- The hydraulic jack on wheels
- A hydraulic jack with a rigid frame
- Manual machine
- Implementing the lever
- Use only on stable ground
- Put the jack in place
- Choose the right hydraulic jack model
- Maintenance of a jack
- Work safely
- The bottle jack
- Use a hydraulic jack bottle for heavy loads
- A simple bottle jack to use
- Adjust the height of its bottle jack
- Adapted saddles
- Machine tool special jack
- Jacks at all prices
The hydraulic jack allows heavy loads to be lifted effortlessly. It uses pressurized oil to push a jack on which the load rests. Especially used in mechanics and vehicle maintenance, it can also be used to disassemble a gate, lift building materials... There are two categories of jacks: rollers and bottles.
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The hydraulic jack on wheels
2. Pumping lever
3. Directional wheel
6. Articulated lifting arm
7. Hydraulic pump
9. Actuator return spring
A hydraulic jack with a rigid frame
- Consisting of a steel frame, four wheels including two directional, a hydraulic cylinder and an articulated lifting arm with a saddle, this jack can lift from 1.5 to 5 tons, with a height of lifting from 40 to 75 cm.
- To lift the articulated arm, it is necessary to carry out a pumping movement on the lever. The latter operates a hydraulic pump, with one or two pistons, which sends oil under pressure to the cylinder. The cylinder body serves as an oil reservoir.
Implementing the lever
- To limit the forces, the jack is equipped with a handle held by a screw of pressure on the pumping lever.
- Before lifting a load, prime the pump by turning the handle clockwise and then pump.
- To lower the load, simply turn the handle in the other direction.
Use only on stable ground
- To make it easier to drive and work with the most stability, the jack must be used on a flat and hard surface (concrete floor, bitumen...). Gravel or soil should be avoided. The vehicle must be stopped (handbrake or gear engaged) before being lifted.
Put the jack in place
- The saddle is the main point of support. To lift a vehicle, place the jack on the markers, usually indicated by a small triangle or hole, and usually placed near the front and rear wheels.
Choose the right hydraulic jack model
Before choosing a jack on wheels, you have to know the weight of the vehicle to raise but also the height between the ground and the rocker (ground clearance). This information is important to slip the jack easily under the vehicle. Generally 10 to 14 cm high, some models have the front thinned (7 cm) to go under a sports car with reduced ground clearance. The maximum lifting height is also important for lifting vans or SUVs, for example. These indications (maximum height and weight to be lifted) can be found either on the packaging or directly on the jack.
Maintenance of a jack
- The joints and rod of the cylinder must be greased regularly. For wheeled jacks, check also the state of the spring of return which facilitates the descent of the lifting arm.
- At ground level, the jack picks up all the dust and residues. Clean the mechanism with the blow gun or dry cloth. Do not use water because of the grease everywhere.
- A rubber sole, placed on the saddle, helps the good grip of the jack under the vehicle. It is a wear part that can be changed without problem. Over time, it hardens and loses its effectiveness.
- If the bottle jack is easy to store and transport, the wheeled model is more bulky. To lift them, the manufacturers have provided handles.
- Before lifting the jack, think about removing the handle.
- To work safely, check the tightness and condition of the moving parts regularly. A damaged wheel axle may unbalance the jack and render its use dangerous.
- If you have to work a long time under a vehicle, it is mandatory to secure the elevation with candles. This avoids a risk of falling if the jack is incorrectly positioned or if it fails.
- A car crash can cause mechanical damage and serious injury, while a candle costs only 10 to 25 €.
The bottle jack
2. Stem cylinder
3. Cylinder body
4. Hydraulic pump
5. Discharge screw
6. Telescopic lever
Use a hydraulic jack bottle for heavy loads
- Easier to design than a wheeled model, the jack bottle can lift heavier loads (from 2 to 20 tons), thanks to its lack of frame that weakens the structure. However, the stroke of the piston is limited and the lifting height does not exceed 50 cm.
A simple bottle jack to use
- The implementation is similar to that of a wheeled jack. The pump is placed on the side of the cylinder and is also activated by means of a telescopic handle.
- To prime the pump, tighten the set screw at the base of the cylinder. By loosening it, the cylinder rod drops back under the weight of the load.
Adjust the height of its bottle jack
- As the stroke of the cylinder is limited, the jacks are equipped with a threaded rod extension which allows to almost double the length.
- To better adapt to different lifting points of vehicles, the saddles have different shapes depending on the model: rectangular and wide with raised edges to fit the decks of trucks and tractors, round and smaller for light vehicles.
Machine tool special jack
- This jack bottle is a bit special. Its lifting system makes it possible to lift machine tools or large sideboard furniture. Its ground clearance is reduced (15 to 40 mm) and the load can be raised by 15 cm, which is more than enough to slip a transport cart.
Jacks at all prices
The screw jack sold with the vehicle lacks stability and only serves to change a wheel. The hydraulic jack, it allows the repetitive lifts for maintenance work: emptying, changing brake pads, gimbals or shock absorbers... Depending on the model, prices vary from 15 to more than 600 €. Wheeled models are generally more expensive, but more versatile than bottle models. For occasional use, the jacks between 25 and 100 €, sold in car center are sufficient. For a more intensive use, it is better to turn to models of big brands and prefer those with two pistons, more solid.