The main malfunctions of the hydraulic jack
There are many varieties of lifting mechanisms, the most common among car enthusiasts is the hydraulic type of jack (bottle, rolling jack). Jacks can fail if not properly maintained, such as they stop lifting the load. And it immediately raises the question of what to do if the hydraulic jack doesn’t lift. It is not necessary to buy a new one at once, there is always a way out, often it can be corrected by doing maintenance of the aggregate.
- Stoppage. Occurs due to lack of fluid in the chamber or contaminants in the oil.
- Insufficient lifting height. Caused by a limited amount of working fluid.
- Slow, jerky lift. Because of the presence of air and possible leaks in the hydraulic system.
- Pressure drop. Need to diagnose the valve or replace it. In this case, the jack also stops holding, lifts fully, springs, can lower the load on its own.
The most common complaint on the forums is that the hydraulic jack does not lift.
Design and principle of operation
The design of hydraulic jacks is about the same for both jacking jacks and bottle jacks. The main parts of the jacking devices:
Shut-off valve actuated when crank is raised and oil flows into the chamber through the suction valve. By pumping oil from the tank into the cavity of the working cylinder the piston is raised. Then, to lower the piston with the piston rod, the bypass valve is opened, then the piston is lowered by the pressure of the load.
How the hydraulic jack works
For an accurate determination of the cause of the failure and its subsequent elimination, it is necessary to have a clear understanding of the principle of operation of the device. Fortunately, hydraulic jacks are quite simple, and most of their faults can be repaired by your own efforts. Appeal to the service may be necessary in cases of serious defects or complete lack of desire to familiarize with the repair manual. The basics of understanding the operation of the device, should be laid with the disassembly of the main components of its mechanism.
Before describing the functional elements, it is worth noting that hydraulic jacks have several subtypes and are divided into jacking, bottle and diamond-shaped. The bottle type is the closest to the classic type of liquid lifting mechanism, which includes devices with telescopic, hollow, hitch and standard rod. To give you an idea of the basics, let’s look at the original model without any further modifications. So, the hydraulic bottle jack, consists of the following components:
- Case base. Foot for mounting the unit on a flat surface.
- Housing. External part of the hydraulic jack and also the oil reservoir.
- Plunger cylinder. A sealed chamber, where the pressure of the fluid that pushes out the rod is created.
- Working plunger. Extendable element with end stop.
- Oil fill hole. Located in the upper, side of the instrument housing.
- Screw. Retractable element for increasing jack lift height. Screwed into plunger.
- Body head. Threaded joint securing the position of the casing to the cylinder.
- Sealing ring. Seals the oil reservoir, preventing fluid leakage.
- Screw nut. Top of body head with six faces for easy unscrewing.
- Lug. Handy element for transporting the jack by hand. Not available on all models.
- Screw head. Weight-topped end of rod.
- Lever. Hand pump detachable element that multiplies impact force. In most cases, includes a special groove for unscrewing the shutoff valve (more about it later).
- Displacement plug. Main element of the pump, driven by the lever. Pumps fluid from one reservoir to another.
- Pump cylinder. Sealed chamber and spacer in transferring oil between tanks.
- Stop valve. Used to connect/isolate oil reservoir to ram cylinder.
- Suction valve. Controls fluid flow inside the unit, allowing only one direction of fluid flow (only suction to pump cylinder).
- Relief valve. Opposite of suction. Allows the pump ram to squeeze oil out, but will not let it back in.
The essence of the device action is based on pumping liquid from an oil reservoir into a cylinder with a plunger. When the lever is raised, a portion of the oil is sucked into the pump cylinder, and when lowered, it is squeezed into the main cylinder of the jack. Due to this, pressure is generated in the main compartment, pushing out the piston.
The main thing is not to get air in the compartment, which can reduce stability and overall efficiency. Exactly for this reason, the bottle hydraulic jack does not work horizontally. However, even in this type of device there are models that allow lifting in different positions.
The main malfunctions and their causes
Among all the reasons why the hydraulic jack jack does not work jack, bottle or lozenge, we can distinguish 3 main variants: clogging of the system, valve failure or damage to the rod. These are the 3 building blocks on which the most common failures, resulting in reduced efficiency or total system failure, are based. For more clarity, let’s consider each case in more detail.
System blockage can be caused by air, dust or dirt in the fluid. In the consequence of the first variant, the jack stop may not rise, strongly spring or drop at all under the load. Accumulated clods of dirt, can restrict the movement of the valves, which will no longer close tightly, allowing the fluid to pass in both directions. In this case, the jack stand will not be fixed in one position and will gradually lower to the zero point. When figuring out why a hydraulic jack won’t hold, the first thing to look for is the cleanliness of the system.
Valve failure, in addition to clogging by dirt, can be caused by mechanical damage. The ball at the end of the spring, which rests in a cone-shaped groove, can disengage or become trapped in other parts of the structure. In that case, the piston rod will not rise at all, because fluid circulation in the system is impaired and pumping is not performed. This fault is more complex and requires disassembly of the device. It is not recommended to consider it before checking the system for blockages.
The piston rod can be damaged by failure to maintain or store it properly, by handling heavy loads or by improper use. In the first case, the piston may become corroded, reducing the tightness of the piston to the cylinder and causing fluid leakage. If you lift weights heavier than allowed, the stop may bend. The chances of this failure increase when the screw is fully extended and the jack is unevenly positioned on the ground. Stem deformation is considered to be the most serious breakdown, which is not always repairable even in special centers.
Having covered the main causes of faults, let’s move on to specifics. Let’s discuss the main problems and suggest solutions.
It does not hold under load
Stem deflation when resting on the load and even without excessive pressure can be caused by two things: insufficient oil or faulty valves. It is better to find out for sure, why the hydraulic jack is failing, from the simple to the complex. Let’s analyze each variant separately, according to the complexity of the repair procedure.
- Lack of oil is caused by trivial oil leakage if the valves are not hermetically sealed. May be a consequence of long storage of the tool with unscrewed shutoff valve or wear of gaskets. The problem is solved by refilling the fluid and pumping the jack. It is better to use a special hydraulic oil, but a simple industrial one will do. If after filling, fluid leaks, even when the valve is closed tightly, it is worth buying a repair kit and replacing all the gaskets.
- Failure of valves can be caused by clogging of the system or mechanical damage. If the hydraulic jack won’t hold, you don’t have to disassemble it right away. It is best to first flush the internal passages, which can become clogged with mud. To do this, drain all oil from the system and fill with flushing fluid (kerosene or gasoline are available). Pump a few times, drain and repeat the procedure a couple more times, using clean fluid.
If flushing is unsuccessful, you will need to disassemble the body and inspect the valves. They may be loose due to loose springs or worn balls. The first option is more likely and can be fixed by replacing the spring or putting a small washer under it to increase the pressure force by reducing the distance to the plug. Worn or chipped ball requires replacement. These can be found at the valve repair shop. kits sold in auto stores or take it out of a suitable bearing.
Not raising it well
One of the common problems encountered with hydraulic jacks is that the rate of extension of the rod is reduced to a minimum or completely to zero. This failure is often caused by a decrease in lift height and a reduction in maximum load. The main reason for such malfunction is in the ballooning of the system, which occurred as a result of a drop in the oil level. To restore the effectiveness of the device, in this case, is not very difficult. You will need some oil (150-300 ml) and flushing fluid (if the tool is more than 2 years old).
- First of all loosen shutoff valve by 1 turn from tightened position. Then lower the pump piston and stop to the zero point.
- Unscrew or remove (if rubber) the plug on the fill hole and drain the old oil into any container.
- If the device is several years old, it is likely that its internal channels could be clogged with dirt, which can be just as good a reason why the hydraulic jack is bad lifts. It is advisable to flush the device, preferably several times. For this you can use kerosene or gasoline. Simply pour the liquid through the hole from where you poured the oil, close the valve, pump up the stop, open the valve, lower the stop and repeat the process two times. Then we pour in new and clean oil and repeat the above mentioned procedure at least one time (cleanliness of the drained oil should be looked at).
- When you are sure the system is clean, you can fill it with oil. Almost all varieties can be used here, except brake fluid. Make sure that the consistency is not too thick. Preferably use special hydraulic oil or synthetic industrial oil.
- Before pouring in oil, lower the pump piston and stop to the zero position and screw in the valve. If the jack is a bottle jack, while filling it should be set in a vertical, working position (a rolling jack is filled in the horizontal position).
- It is more convenient to fill the jack with liquid through a syringe, slowly pouring the liquid until it fills the whole volume of the reservoir and starts to flow out of the hole.
- After completing the filling, it is necessary to pump the system by expelling the excess air from it. To do this, with the fill hole open, pump oil from the reservoir to the cylinder. When the jack will reach the maximum height, unscrew the stop valve and lower it. Repeat this procedure 2-3 times.
- There is another way of pumping, without using a pump, if the previous one did not work. You should unscrew the stop valve for 1-2 turns, then pull out with your hand and immerse the rod into the cylinder, each time reducing the height of lift by 1 cm, until you reach the zero mark.
The hydraulic jack is not lifting what to do?
There are many varieties of lifting mechanisms, the most popular among car enthusiasts is the hydraulic type of jack (bottle jack, jacking jack).
Jacks may malfunction if improperly serviced, for example, they stop lifting a load. And immediately the question arises, what to do if the hydraulic jack does not lift.
It is not necessary to buy a new one, there is always a solution, often it can be corrected by doing the maintenance of the unit.
Briefly about the main faults
Hydraulic jackMalfunctions can be different, but have one common cause.
- Stoppage. Occurs due to a lack of fluid in the chamber or the presence of contamination in the oil.
- Insufficient lifting height. Occurs due to a limited amount of working fluid.
- Slow lifting, jerking. Due to the presence of air as well as possible leaks in the hydraulic system.
- Pressure drop. Valve diagnosis or replacement is needed. In this case, the jack also stops holding, lifts fully, springs, can lower the load on its own.
Most often on the forums you can meet complaints that the hydraulic jack does not lift.
Specialists recommend a good study of the lifting device, the scheme of its operation, because the presence of faults or improper operation of the unit can cause serious injury to man or damage to the lifted cargo.
Design and principle of operation
The design of hydraulic jacks is much the same for both jacking jacks and bottle jacks. The main parts of the jacking devices:
The load should be lifted with the unit on a level plane. When a person presses down on the handle, the piston rod builds pressure, as a result of which the valve is actuated and the oil flows into the working cavity (chamber).Dirt on the valve
Shutoff valve is actuated when handle is raised and oil flows into the chamber through the suction valve. The piston is lifted by pumping oil from the reservoir into the chamber. Then, to lower the piston with the rod, the bypass valve is opened, then the piston is lowered by the load pressure.
That is, to lower the rod with the load it is necessary to slowly unscrew the drain valve located on the body of the jack.
Why the jack will not lower or raise
The reasons why the jack refuses to work:
- Cylinder failure. The working plane cannot hold the load, and as a result, the fluid flows from the cavity to the piston head space.
- Mirror damage. The hydraulic system loses efficiency or simply fails, this is caused by improper transport, it can lead to oil leaks and air getting into the chamber, in this case corrosion will definitely begin with time.
- Corrosion. Wears jack seals and packings soon, possibly contaminates fluid and clogs ducts and valves.
- Falling of the unit. The higher the height from which the jack falls, the more serious may be the deformation of parts, major components.
- Excessive load. Causes the piston rod to bend. Leads to distortion of major components and loss of oil.
- Improper use of the unit and untimely oil changes.
Oil leakage is the main problem that causes the jack not to lift until the end (with a small leakage) or at all (with a significant). Because of this air enters the cavity, the jack works at a reduced power or refuses to work at all. Leakage in the hydraulic system can be prevented by scheduled maintenance, checking the oil level. In the case of a low level, you just need to add liquid to the norm.
Oil level loss can occur naturally or as a result of worn or damaged oil seals and collars. You won’t get away with just adding oil, you’ll need to replace the o-rings.
Because of the lack of fluid air is leaking into the hydraulic system.
This problem is solved by pumping: you need to unscrew the plug of the oil tank and bypass valve, and then just pump the system, that is, move the lever up and down until the liquid flows into the main cylinder.
Corrosion on the pistons, rods, and cavity of the jack is often the cause of malfunction. To determine the cause and repair in detail, the unit will have to be disassembled.
A bent rod is also a common reason why the jack does not lift or jerks. In this case, you can change the element with an analogue from an older model, or buy a new part.
In most cases such a fault cannot be repaired at all, even in a workshop or service center. This is because usually the piston rod is bent by impact loads and in this case the main body elements are damaged.
In this case it is cheaper to buy a new unit and not to repair or replace parts.
It is better to remove the dirt with kerosene.
When the bypass valve becomes deformed or just has dirt accumulated in it, the ball of the valve sits tightly in its seat and hydraulic fluid leaks through it. In this case, you will simply have to replace it and change the old (contaminated) oil with the new one.
The piston rod extends to the required height, but then slowly (without affecting the load) descends. in this case, the cause is most likely in the bypass valve and damaged O-rings, so the required pressure is not maintained.
If the jack does not come up to the end, it means that working stroke decreased. At this point, the culprit is corrosion on the rod and the mirror of the cylinder surface. If the load to be lifted exceeds the jack capacity (indicated in tonnes in the certificate and on the body), the jack is likely to be damaged or bent.
If jack does not return to the top of its starting position when the pressure relief valve is opened, it means that springs are stretched or have lost their springing ability.
Repair and pumping of the hydraulic jack with your own hands
Today it is impossible to imagine carrying out car repairs, whether it be wheel replacement or suspension repair, without using jacks. special devices that are designed to lift cargo and fix it at a certain height. And today the most popular are hydraulic jacks, where the force is created by a piston and a working fluid.
Hydraulic jack design
The main elements in the design of the hydraulic jack are:
The hydraulic jack may have a regular or extended body made of hardened metal. The housing has the following functions: it is the reservoir for the operating oil and acts as a guide cylinder for the piston.
This unit is equipped with an air-, foot-, or hand-operated hydraulic pump. Jack design includes safety valves and other devices to maintain failure-free and durable operation.
The retractable hydraulic cylinder and the lifting mechanism, which raises a special platform, are located in the openings of the housing. Lowering is performed by rotating the T-handle. The design has built-in wheels, which ensures mobility of the unit. The extended body of the jack is usually used to work with heavy vehicles and buses.
How it works
All hydraulic jacks work by using fluid in communicating vessels. Before jacking, set the jack on a firm and level surface under the car and, with the valve closed, squeeze the lever until the car reaches the desired height. The machine is lowered by opening a valve on the jack body.
Operating hydraulic oil is pumped through the drive pump by means of the lever. The liquid is forced through a valve into the cylinder. Two valves, one suction valve and one discharge valve, prevent oil from flowing back out. To lower the jack, open a valve on the pump, in which case the fluid flows from the cylinder back to the housing.
Presence of threads on the body, protected by a special casing, threaded holes in the base and threads on the stem, guarantees unlimited operation of jacks and possibilities of use for bending, clamping and crimping. Rugged support made of hardened metal and mounted on the piston rod protects the lifting mechanism from damage. Ribbed base plate prevents the vehicle from slipping.
Advantages and disadvantages
Hydraulic jacks are considered to be the most unpretentious. The hydraulic system is characterized by an incompressible hydraulic fluid. The result is smooth lifting, precise braking and a perfect fit. Hydraulic jacks have an excellent efficiency of up to 85% and a high lifting capacity of over 250 tonnes at low forces, thanks to the high ratio between the cylinder and pump ram surfaces.
But hydraulic lifting devices have a much higher initial lifting height, unlike mechanical devices. Another difficulty is the inability to precisely adjust the height of lowering. To keep the jack in operating position, you need to check the glands and valves for leaks at all times and keep an eye on the oil level. These units can only be stored and transported vertically, otherwise the fluid can spill out of the housing.
Disadvantages of the hydraulic jacks:
- Are quite slow.
- Large size and weight.
- High price.
- Short stroke for single-plunger jacks.
Bottle (vertical) jacks
Hydraulic vertical jack is the simplest design. The range of applications for these jacks is quite extensive due to the significant range of loads to be lifted, from 3 to 200 tons. Bottle jacks are used in trucks. In addition to the main advantages of the hydraulic jack, the bottle jack models have several other advantages, such as a large support area, compactness and versatility of use.
The vertical jacks can be double-rod and single-rod. The single-rod device is characterized by ease of operation and simple design, which expands the scope of its use and makes it possible to perform work of varying complexity:
- for dismantling and mounting in construction and mechanical engineering;
- repair of car and automobile wheels;
- use as a power unit for pipe cutters, pipe benders, presses, and similar tools.
The two-pin telescopic jack is of similar design to the vertical jack, the operating principle of the bottle mechanism is based on installing several rods. The piston is located at the base of the telescopic device. It can be used in vertical and horizontal position. It fits most cars and has small dimensions. Lifting is performed by means of a lifting arm, which is driven to the operating position by a cylinder.
This type of jack works on the same principle as the vertical jack, but with the difference that the cylinder is not in the vertical position, and the piston is not directly aligned with the jack. This device is called a jack due to the fact that it is a cart on wheels, which can be rolled on the surface. The jack moves or “rolls” under the load while lifting the arm and picking up.
This jack is set in motion, as well as bottle jacks, by the rocking lever, also lowers. by unscrewing the screw of the valve. If it is necessary to lower the load, it is necessary to put a tubular handle on the valve screw, then the bulkhead fits into the groove of this screw. By turning the handle around the axis, the operator also turns the screw, thus reducing the pressure in the cylinder and lowering the car to the desired height.
As a rule, the jack is used at the tire fitting station, as it is ideal for lifting one side of the car, quite fast in installation and operation. The disadvantages of this design come from the name. to work the jack needs a solid and flat surface, asphalt or concrete. In addition, the large weight and size complicate the transportation of the device in the car.
Repair: What to do if the hydraulic jack does not lift?
The hydraulic jack is the most common and useful lifting device in the world, and malfunctions of the hydraulic jack can be an unpleasant surprise.
The jack is used in so many different applications that it is impossible to mention all of them. This is because the ways and purposes of its application are limited only by your creativity and imagination. Mostly hydraulic jacks are used in the following areas:
For lifting-lowering of cars, trucks and special vehicles. Almost every car owner has a hydraulic jack with a 2 to 3 ton capacity. All car service centers have hydraulic jacks in their arsenal. This simple mechanism will easily lift your car.
When doing construction work. You need to lift a structure or building. no problem. Only it is necessary to take into account the maximum capacity of the jack, which should not be less than the load to be lifted. So, why won’t the hydraulic jack hold??
Repair of mobile hydraulic jack in case of failure, why the hydraulic jack doesn’t hold? How to Repair a Hydraulic Jack?
The hydraulic jack does not work the reasons:
It often happens the situation that the hydraulic jack does not lift and it is not clear what to do. If the hydraulic jack doesn’t work, what could be the causes. Let’s try to solve this situation.
Hydraulic lifting devices periodically need maintenance, that’s why the working cylinder needs to be filled with oil, which flows out during the operation through all kinds of seals and glands.
Some signs of a hydraulic jack malfunction:
Cause: Jack’s bypass valve is defective or sleeves have failed. That’s why the pressure isn’t holding.
- The hydraulic jack fails to lift the load or lifts it only to a small height, t.е. There is a decrease in the working stroke, the hydraulic jack is not working causes.
Hydraulic jack failure reason: corrosion on the piston rod and inside of the cylinder housing. If a load exceeding the maximum permissible weight for this unit is lifted, a distortion of the rod may have occurred.
The reason for the failure of the hydraulic jack: stretched or lost its elasticity springs.
The hydraulic jack does not lift. the main causes of malfunctions of the hydraulic jack and ways to fix them:
One of the most common causes of jack failure, if the hydraulic jack does not work, can be an oil leak. As a result, the air enters the working chamber, and, as a consequence, the lifting mechanism does not work in full force or ceases to function. This is the answer to the question of why the hydraulic jack does not hold.
It is possible to avoid such problems by periodical hydraulic jack maintenance, which consists in checking liquid quantity and refilling of working cylinder, if necessary. The reduced amount of oil in the system may be due to natural attrition, but also due to damaged or faulty seals and packings. In this case, the usual topping up of the fluid will not solve the problem and the defective seals and packings must be replaced.
Lack of hydraulic oil in the system, air is replacing the hydraulic oil. you may tell by the reduced jacking performance. You can get rid of the problem by pumping. But if that doesn’t work, either the cause of the malfunction is different, or more serious repairs will be needed.
Corrosion can often cause a hydraulic jack to fail, affecting the pistons (rods or plungers) that are retracted and the inside of the housing. But to find out the reason, you will need to disassemble the machine. To do this, you can go to a service shop.
The bent rod also often becomes the reason of failure of the jack, in this case, if the design features of the model provide, it can be replaced with a new one, but often it means that the jack can not be repaired even in the service shop.
Sometimes there is dirt in the working chamber, which may also cause the jack to malfunction. The hydraulic jack does not lift what to do? The hydraulic jack doesn’t work?
How to repair the hydraulic jack, if the hydraulic jack does not hold the reason or the hydraulic jack does not work. causes?
How to Repair a Hydraulic Jack? It can be done in the following way: you can remove the dirt by washing it with kerosene. A jack’s bypass valve can also quite often be the culprit. Relief valve of the jack may have some deformation, or dirt may get in it that results in the ball not being tightly seated and, consequently, the fluid flows out. This problem is solved mainly radically. the overflow valve of the jack is replaced with a new one.
Where to repair a hydraulic jack, if the hydraulic jack does not work?
In the case of failure of hydraulic jack LLC “GidroSpetsTech” performs repair of hydraulic jack and area (jack, bottle, industrial hydraulic jacks) of different manufacturers. Repair of pipe benders and puller repair.
Methods of troubleshooting
Oil leakage is the main problem that causes the jacking jack not to lift all the way (with a small leakage) or at all (with a significant leakage). Because of it the air gets into the cavity, and then the hydraulic 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 case of a low level, just add fluid to the norm.
Decrease in oil level may be due to natural causes, as well as due to wear or damage of seals and cuffs. You won’t get away with just adding oil, the o-rings must be replaced.
Air is leaking into the hydraulic system because of lack of fluid. This problem can be solved by pumping: you need to unscrew the plug of oil reservoir and overflow valve and then just pump the system, that is move the lever up and down until the liquid flows into the main cylinder.
Corrosion on the pistons, rods and cavity of the jack is often the cause of malfunctions. To determine the cause and repair in detail, the machine must be disassembled.
Bent rod is also a common reason why the jack does not lift or works with jerks. In this case you can either replace the element with an old one, or buy a new one. In most cases it cannot be repaired at all, even in a shop or service center. This is because the stem usually bends when subjected to shock loads, and in this case the main body elements are damaged. In this case, it is cheaper to buy a new unit and not have to rebuild or replace individual parts.
It is best to remove the dirt with kerosene.
When the by-pass valve becomes deformed or has dirt accumulated in it, the ball of the valve sits tightly in its seat and hydraulic fluid leaks through it. In this case, you need to replace the valve and change the old (contaminated) oil for the new one.
Changing the oil
Repair and Maintenance.
In order to service a bottle jack it must be disassembled. You don’t have to worry about splashing yourself with oil from the high pressure. It is quite possible to do this operation by yourself. The first thing to do is to drain the oil. Drain through the filler hole or through the by-pass valve if it is absent, unscrew the upper hex nut and completely unscrew the lower cock. Remove the body, check its tightness, assess the condition of the lower rubber ring. These parts don’t have any load, they’re just a reservoir for the fluid. Next, unscrew the operating cylinder and remove the piston. We thoroughly inspect everything for rust. In case of its detection get rid of it as carefully as possible. Unscrew plug and check its performance, inspect o-rings. There must not be any iron chips inside, parts must not have any dents. Replace defective seals with new ones. Do not forget to thoroughly rinse all valves from dirt and deposits. Assemble, that’s all the repair is done.
Repair and service.
To service the bottle jack it needs to be disassembled. There is no need to worry about splashing yourself with oil from high pressure. It is quite possible to do this operation yourself. The first thing to do is to drain the oil. Drain through the fill hole, if it is absent through the by-pass valve, unscrew the upper hex nut and completely unscrew the lower cock. Remove the housing, check its tightness, assess the condition of the lower rubber ring. These parts do not carry any load, it is just a reservoir for the liquid. Then unscrew the working cylinder and remove the piston. Examine everything carefully for rust. If there is any, get rid of it as carefully as possible. Unscrew the ram, check if it is working properly, inspect the o-rings. Inside there should be no iron chips and no dents. Worn out seals should be replaced with new ones. Do not forget to thoroughly wash all the valves from dirt and various deposits. We assemble, that’s all the repair is made.
The first mentioned, the most common and known are the bottle-type jacks, they are often (by the most classic application) called car jacks.
Most companies start with one and a half ton modifications and up to 15-20 ton modifications. They are simple in design, compact in packing and unpretentious in service, they are capable to serve a diligent car owner faithfully for many years.
Actually, maintenance, in most cases, is reduced to checking the oil level, topping it up if necessary, and periodic idle running of the jack, so that during operation all its parts could be lubricated, the springs could work and the balls of the bypass valve could turn, which would prevent their sticking due to rare operation and would not lead to inoperability of the device in a critical situation.
Just because of the possibility of oil leakage, it is still better to store bottle jacks in an upright position.
Repair of such jacks is very rare, but if the jack is working on wear and tear. for example, at a service station or other production, it is most often reduced to replacement of the piston and plunger collars, rubber seals, less often. springs and balls of the bypass valve.
Recommended: Plastic decorative corners for trimming arches
Advantages of the bottle hydraulic jack:
compactness; stability; durability; low applied force; universality of use. except for vehicles, these jacks are used in construction, railway transport, as a power unit for pipe benders and pipe cutters; easy to repair.
These jacks are the main and almost non-alternative on trucks.
The jack is not allowed to work in an upright position because of: its high initial height; low lifting height; it cannot be raised in an unverted position.
Nowadays car hydraulic jacks are produced in convenient compact packing, making their stowage and storage in the car, especially on long trips, very convenient and accurate, preventing the damage of things transported in the luggage compartment by the possible ingress of oil.
By the way, the shape of the drawers and the location of the handles hints transparently at the vertical storage of bottle-type jacks. A hydraulic jack is devoid of these drawbacks, but it is more expensive and less compact, but as a car jack is not inferior to the bottle jack, and in some cases surpasses it:
When working on sites that have a slope; has a much lower pickup height; easier to move and set under the car thanks to the wheels; has a greater lifting height (from 300 to 400 mm).
We would recommend jacks for cars driven by women.
One more, in our opinion, interesting model of car jack is created on connection of two types of this device: rhombic screw and hydraulic. It is certainly a hydraulic jack, but its force is transmitted by levers to the rhombic lifting device, which has undeniable advantages:
low lifting height; absence of deviation in the vertical plane during lifting; high lifting height.
We would be wrong if we do not mention some less well-known, but no less useful representatives of hydraulic jacks.
How the hydraulic jack works
In order to accurately determine the cause of the failure and its subsequent elimination, you should have a clear understanding of the principle of operation of the device. Fortunately, hydraulic jacks are designed quite simply, and most of their faults can be eliminated by your own efforts. Contact the service may be necessary in cases of serious defects or a complete lack of desire to read the repair manual. The basics of understanding the operation of the device, should be laid with the disassembly of the main components of its mechanism.
Before describing the functional elements, it is worth noting that hydraulic jacks have several subtypes and are divided into rolling, bottle and diamond-shaped. The bottle type is the closest to the classic type of hydraulic lifting mechanism, which includes devices with telescopic, hollow, hitch and standard rod. To form a correct basic idea, let’s take apart the original model without additional modifications. So, the hydraulic bottle jack, consists of the following components:
- Body base. Supporting platform for mounting the device on a flat surface.
- The Case. External part of the hydraulic jack and, at the same time, the oil reservoir.
- Plunger cylinder. A sealed chamber where the pressure of the fluid that pushes the rod out is created.
- Working plunger. Retractable element with a stop at the end.
- Port for filling up oil. Located in the upper, side part of the body.
- Screw. Retractable element for increasing jack lift height. Screwed into plunger.
- Body head. Threaded connection securing the position of the housing to the cylinder.
- O-ring. Seals the oil reservoir and prevents leakage.
- Screw nut. Top of housing head with six faces for easy unscrewing.
- Earring. Handy element for transporting the jack by hand. Not available on all models.
- Screw head. Plunger end resting against load.
- Lever. Removable hand pump element that multiplies impact force. In most cases, includes special groove for releasing shutoff valve (more about it below).
- Plunger. The main element of the pump, driven by a lever. Pumps fluid from one reservoir to another.
- Pump cylinder. Sealed chamber and intermediate in the transfer of oil between the tanks.
- Stop valve. Serves to connect / isolate the oil reservoir with the ram cylinder.
- Suction valve. Regulates fluid movement within the unit, allowing it to flow in one direction only (suction to pump cylinder only).
- Relief valve. Opposite of suction. Allows pump plunger to squeeze oil out, but does not let it back in.
The function of the device is based on pumping fluid from the oil reservoir to the ram cylinder. When the lever is raised, the oil portion is sucked into the pump cylinder; when lowered, it is squeezed into the elevator’s main cylinder. This creates pressure in the main compartment, pushing out the piston.
The main thing is to ensure that no air enters the compartment, which can reduce stability and overall performance. It is for this reason, the bottle hydraulic jack does not work horizontally. However, even in this type of device, there are models that allow you to lift in different positions.
How to troubleshoot and pump the jack with your own hands
Using jacks is effective if you know how to pump the jack. Nowadays, it is impossible to carry out car repairs if there is no jack. This is a special device, with the help of which it is possible to lift loads of great weight. To provide the working force of such a mechanism involves a piston that has a hydraulic fluid.
Design and operating principle of the hydraulic jack.
The bottle jack is used for wheel replacement, which makes it possible to repair the suspension of the car. There are the following types of jacks: retractable (rack) or jacking. The vertical extension of the mower jacks is made with a cylinder, one or more. Height of extension of the rack jack may vary.
The hydraulic jack has a different design. The metal body of the device is mounted on four wheels, which are necessary for the movement of the mechanism. A hydraulic cylinder with a lifting mechanism is attached to its openings. The platform is raised by a special cylinder that extends horizontally.
What are the elements of the hydraulic jacks?
The lever of the device allows the pump to actuate, pumping the hydraulic fluid into the cylinder through a special valve. The hydraulic or working fluid is the oil squeezed into the cylinder. The jack is lowered back when the valve located on the pump is open so that the hydraulic fluid flows into it.
The hydraulic jacks are easy to use. They must be located on a level ground surface under the vehicle. After closing the device valve, its lever is pressed until the car is raised to the desired height from the surface.
To lower the vehicle back to the ground when the wheel is already replaced, the valve opens smoothly counterclockwise. When the unit is in its original position, the valve is closed back by turning it in the opposite direction.
The jack, like any mechanism, requires periodic inspection and maintenance. Liquid can be refilled in the cylinder, since the use of the device is associated with oil leakage through the seals as well as the oil seals. When using the jack to repair the vehicle, use the jack stand. By adjusting the device with it, it is possible to prevent the vehicle from falling to the ground in the event of a jack malfunction.
Storing the unit in places where there is excessive moisture will cause the cylinder to rust. For the same reason, the working cylinder can fail. At the same time, the disadvantage of the hydraulic jack is the slow speed of operation and low lifting height. Some models have a sufficiently large empty weight, so it is not very convenient to transport it in the trunk.
Scheme of filling the hydraulic jack with oil.
Among the advantages of jacks are rigid design, as well as the height of the lifting load from the ground, the greatest lifting capacity with smooth running, the minimum pick-up height. All these advantages give high efficiency.
Causes of failure of equipment can be any. For example, long operation of the device may cause air accumulation in the form of bubbles. It reduces the efficiency of using the jack, that is, its efficiency drops dramatically. It occurs due to air entering the hydraulic mechanism because of the lack of hydraulic fluid.
To bring the device to its original state will allow the performance of the following actions:
- The jack should be started with the by-pass valve and oil reservoir cap open.
- Pump the unit pump a certain number of times, which will displace all the accumulated air from the working cavity in a special container for the fluid.
- Close the oil tank opening and the by-pass valve.
If all the operations are performed correctly and the air is purged, the unit should work properly.
Otherwise the above steps are repeated according to the instructions.
Corroded parts should be replaced.
As the above method of pumping the jack is not the only one, it is possible to perform the following actions step by step:
- If the jack is slow to lift or is completely defective, determine the presence of air in the cavity of the device.
- The locking needle should not be unscrewed by 1.5-2 turns, and the jack plunger is raised by the screw to the upper point, which is the extreme point, and then lowered again to return it to the bottom position.
This last operation should be repeated 2 or 3 times. To prevent this problem, check periodically the level of liquid in the jack. If it is insufficient, the oil must necessarily be topped up.
Pumping of the jack is to be repeated after impurities get into the working cavity. Unscrew the body cap, then pour kerosene into the base of the body to remove the contaminant. Then the jack is pumped by previously unloading the blocking 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:
- Fill up with oil and close the box.
- The piston should be pumped by raising it to failure.
- The plug is unscrewed and the piston is pushed down, venting the cylinder.
- Add oil, closing the cap, and so on.д.
This is done until all the air is out and the hydraulic oil comes out in accordance with pumping the brakes.
The hydraulic jack is difficult to replace in order to lift and hold the equipment. There are different signs that indicate failure of the equipment. For example, it is difficult to lift a load, and the level of lift to height may be significantly reduced.
A large number of strokes may need to be made to position the device at the desired height. If the hydraulic jack does not go down, this is a clear sign that it is broken. To make a decision on the choice of pumping method will help to know some breakdowns. These include:
- The presence of rust inside the device, limiting the process of lowering the mechanism to the desired position.
- Excessive load experienced by the device, which causes the rod to bend.
How to troubleshoot and pump the jack with your own hands
The use of jacks is effective, if you know how to pump the jack. Today, you can’t repair a vehicle if you don’t have a jack. It is a special device with which heavy loads can be lifted. In providing the working force of such a mechanism involves a piston that has a hydraulic fluid.
Design and operating principle of a hydraulic jack.
The jack is used for wheel replacement, it makes it possible to repair the suspension of the car. There are the following types of jacks: retractable (rack) or jackstand. Unit jacks extend vertically with one or more cylinders. The extension height of the jack may be different.
The carriage jack is a different design. The metal body of the device is mounted on four wheels, which are necessary for the movement of the mechanism. In its holes strengthen the hydraulic cylinder, which has a lifting mechanism. The lifting of the platform is achieved by a special cylinder that extends horizontally.
What are the elements that make up the hydraulic jacks?
The lever of the device drives a pump that pumps the hydraulic fluid into the cylinder through a special valve. The hydraulic or working fluid is the oil squeezed out in the cylinder. The jack is lowered back down with the valve located on the pump open to allow the hydraulic fluid to flow into it.
Hydraulic jacks are easy to use. They must be located on a level ground surface under the vehicle. After closing the device valve, its lever is pressed until the vehicle is raised to the desired height from the surface.
To lower the vehicle back to the ground when the wheel is already replaced, the valve is opened smoothly counterclockwise. When the device is in its original position, the valve is closed back by turning it in the opposite direction.
How to properly pump a jack
The jack, like any mechanism, requires periodic inspection and maintenance. Liquid can be refilled in the cylinder, as the use of the device is associated with oil leakage through the seals, as well as glands. Use jack to repair the vehicle using jack stands. By adjusting the device with it, it is possible to prevent the car from falling to the ground in case the jack is defective.
Storing the unit in areas where there is excessive moisture will cause the cylinder to rust. For the same reason the working cylinder can fail. However, the disadvantage of the hydraulic jack is the slow speed of operation and low lifting height. Some models have a sufficiently large empty weight, so it is not too convenient to transport it in the trunk.
Instructions for properly pumping the jack device
Filling scheme of the hydraulic jack with oil.
Among the advantages of the jacks stand out a rigid design, as well as the height of lifting the load from the ground, the greatest lifting capacity with smooth running, the height of pick-up minimum. All these advantages give a high level of efficiency.
Types and Causes of Failures
The hydraulic jack can be repaired with your own hands. All possible faults and the rules for rectifying them are known. Parts are prepared in advance. for replacement of defective ones. The main causes of breakdowns and the rules for their elimination are known. For this you need to have the right tool at hand.
Hydraulic cylinder failure
If a hydraulic cylinder malfunctions, the oil reservoir must be removed. First disconnect the piston. To do it with a wrench unscrew the screws located in the upper part. Protective rings are removed, the reservoir is pulled out. If the cylinder is damaged, it is replaced. The installation process will require the presence of a clamp. Screws that have been unscrewed from the jack are replaced with new ones. They are matched to the same size. If the bushings that were removed are worn out, new ones will be installed. Some models allow the use of a round type.
Upper and lower ring protrusion
If the top ring has protruded, the top plate must be removed. Inspect it beforehand for any defects. Screws are unscrewed with a wrench. It is important to inspect the piston and make sure that the broken ring has not damaged it. After that, a new one is installed on the piston rod. Sealant should be used to improve hold-down.
If the lower ring has protruded, the lower frame is removed. In this case, the hydraulic cylinder is inspected. Check its integrity. It is important that the piston moves smoothly, without jamming.
To remove the frame, the jack is turned upside down and secured securely. The cover is removed only after the o-ring is inspected. Use a screwdriver to remove the extension arm. It also needs to be inspected because there is a risk of damage from the ring.
If it is replaced, the markings on the body or written in the documentation are checked.
the rod is lubricated with machine oil during installation. A new ring is also fitted.
Breakage of the traction arm
The complexity of this repair is that you need to remove both the traction device and the cylinder. First the top cover is removed and the cylinder is inspected. There may be scratches on it. Sometimes the movable plate also needs to be replaced.
The cylinder is removed using a clamp, and the top plate is held on the rods. If the design contains several pistons, removal of the coil is also required.
The pulling device with the connected lever is on the lower plate. To remove the lever, use a hammer to loosen the rod. As the last step, the lever is secured to the pulling mechanism.
Breakage of the wedge gripper
In the case of such a breakdown, the top plate is disconnected. To do this, unscrew 4 screws. Use a screwdriver to pick up and remove the coupler. Located near the oil system.