Incorrect installation jack under the bottom of the car often leads to crushed sills, damage to suspension elements, or even to the car falling to the ground. Precise installation of the lifting mechanism into the standard technological hole is the only safe way to replace a wheel or repair the chassis. Mistakes at this stage can cost you expensive auto body repairs or, worse, cause serious injury.
In this guide, we will look at how to properly jack a car, taking into account the body structure and the type of equipment used. You will learn about the critical support points that the manufacturer has provided for lifting, and you will understand why you cannot rely on intuition. Compliance with these rules ensures that the car remains intact and you do not get any health problems.
Choosing a suitable location and preparing the car
The first thing you need to do before lifting your car is to find a perfectly flat and hard surface. Asphalt or concrete are the best choices, while dirt, grass or snow can cause the jack support to sink and cause structural instability. If you are forced to stop on the side of a slope, be sure to turn off the engine, turn on parking brake and place the car in gear.
For an automatic transmission, the selector is moved to position PARK, and for mechanics, first gear or reverse gear is engaged. This will prevent the machine from rolling away spontaneously during operation. Additionally, under the wheels that remain on the ground, it is necessary to place wheel chocks or at least massive stones and bricks.
Before lifting, loosen the bolts of the wheel you plan to remove. This must be done while the entire mass of the car is on the ground, since the wheel will spin in the air, and it will be almost impossible to remove the tightened nuts. Use a standard wheel wrench or a more powerful telescopic wrench to strip the threads.
⚠️ Attention: Never attempt to lift a vehicle if there is loose soil or ice under the jack. Place a wide board or metal sheet under the heel of the jack to increase the support area.
Finding standard lifting points on the body
Every modern car has specially reinforced places for installing a jack, which are usually located along the sills. On many models, these zones are indicated by special triangular cutouts in the plastic edging of the threshold or by arrow-shaped marks applied directly to the metal. Installing a lifting device in an arbitrary place will lead to deformation of the thin metal of the bottom.
On cars with a monocoque body, the lifting points are often reinforced ribs running along the side members. Owners BMW, Mercedes or Audi You should be especially careful, since the thresholds of these brands are often made of aluminum alloys or have a complex composite structure that can be damaged if contact is incorrect.
If you are using a hydraulic trolley jack, make sure that its top platform (“fungus” or foot) has a rubber gasket. This gasket prevents metal from sliding against metal and protects the paintwork from scratches. In some cases, for example, when lifting by a subframe, it is necessary to use special adapters or wooden blocks.
Where can I find information about lifting points?-->
spoiler: A detailed diagram of the location of the lifting points is always in the vehicle’s operating instructions (section “Replacing a wheel” or “Emergency”). If there is no manual, look for plastic plugs on the thresholds or characteristic metal thickenings.
Technology of installation and lifting with various types of jacks
The lifting process depends on the type of equipment used. Standard screw jacks (“diamonds”) require the screw to be rotated until it makes firm contact with the body, after which the force is transferred to the lever. Hydraulic rolling jacks lift the load more smoothly, but require more space under the vehicle to move into.
When working with rack and pinion jacks (hi-jacks), it is important to take special care, as they create a very high center of gravity and can tip the car over at the slightest misalignment. For passenger cars on asphalt, their use is not recommended without special extension platforms. Make sure the jack rod is positioned strictly vertical.
Raise the vehicle smoothly, constantly monitoring stability. After the wheel lifts 2-3 centimeters from the ground, stop lifting and check the structure for stability by gently rocking it. If you hear a cracking sound or see the metal of the threshold begin to deform, immediately lower the car and change the installation point.
Ensuring safety when under the car
It is strictly forbidden to stand under a car that is only raised on a jack. A jack is a lifting device, not a safety support. Hydraulics can leak, a screw can turn, and metal can burst at any moment. For any work under the bottom it is necessary to use safety racks (tragus).
After raising the car to the desired height, carefully place the safety stands under strong suspension or frame components, close to the jack, but not interfering with it. Lower the car onto the racks so that the weight is completely transferred to them, and the jack remains tensioned as a secondary safety net. Only after this can you crawl under the car.
If you are changing a tire on the side of the road and do not have racks, place the removed wheel flat under the threshold of the car on the opposite side of the jack. If the car falls, the wheel will take the impact and save your life by creating a life-saving gap. This is an old but effective emergency safety method.
⚠️ Attention: Never crawl under a car while it's only on a jack, even if you're just “checking” something for a second. The statistics on injuries in garages are relentless.
Comparison of types of jacks and their applications
The choice of instrument directly affects the safety and convenience of the procedure. The table below provides a comparison of the main types of jacks used by car enthusiasts.
| Jack type | Load capacity | Sustainability | Recommended Application |
|---|---|---|---|
| Screw (diamond) | Low (up to 1.5 t) | Average | Emergency wheel change on the go |
| Trolley hydraulic | High (2-3 t) | High | Garage repair, tire fitting |
| Rack and pinion (hi-jack) | Medium (up to 3 t) | Low (on asphalt) | SUVs, mud, sand |
| Inflatable pillow | Medium (up to 2 t) | High (large area) | Smooth asphalt, low ground clearance |
Regular screw jacks, supplied with the machine, are intended exclusively for emergency situations. They have a small support area and require significant physical effort. For regular maintenance in the garage, it is better to purchase a high-quality rolling jack with a lifting capacity of at least 2 tons.
Inflatable airbags are becoming increasingly popular due to their compactness and ability to lift a car even with minimal ground clearance. However, they are puncture sensitive and require a source of compressed air or exhaust gas, limiting their versatility.
Tip: Always keep a piece of thick plywood or rubber mat in the trunk. This will help install the jack on soft ground and not damage the surface of the site.
Common mistakes and precautions
One of the most common mistakes is installing a jack under a plastic body kit, bumper or diffuser. The plastic will instantly rub under load and the car will collapse. It is also dangerous to lift the car by the suspension arms if they are not designed for this, as you can disrupt the wheel alignment or damage the silent blocks.
Don't forget about ground clearance. On lowered cars or cars with aerodynamic body kits, a standard jack may simply not fit under the stop point. In such cases, you must first slightly raise the car with a hi-jack through the hole in the bumper (if any) or use special low lifters.
After completing the work, lower the vehicle slowly. A sudden load release can cause the jack to slip and damage the newly installed wheel or brake lines. Make sure that no one is holding on to the vehicle as it touches the ground.
⚠️ Attention: If you feel that the metal of the threshold has begun to “float” or hear a characteristic crunch, stop lifting immediately. Move the jack to a larger wood spacer or find a stronger support point (such as a subframe over a spacer).
The main conclusion: The jack is only for lifting, the stand is for holding. Never neglect insurance.
Completion of work and checking the result
After the wheel is installed and the car is lowered to the ground, it is necessary to finally tighten the mounting bolts. Tightening should be done crosswise so that the disc fits evenly without distortion. Use a torque wrench to maintain the tightening torque specified by the manufacturer, usually from 90 to 120 Nm depending on the car model.
Be sure to remove all tools and check for jacks, stands, or forgotten items under the vehicle. After 50-100 kilometers, be sure to check the tightness of the wheel bolts again, as they may become loose after the first load.
Check the condition of your jack regularly. Hydraulic oil should not leak, and the screw pair should be lubricated and free of jams. A serviceable tool is the key to ensuring that you can safely change a tire in a critical situation on the highway.
What to do if the thread on a wheel bolt is broken?-->
spoiler: If the bolt turns but does not tighten, the threads in the hub may be stripped. In this case, movement cannot be continued. The stud or hub needs to be replaced at the nearest service center. Use the spare tire only at a service station.
Is it possible to jack up a car by the bumper?
Absolutely not. The bumpers are made of plastic and are attached with latches. They will not support the weight of the car and will break, causing the car to fall and damage the body.
Do I need to completely remove the jack bolts before installation?
Yes, the screw must be fully lowered for the jack to reach its minimum folded height. This is critical for cars with low ground clearance.
How often should the oil in a hydraulic jack be changed?
It is recommended that the hydraulic oil (spindle) be serviced and replaced once a year, or when lifting properties are lost if you use the jack regularly.
What to do if the jack falls off its fulcrum?
Immediately jump to a safe area. Do not try to catch a falling car with your hands. After an incident, inspect the lifting point for damage and select a more secure location or use a spacer.
Is a car jack suitable for an SUV?
Only if the jack's lifting capacity exceeds half the weight of the SUV. However, standard “diamonds” often have a short stroke and low stability, which is dangerous for heavy and tall vehicles.