Peculiarities of selecting hydraulic jacks for the car
Every motorist, experienced and not so experienced, is familiar with such a device as a jack. This is the jack that allows you to lift and fix the car when you need to make repairs. Whether the jack works horizontally at home or on the road makes no difference. It is impossible to make a repair without a jack.
The jack has been a standard feature in many vehicles since the factory. However, as a rule, the device that the manufacturer offers us is the simplest and the most budgetary. It is a mechanical car jack, which in addition to low lifting capacity has another huge disadvantage. the need to exert very great effort to raise the machine to the required height. And it’s not very stable either. That’s why many car owners think about buying a good jack for travels and repairs at home. Some of the best hydraulic bottle jacks and car jacks in terms of price/quality ratio are. Here, the pressure of the working fluid is used instead of normal human physical strength. Such jacks are much easier, lighter and more reliable to use. They are quite mobile and not heavy in weight. And they can cope not only with an ordinary unloaded car, but also with a more serious car: a jeep or even a truck.
How does the hydraulic elevator work?
Hydraulic elevators work on the principle of communicating vessels with technical oil. Any hydraulic hoist contains two vessels with two valves: a discharge valve and a suction valve. It is the valves that help create and hold the necessary pressure in the operating cylinder. In one of the tanks is hydraulic oil, which is pumped using a special handle into the second, and which lifts the piston, and with it the car. Valves do not allow spontaneous return of the fluid back, hold the set pressure. The car is lowered to the ground only after opening the valve with a special screw. So the jack is designed to hold the vehicle reliably and safely for the required length of time.
The principle of operation of the hydraulic elevator (jack)
Briefly about the main faults
The most common complaint encountered on forums is that the hydraulic jack does not lift.
Design and principle of operation
The design of hydraulic jacks is about the same for jacking jacks as it is for bottle jacks. The main parts of the jacking devices:
When the handle is lifted up, the shutoff valve is actuated, the oil flows into the chamber through the operation of the suction valve. The piston is raised by pumping oil from the reservoir to the inside of the master cylinder. Then, to lower the piston with the piston rod, the bypass valve is opened, then the piston will be lowered under load pressure.
Jacking points
When removing and installing a wheel on the car, it is always necessary to use a jack or other lifting mechanism, which may be equipped with a service station or tire fitting shop. Installing the spare or changing wheels for the season, the motorist often faces the need to use the jack. When replacing a wheel yourself, you usually use a screw, hydraulic or rack-and-pinion jack, which is usually included with the necessary tools that come with the car. In tire shops or service stations, hydraulic jacks or pneumatic jacks are usually used, often specialized lifting stands and hydraulic mechanisms with automated control system are also used.
When using the jack to replace the wheel yourself, it is important to clearly identify the location of the jack. Usually the places for mounting the jack are marked on the illustration in the technical documentation of the vehicle, but in the absence of such documentation, it is not difficult to determine them yourself.
For example, on most domestic cars, this is a small area on the sill right next to the wheel, usually reinforced with a metal profile or plate. On foreign-made cars (Japanese, French, American, etc.).д.In addition, on many foreign executive class cars (in Russia, it is mainly German cars), the place for mounting the jack is marked with arrows or triangles and has a special rubber cushion that protects the sill from possible damage.
If the sill of the car is rotten or deformed, as well as when it is necessary to lift two wheels at once (which is quite often used in tire shops during seasonal tire change), it is allowed to install the jack under another supporting part of the body, which can be a lever support, the end part of the shock absorber rack, gearbox (on jeeps and gazelles), beam, supporting part of the bottom, etc.д.
At installation of the jack under heavy vehicles, such as Jeep, UAZ, GAZel, and as under some crossovers and station wagons (and sometimes sedans of some brands), it is necessary to look carefully a front and a back part of the vehicle under the bottom in order to find the bearing support or a beam having the designated platform for mating with a cup of the jack. In this case two front or rear wheels will be lifted at once. Under no circumstances should the jack be installed under the threshold on heavy vehicles, as it will inevitably lead to its deformation.
How to jack the TLC Prado
There is a glove compartment in the tailgate that contains the tools needed to change the spare tire.
- Pull out the parts of the screwdriver. Assemble the 3 parts into each other and tighten them with a bolt.
- Use a screwdriver to release the catch and insert a screwdriver at an angle. Rotate counterclockwise to lower the spare wheel.
- Pull the lowered wheel towards yourself, unscrew the nuts of the lifting mechanism.
- Also don’t forget to loose the nuts on the punctured wheel.
- Dismount the air suspension.
- Pull the elevator out of the trunk wall.
- Place it in the desired position. In front under the frame or behind under the axle, depending on the wheel to be changed.
- Add a 4th link to the collar.
- Use the turnbuckle to raise the car to the required height.
- Unscrew the nuts from the wheel on the car, remove it.
- Pull up the spare tire and install it in place of the removed wheel. Tighten the nuts.
- Lower the hoist with a screwdriver.
- Tighten the nuts on the replaced wheel well.
- Withdrawn wheel to roll up to the lifting mechanism, lift and tighten the nuts. Turn the thumbwheel clockwise until the spring is fully raised and locked.
You don’t need to have special knowledge when changing the spare using a regular jack. The main thing to do everything correctly. The jack on the Prado 150 under the designated places, it will protect the body of the car.
Why the jack will not lower or raise
Reasons why the jack refuses to work:
- Cylinder failure. The working plane does not hold the load, as a result the fluid flows from the cavity to the piston space.
- Mirror damage. The hydraulics loses efficiency or simply fails, it occurs due to improper transportation, it can lead to the fact that there is an oil leak and air enters the chamber, in this case, corrosion is sure to occur over time.
- Corrosion. Leads to rapid wear of oil seals and packings, as a result dirt may get into the fluid and clog channels and valves.
- Dropping of the machine. The greater the height from which the jack falls, the more serious may be the deformation of parts, major components.
- Too much load. Causes distortion of the stem. This leads to warping of major components and loss of oil.
- Improper use, as well as untimely oil changes.
Warped piston rod
Troubleshooting
Oil leakage is the main problem that causes the jack not to lift until the end (a small leakage) or in general (a significant leakage). Because of this air enters the cavity, then the jack works at a low force or refuses to work at all. Leakage in the hydraulic system can be prevented by routine maintenance, checking the oil level. In the case of a low level, simply top up the fluid to normal.
Air leaks into the hydraulics due to lack of fluid. This problem can be solved by pumping: you must unscrew the plug of the oil reservoir and overflow valve, and then just pump the system, that is move the lever up and down until the fluid flows into the main cylinder.
Corrosion on the pistons, rods, and cavity of the jack is often the cause of failure. To find out the cause and repair it in detail, you will have to disassemble the device.
A bent piston rod is also a common reason why a jack does not lift or jerks. In such a case it is possible to change the given element either by taking an analogue from the old model or buying a new one. In most cases such malfunctions cannot be repaired at all, even in a workshop or service center. This is because the piston rod usually bends under impact loading, and in that case the main body components are damaged. In this case, it is cheaper to buy a new unit, without repairing or replacing individual parts.
When the bypass valve is deformed or just dirt accumulates in it, the ball of the valve sits tightly in its seat and the hydraulic fluid leaks through it. In this case it must be simply replaced and the old (contaminated) oil changed for the new one.
Change of oil
Types and causes of breakages
The hydraulic jack can be repaired with your own hands. To do this learn all possible malfunctions and how to rectify them. Parts are prepared in advance. for replacement of defective parts. The main causes of failure and the rules for their removal are known. For this purpose it is necessary to have the suitable tools at hands.
Hydraulic cylinder malfunction
If a hydraulic cylinder is defective, the oil reservoir must be removed. First the piston is disconnected. To do this loosen the screws on the top of the oil reservoir with a wrench. Protective rings are removed, the tank is pulled out. If cylinder is damaged, it must be replaced. In the process of installation will require the presence of a clamp. Unscrewed bolts from the jack and replace with new ones. They are of the same size. If the sleeves that have been removed are worn out, other sleeves are put in. O-ring type is permitted on some models.
Upper and lower ring protrusion
If the top ring has protruded, the top plate must be unplugged. It is inspected beforehand for any defects. Screws are to be unscrewed using wrenches. It is important to inspect the piston to ensure that the broken ring has not damaged it. After that, proceed to install a new one on the piston rod. Use a sealant to improve retention.
If the lower ring has popped out, the lower frame should be removed. At this point the hydraulic cylinder is inspected. Check its integrity. It is important that the piston moves smoothly, without sticking.
To remove the frame, the jack is turned over and secured securely. The cover is removed only after the O-ring is inspected. Using a screwdriver, remove the retractable extension arm. It also needs to be inspected, since there is a risk that the ring will damage it.
If it is replaced, check the markings on the housing or in the documentation.
The rod is lubricated with machine oil during installation. A new ring is also installed.
Breakage of the traction lever
The difficulty of this repair is that it requires removal of both the traction device and the cylinder. First remove the top cover and inspect the cylinder. There may be scratches on it. Sometimes the moving platen also needs to be replaced.
The cylinder is removed using a clamp, and the top plate is held by the rods. If the design contains several pistons, the removal of the coil is also required.
The pulling device with the connected lever is on the bottom plate. To remove the lever, the rod is loosened with a hammer. In the last step, the lever is fixed to the pulling device.
Breakage of the wedge gripper
If this is the case, the top plate must be unplugged. To do this, 4 screws are unscrewed. Use a screwdriver to pry open and remove the coupler. It is located near the oil system.
Then the pinch bar, located on the rod, is removed. The plate is inspected before a new one is installed. Reassemble in reverse order.
Remove the jack plate
When repairing such a breakdown, first of all the piston system is checked. It may have been damaged. Depending on the type of jack, there are different bolts to fix the plate. As a rule, they have a thread of M6. There are four of them and they are located at the edges. When replacing the plate, the oil system should also be checked, as it may also be damaged.
Hinge replacement
This type of repair is easy to do with your own hands. Unscrew the screws and remove the top plate. After that, the disconnection of the rod is carried out, the hinge is easily removed. It is often bent. Using a machine tool its surface is smoothed. In case of a large deformation, it is better to replace such a product with a new one.
Joint is defective
This failure is directly related to poor pipe work. Inspect the piston system. Due to its failure, the coupler is experiencing increased pressure. To do this, the piston assembly is dismantled and the fault is looked for in it. If possible, it should be repaired. Otherwise this part of the jack must be replaced.
Troubleshooting of the piping
This type of repair is performed by service centers. The jack can be inspected at home and only minor repairs can be made.
To do this, the bolts are unscrewed and the top plate is removed. Use a screwdriver to undermine and then remove the coupler. If the external examination shows a tear in the top nut, this fault cannot be repaired at home.
Repair instructions and spare parts selection
Repair of the hydraulic jack begins with its disassembly. All parts are screwed, so wrenches are needed.
- The oil must be drained out. A special container should be prepared for this purpose.
- The piston and valve are removed. Visually inspect them. All dirt and rust is cleaned.
- Deformed piston rod may be the cause. The jack cannot lift the load. In this case the part must be replaced.
- The gaskets must be inspected carefully. If no defects are found during visual inspection, it is still better to replace them. Often microscopic defects are not visible, but can be the cause of a malfunction.
- The oil valve is checked. Remove the dirt that could stick to the gaskets. The ball is in the wrong position because of its presence and oil is leaking.
All parts of the disassembled unit are washed in a special liquid. Faulty parts are replaced. Parts are available for this purpose. All new parts must have the same parameters. Repair kits are available to replace small structural parts. They include the parts and the gaskets between them. Reassembly is carried out in the reverse order.
Change and rules of oil refilling
Before pouring in new oil, the old oil is completely removed. If there is flushing fluid present it should be removed as well.
Before pouring in new oil, all air trapped inside is removed. Open the outlet valve and lower the device down. Then at least 5 pumpings should be carried out. Remove the bolt from the filler neck and pour the oil through the nozzle to the required level. Then the pumping is repeated and the oil is refilled. It is important to bleed all air from the system. As soon as the oil is no longer bubbling and has reached the proper level the jack is ready for use.
Rules of repair and selection of spare parts
Repair of the hydraulic jack begins with its disassembly. All the parts are threaded, so wrenches should be available.
- The oil must be drained out. Prepare a special container for this purpose.
- The piston and valve are removed. Visually inspect them. All dirt and rust is cleaned off.
- Deformed piston rod may be the cause of the malfunction. The jack can not lift the load. In this case the part must be replaced.
- Gaskets must be inspected carefully. If no defects are found upon external inspection, it is still better to replace them. Often microscopic imperfections are not visible, but they are the cause of the malfunction.
- Check oil valve. Remove the clogged dirt. The ball is in the wrong position because of its presence and oil is leaking.
All parts of the disassembled device are washed in special liquids. Defective parts are replaced. Parts are selected for this purpose. All new components must have the same parameters. Repair kits are available for replacement of small structural components. They include parts and gaskets between them. Reassembly is carried out in the reverse order.
Oil change and priming rules
Before pouring in the new oil, the old oil is completely removed. If there is any flushing fluid, it is also removed.
Before filling with the new one, all air present must be removed. The release valve is opened and the device is lowered down. Then at least 5 flushes should be performed. Remove the bolt from the filler neck and pour in oil up to the required level through the nozzle. Then the pumping is repeated and the oil is refilled. It is important to bleed all air from the system. As soon as the oil surface stops bubbling and reaches the proper mark the jack is ready for operation.
Rules for operating a 5 and 12-ton jack.
If the jack is operated correctly, the number of breakdowns will be drastically reduced.
To do so, the following rules must be followed:
- Do not lift more than the permitted load.
- The work is done smoothly, without jerking.
- Only allow unit to be set up on a level surface.
- Lubricate all moving parts before starting work.
- The unit is inspected externally to look for cracks or oil leaks.
- The oil level is checked and should be brought up to normal.
To keep the bottle jack operating correctly, monthly maintenance is required. As the product is constantly under great strain, all parts require lubrication. It is important to avoid dirt, which causes the machine to jam. The unit is stored in the lowered state.
Hydraulic jack schematics
Hydraulic jack disassembled
There are several objective reasons why the lifting equipment will not fully or partially function. Most often their appearance is connected with violation of operating rules. The bottle jack may be subjected to forces exceeding the specifications. In this case, it will be necessary to make repairs.
The most common malfunctions of a hydraulic jack:
- stopping. Most often, it is caused by a lack of oil or a clogged filter. To find out the cause, you need to disassemble the design and make repairs or fill the tank with working fluid;
- No piston can be raised. Explained by insufficient working fluid volume;
- Slow or jerky lifting;. Piston does not rise. The cause is the presence of air in the system, its action on the piston;
- pressure drop. Need to repair the valve or replace it completely.
often than not, after taking apart the housing, the problem is immediately visible. If the cause of the problem is mechanical damage to the housing or piston, it is best to buy a new jack, rather than repairing an old one.
The video clearly shows the principle of operation of the hydraulic bottle jack:
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Repair of mobile hydraulic jack with your own hands
Hydraulic jack repair begins with removal of the lifting piston and its inspection for corrosion and deformation. If these defects are found, it is recommended that the piston be replaced with a new one.
Then the valve is rinsed from dirt and checked, and the oil is pumped under the piston. If there are traces of deformation or any other defects, the valve is simply replaced with a new one from the repair kit.
The seat valve prevents fluid from flowing from under the piston back to the jack‘s reservoir and must be thoroughly cleaned of dirt, as well as tightly covering the valve bore.
After inspection and cleaning, all parts are washed in kerosene, and the defective parts are replaced with new ones and reinstalled in their places. And all gaskets and collars are also replaced. After the elevator is completely assembled, it is filled with fresh oil.
Purge the system of air
After a long time of using the jack, air bubbles gradually accumulate in its working fluid, slowing down the piston’s exit velocity.
To do this, open the valve that lets the working fluid from the jack’s working compartment into the reserve tank.
Then, having removed the cap from the tank, quickly pump the oil several times. After several pumps, the operator compartment should be completely vented and the unit will return to normal operation. If pumping is not successful, the oil should be pumped again.
Filling up the oil
It consists of two actions. flushing and pouring. After the old fluid is drained off, the flushing fluid is poured in instead. It can be freely purchased in a construction store.
After that you should pump the jack at least 3-4 times, then refill the liquid and pump a couple more times. Drain the flushing fluid in the same manner as the used oil.
The piston must be fully inserted into the jack body when priming. Oil is poured under the very top of the oil tank hole. Then, after closing the tank lid, pump the mechanism about 5 times, at the same time oil level in the tank will decrease, so after each pumping it must be filled.
When the fluid level after pumping stops decreasing, you should open the bypass valve and pump the jack a couple more times until the filled oil is free of air bubbles.
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Instructions for the proper pumping of the jack device
Scheme of filling the hydraulic jack with oil.
Among jacks advantages are rigid construction, as well as load lifting height from the ground, the highest lifting capacity with smooth running, minimal lifting height. All these advantages give high efficiency.
The reasons of failure of the equipment can be any. For example, prolonged use of the device may cause air accumulation in the form of bubbles. This reduces the efficiency of using the jack, i.e. its efficiency drops sharply. This is caused by air entering the hydraulic mechanism due to a lack of hydraulic fluid.
Pumping and troubleshooting the jack
The following actions will help bring the unit back to its original condition:
- The jack should be started with the by-pass valve and oil reservoir plug open.
- Pump the pump of the device a certain number of times, which will displace all the accumulated air from the working cavity into a special container for the liquid.
- To close the oil tank hole and bypass valve.
Otherwise the above actions, according to the instructions, are repeated.
How to properly pump the jack using a different algorithm
It is recommended to replace corroded parts.
Since the above method of pumping the jack is not the only method, you can perform the following steps:
- If the jack slowly lifts the load or if it is completely defective, the presence of air in the cavity of the device is determined.
- The locking needle should not be unscrewed by 1.5-2 turns, and the jack plunger is lifted by the screw to the upper point, which is the extreme point, and then it is lowered again to return to the bottom position.
The last operation is repeated 2 to 3 times. To prevent this problem, periodically check the fluid level in the jack. If it is not enough, the oil must be added.
The jack is to be pumped again after impurities have entered the working cavity. Unscrew casing head to remove contamination, then pour kerosene into the base of the casing. Then the jack is pumped by first unloading the stop needle. After completing the operation, the kerosene is removed and the working cavity is filled with clean hydraulic fluid.
In general, the algorithm is as follows:
- Pour in the oil, then close the box.
- The piston should be pumped by raising it to its limit.
- The plug is unscrewed and the piston is pushed down, venting the cylinder.
- Add oil, closing the plug and so on.д.
This is done until all the air is out and the hydraulic oil comes out in accordance with the pumping of the brakes.
Extended service life
The failure of any tool is often an unpleasant and even dangerous experience, resulting in a loss of time and money. Failure of the elevator, at the most inopportune moment, can cause unnecessary problems, so it is recommended to pay increased responsibility when working with this tool. Fortunately, the operation and maintenance of a hydraulic jack is a short set of understandable rules that anyone can follow.
- When placing the jack under the load, make sure its base is firmly seated on a level, horizontal surface (floor, ground, asphalt). The surfaces of the stop and the load to be lifted must be parallel.
- The contact surface of the load should be as solid as possible, so it can support the entire weight of the load. In cars it is a stiffening rib, in private houses it is the walls with a padded bar.
- Lifting is done with smooth movements of the pump lever. The load must be in a stationary position, so there must not be any passengers in the vehicle. If the tool is completely lifted, the use of a safety cradle is recommended.
- When the jack is finished and the load can be lowered, check the rod for dirt and, if necessary, clean it with a rag to prevent corrosion.
- Store and transport the hydraulic jack only in the position designated by the manufacturer: upright for bottle and rhombic jacks and horizontal for rolling jacks.
- The piston rod, extension screw and pump piston must be lowered during storage. If you use the tool regularly, these elements should be lubricated periodically (as they dry out).
- If the operating-liquid is partly leaking or evaporating, the system should be topped up with identical oil and purged (process described above). It is strictly forbidden to pour water, acid and other mixtures! Only light hydraulic, heating oil or industrial oil.
The rules described above are the main foundations for confident and continuous operation of the tool. All jacks models have their individual features and characteristics that each manufacturer specifies in the documentation, which should familiarize every owner of these devices.
Hand tools Hydraulic tools Repair and modernization
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