risk of a sudden drop in pressure;
- requires periodic oil changes, which tend to get dirty.
The peculiarity of the pneumatic jack is that the lifting force is carried out by compressed air. The design implies the presence of an air chamber, which expands when filled, raising the car. The pneumatic jack can be rolling or portable. For its operation, compressed air is needed, which is pumped by a compressor, so this option is not the best for domestic purposes.
- high efficiency;
- the fastest possible lifting of the car;
- ease of use;
- reliability with serviceability of valves and taps.
- a sharp fall of the car due to bleeding of a faulty valve;
- the rubber cushion may crack and suddenly leak.
How to choose a car jack
To select the required jack, we will use the following data:
- curb weight of your vehicle. Add 300 kg to this mass, so you will ensure reliability of work and your safety;
- the lifting height can be no more than 50 cm, this is quite enough for repair work on a flat surface;
- pickup height should be 30-50% less than the ground clearance of your car;
- according to the type of work, you can choose between mechanical and hydraulic, pneumatic is more suitable for service stations. For ease of use, it is better to use a hydraulic jack, if you want to save money, then a manual diamond-shaped jack will be the best choice;
- what support area you need. For service stations, this parameter should be higher; for private use, a small enough area is sufficient to match the jack. Bottle jacks are not recommended for use on cars with a bottom damaged from corrosion, otherwise the stem may pierce the metal;
- if you plan to frequently repair a car, keep it in weight for a long time, then roll-up jacks with a carrying capacity that is 0.5-1 ton higher than your car will help you.