The Top 10 Reasons for Hydraulic Cylinder Failures – And What to Do About

Hydraulic Cylinders and Actuators

Hydraulic cylinders fail for a wide range of reasons from bad specification and misuse to just plain old age. Here are the top 10 reason failure and how to go about the hydraulic cylinders repair.

Hydraulic Cylinders – Supply Center


1 – Regular seal leakage

This can be caused for a number of reasons the most common of which on new cylinders is incorrect fitting of the seals, however incorrect metalwork clearances may also cause early stage failure. Another physical reason for this failure once the device is in use is corroding, or marking of the seal grooves. The oil itself may also be the cause either because it is contaminated, or else because air has been trapped.

Corrective measures unsurprisingly include checking and if necessary replacement of the seals. Metalwork clearances should be checked in any event and if the oil is found to be contaminated then it should be replaced. There needs to be a clear reason established for oil contamination as it may be a sign of less obvious wear – checking clearances is part of this process.


2 – Piston rod scored

Scoring of the piston rod is often caused by oil contamination, but this may also be contamination of the gland bearing. If not caught in time then the gland bearing may have failed completely.

The gland bearing needs to be checked and replaced if necessary. The entire hydraulic system will need to be flushed and all filters change before re-assembly and re-pressurising.


3 – Cylinder bore scored

Scoring of the cylinder bore can also be caused by contamination of the oil, which may in turn be a sign of piston head bearing failure.

The piston head bearing will need to be checked and replaced if necessary. For either failure reason, the entire hydraulic system will need to be flushed and all filters change before re-assembly and re-pressurising.


4 – Barrel internally corroded

The most likely cause of a barrel being internally corroded is water in the oil.


Correction may require disassembly and re-coating, but as a minimum the oil will need be changed. The hydraulic cylinders will need to be protected from future water ingress and this may also be a sign that it is either wrongly specified or perhaps being used in an environment for which it was not designed.


5 – Piston rod pitting

Pretty much the only cause for piston rod pitting is corrosion. This may also be a sign that the hydraulic cylinders are either wrongly specified or perhaps being used in an environment for which it was not designed.

To begin with the rod and even the whole cylinder should be protected from the weather or any other reason for contact with water. Ideally the rod should also be upgraded to marine specification.


6 – Leaking from around the gland outer diameter

Leaking from around the gland outer diameter can be caused by o-ring failure, or by having a cracked gland, either which in turn could have been caused by poor clearances.

Clearances will need to be checked and the gland tested for cracks. If the o-ring is faulty then a backup can often be fitted, or the o-ring can be replaced.


7 – Bent piston rod

A bent piston rod may be a sign that the hydraulic cylinders is a being overloaded. This may be because the cylinder and associated piston are working outside of their specification – overloaded in other words. It can also be caused by an outside (sideways) impact of some kind – for example a collision.

The first thing to check is the load and whether the cylinder is working within specification, or not, as without this information any repair will not last long. The piston rod can be replaced, but this is also an opportunity to review the specification and upgrade the rod if necessary.


8 – Split weld on base and ports

A split weld on the base and ports may be caused at the original manufacture (or recent repair) by a poor weld failing. It may also be caused by shock loading – or a sudden impact to full pressure (or beyond).

An examination of the use of the cylinder is required to make sure it is not being misused, or employed out of its specification. This will ensure the problem does not recur after repair.

Repairing will involve machining off the weld and re-welding correctly.


9 – Eye bearing broken

A broken eye bearing is usually caused by the hydraulic cylinders working on a load above its specification, or else by a shock loading – or a sudden impact to full pressure (or beyond).

As with other issues above, before a repair is made the operational use of the cylinder should be checked to ensure it is not working out of specification. This investigation can lead to a change of use, or else an upgrading of specification on repair. For example, the specification of the replacement eye bearing may be upgraded and the clevis pin size may also be increased.


10 – Rod worn on one side

A rod worn on one side is a sign of a sideways movement of some kind either from a lack of bearing support (perhaps from bearing failure), or else too much side load which can be a result of misalignment or misuse. The rod itself may actually be under specified for the load and so the use of the cylinder should be checked to make sure it is being used within specification.

A repair will provide an opportunity to not just fix the problem, but raise the specification of the assembly by increasing the rod size, increasing the bearing area or incorporating external guides. A combination of all three is also possible.

The above list is not exhaustive of course, but these are the most common failures. Often a hydraulic cylinder repair is an opportunity to review working practices, or raise the specification of the hydraulic cylinder. This means that not only is the problem fixed but preventive measure applied to reduce the possibility of future recurrence.

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Important Parts of Hydraulic Cylinders and Their Roles by

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Generally Hydraulic cylinders are the mechanical parts that are used in many types of production units for transmitting power. The machines used in these manufacturing units provide linear force in one axis either in one direction or both the directions. Inside the cylinder, Pressure of the oil acts against the surface area of a piston to produce motion.

Hydraulic cylinders in India

Car-CarriersThese cylinders are on stage a foremost role in best of the applications. Most of the car parts and heavy machineries can be easily operated by using the principles of hydraulic. In addition to these, there are many other equipment’s and machineries like elevators, excavator, injection moulding machines, bulldozers and many other automobiles. For any industry, hydraulic cylinders are considered as a workhorse to produce their desired amount of production. They make the function of any production unit very easy and smooth. They are the simplest form of machines that are used to transfer effective power to many different types of machineries and automobiles. They are available in different types that include heavy duty industrial cylinder, tie rod cylinder, hydraulic cylinders with front flange mounting and many others. They are also available in different types of sizes that suit the requirements of different types of industries. Moreover, there are many hydraulic cylinder suppliers who are providing effective custom services for their clients. On request and just by paying additional charges, they allow their clients to customize their products with respect to their needs and requirements.

Important parts of hydraulic cylinders designed by

But it is essential for any production unit to understand the functions, operating systems, structure and parts of the cylinder in order to gain full advantage of the cylinder. A simple type of cylinder is generally made from 5 different parts including tube, piston, rod, gland and end cap.

Tube: In a typical hydraulic cylinder, the tube is one of the main parts of the cylinder. All the process happens within the tube, as it acts as the covering agent for the cylinder. It helps the fluid to remain inside the cylinder and disabling it to flow outside.

Piston: the piston is the inside part of the cylinder that pushes against the fluid. This is the most important part of the cylinder. Without a piston, hydraulic cylinder will be considered as just a cylinder. The diameter of the piston is known as Bore. The cylinders with larger Bore can do more lifting with ease. Therefore for a higher lifting capacity, large sized bore piston is used. A defective piston will not be able to lift as much as possible. Even though the cylinder may not be leaking outside, a damaged piston will allow oil to pass the piston. So the pressure will not reach your required level and will not do lifting as expected.

Rod: the rod is the part that connects the gland and the piston of the cylinder. The diameter and hardness of the rod are very important for the cylinders. For heavy duty cylinders, the rod is stronger which is less likely to bend.

Gland: the gland travels through the piston inside the cylinder. It is an essential part of the cylinder as it removes the debris from the rod.

End cap: it is the base of cylinder. The end cap is also important as it does not allow any foreign particles to enter in the tube.

The operational principle and kinds of hydraulic cylinders

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Hydraulic motors or hydraulic Cylinders are a form of mechanical actuators that are functioned by some energy source. The hydraulic cylinder is used to produce a unidirectional force from a unidirectional stroke. These cylinders are used for an extensive range of applications, mainly in engineering vehicles.

Hydraulic cylinders function by gaining power from some type of pressurized hydraulic fluid. This hydraulic fluid is oil in maximum cases. The cylinder consist of a barrel that is attached to a piston. The piston has a piston rod that permits a user to move it front and back. Whereas the key function of the piston is to isolated pressure zones in the barrel, the function of the piston rod is to connect the hydraulic motor with the machine part that carries out the work.

There are various types of hydraulic cylinders accessible in the market. Based on their design, hydraulic cylinders are considered into tie rod cylinder and welded body cylinders. Welded body cylinders are more habitually used than the tie rod cylinders as they incline to have numerous advantages. They not simply fit better in any kind of machinery, but also simply lend to diverse customizations. Hydraulic equipment such as lift-gates, bulldozers, oil rigs, forklift trucks, cranes, etc. all include the use of welded body cylinders.

Various kinds of special hydraulic cylinders are used for industrial purposes. These consist of differential cylinders, plunger cylinder, and telescopic cylinders. Some of them have been discussed below in brief:

Differential cylinders

These cylinders function like ordinary cylinders whereas pulling. Whereas they can be prepared like normal cylinders, a special control requires to be attached to them.

Plunger cylinders

Plunger cylinders are types of hydraulic cylinders that originate devoid of a piston. There can also be models that contain the piston but lack the seals. This kind of cylinders can be used only as pushing cylinders. These models generally have a very thick piston rod.

Telescopic cylinders

Telescopic cylinders use the piston barrel as a piston rod and another piston rod is working to act as the main piston rod. This is so done because sometimes the length of this hydraulic cylinder that comprises the stroke, the piston thickness, the bottom thickness and the head and length of the connections doesn’t fit in the total machine. Telescopic cylinders are more expensive than normal cylinders. Single acting telescopic cylinders are simply obtainable in the market. Though, the double acting telescopic cylinders need to be manufactured especially.

The Use and Functioning of Hydraulic Cylinders


A Hydraulic cylinder or Hydraulic Motor is a mechanical apparatus for substituting power by the use of high force oil acting in contrast to the surface region of a cylinder inside the chamber. A pressure driven barrel provides direct force in one hub in either one or two bearings. Hydraulic cylinders come in various types and their uses differ depending on their strategy.

In a path of the mill, pressure driven barrel with a cylinder oil is stimulated in at either end by means of specific sort of “port” and the cylinder is fixed to the tube by a double acting seal and in addition between the pole and the organ by a solitary performing seal. What’s more, you will for the greatest part discover a wiper seal is used as a part of the organ to have soil out. This Hydraulic cylinder design is observed as a double acting chamber. It is the force subsequent up on the cylinder surface, which makes Hydraulic cylinders, produce a straight extension. In light of the fact that the pole is attached to the cylinder, it moves also. Delivery of water driven force over the port to one side of the cylinder makes it transport in one manner, and demand of force through the port to the opposite side of the cylinder will make it move in the opposite course.

In a Single performing cylinder, oil just follows up on one side of the cylinder so it can just be automatically moved in one heading. An outside force, gravity, or some of the time a spring or an alternative water driven chamber gives drive in the opposite heading. Single acting cylinders can moreover be of the “dislodging” sort where the oil force acts directly on the surface of the pole, and there is no cylinder. In this chamber idea, the surface range of the bar limits the energy, though in a barrel with a cylinder, the pole may be of any size and the influence could be determined or controlled by the cylinder plan.

The Hydraulic hand pump is an apparatus that assistances us in moving liquids starting with some area then onto the next. A pump that is not equipped with any water driven or electric apparatus is a direct hand pump. High force pumps eliminate liquids from under the ground earlier than the hand pump and are in this way favoured over water powered ones for general requisitions.