How Does A Hydraulic Car Lift Work?

From fixing cars to parking them for car exhibition, in every step, hydraulic car lifts are a must to have. Auto repair shops and car parking lots cannot imagine their marketing without having a hydraulic car lift at their premises.

But how does a hydraulic car lift work? A hydraulic car lift uses the working principle of Pascal’s Law. A pump continues to send high-pressure fluids from its reservoir to a hydraulic cylinder. As pressure builds up into the cylinder it forces its piston rods to extend and raise the lift off the ground. 

The pump has control valves. When they open up the oil flows back to the tank and releases the pressure. As a result, those pistons descend due to gravitational force. 

The distance between the reservoir and the piston rods also play a significant part. The greater the distance the higher the weight the system is able to raise.

how does a hydraulic car lift work

What Is A Hydraulic Car lift?

A hydraulic car lift is a device that utilizes the ‘pascal’s principle’ of fluid mechanics to lift vehicles. According to the law, if we apply some force at one end, the pressure will be transmitted to another provided they are connected with incompressible oil. 

The oil has to be pumped through a hydraulic cylinder or lines. When the fluid starts to travel from the smaller piston to larger one the force gets multiplied. 

Automobile companies and services use hydraulic car lift widely due to their controlled heavy lifting capacity. Usually, a hydraulic lift comprises a ram (piston with a cylinder), oil reservoir or tank, and pump. The ram can be positioned on either or both sides of the vertical arms. 

Pascal’s Law And Hydraulic Force  

To better understand a hydraulic car lift we need to talk a bit about Pascal’s Principle here. 

The principle states that when encircled (incompressible) fluids are pressurized the force is distributed throughout the volume equally moving in all directions. 

To easily understand this, think of two pistons (Piston A & B) in an enclosed system connected by an oil-filled pipe. Let’s say Piston B has surface area ten times greater than Piston A. 

According to the law, if we exert some force on piston A, we can see Piston B releases 10 times greater force through the fluid than what we’ve applied on Piston A. 

So, by putting ‘x’s force on a smaller inlet chamber, we get 10x strength working on the releasing end. It is an amazing way to multiply input forces making it easier to move heavy things up. 

Types of Hydraulic Car Lift

Depending on position, size, and operation, hydraulic car lifts can be of two kinds.

Holed Hydraulic Lift

Standard hydraulic lifts usually have holes. Here hole means the floor required for the lift. The hole holds a cylinder and its piston. The cylinder pushes the car lift off the ground with the help of the piston.

Holeless Hydraulic Lift

In the holeless hydraulic lift, the cylinder does not need any pit. The piston works directly on the system that operates like a jack. The system does not allow it to move more than 20 to 30 meters.

Pros and Cons of a Hydraulic Car Lift

Just like everything else, hydraulic car lifts have some benefits and drawbacks.

Pros

  • They are relatively cheaper to install
  • They occupy smaller space on a repair shop or garage
  • Hydraulics provide great lifting strength; good for lifting heavy loads
  • The elevator distributes its load evenly to the load-bearing walls
  • Overhead machine rooms are unnecessary on these type of lifts
  • Remote machine rooms are usable with this setup

Cons

  • Oil containing in the piston system tends to overheat
  • The overheating oil can produce unpleasant odors
  • During the lifting process, hydraulic lifts tend to produce noise
  • There are multiple instances of oil leakage from the pumping system
  • They are bit slower to lift, can’t move faster than 150 ft per minute

Are Hydraulic Car Lifts Safe?

There has always been a misconception about the safety of hydraulic car lifts around people. In reality, hydraulic car lifts are some of the safest options available. 

A cable-style system holds traditional style lifts. They are good when it comes to lifting performance, but they use a compressed air system. The whole contraption depends on how robust or reliable the cable is.

Hydraulic lifts don’t face this issue as they are never suspended in the air. Moreover, these lifts are held up by hydraulic arms rather than a brake system. 

The arm safely carries the lift up and down. In cases of system failure, the lift can naturally get down smoothly because of the fluid.

Moreover, every hydraulic lift goes through various safety certifications before coming to the consumer market. So, if you plan to buy a lift for your car, get one from a reputed company and check the safety certification.

What Kind Of Hydraulic Fluid Is Good For Car Lift?

For hydraulic lifts, technicians recommend only hydraulic (petroleum based with additives) fluid. Manufacturers strictly forbid using synthetic oil, automatic transmission oil, and other substitutes. 

AW (Anti-wear) 32 and AW 46 works best for hydraulic car lifts. Here the number refers to viscosity. AW 32 works better in colder conditions, and AW 46 works better in a warm climate.


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Frederick James is an expert mechanic with years of experience under his belt. He excels in diagnosing, troubleshooting, repairing, and modifying everything related to automobiles including but not limited to cars and pickup trucks. Read more...

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