Hydraulic cylinders are tools used on many machines and multiple sectors of activity: excavators, press, industrial solutions, agricultural machinery, jacks, etc. Exposed to high pressures and used in sometimes demanding environments, hydraulic cylinders are not suitable for safe from breakdowns. Discover the main malfunctions encountered by these tools and the solutions to prevent or repair them.
Definition and operation of a hydraulic cylinder
To fully understand where failures in a hydraulic cylinder can come from, it is necessary to have a clear idea of how such tools work.
A hydraulic cylinder is made up of several parts: a cylinder in which a piston pushed by a rod moves. This is driven by a pressurized liquid which moves it in the tube and which can exert its force in one or two directions (single or double acting). The ends are closed by gaskets.
The main failures of a hydraulic cylinder
We asked the repair service of SAH Leduc, a hydraulic cylinder specialist, for the main failures that led to a cylinder being returned to the workshop.
Fluid leakage problems
The first is the liquid leak. The force produced by a hydraulic cylinder originates from the pressure existing in mineral oil, the liquid which pushes the rod.
At the slightest imperfection on a part of the cylinder, this liquid can leak, causing a net loss of power. Leakage is therefore the main cause of failure since many factors can cause it.
The external leak is the easiest to detect. It occurs when the liquid comes out of the cylinder. This is usually caused by a problem with the defective seal. The solution is then simply to change it. It is also recommended to replace them regularly to avoid the appearance of these failures, easily avoidable.
More complicated to identify, the internal leak occurs when the liquid leaks but remains inside the tube (it then fills the “empty” part of the cylinder. There is a loss of power but without the possibility of observing the source of a possible leak, making diagnosis more difficult It is then necessary to disassemble the cylinder.
In the event of an external leak, the cause can also be linked to the wear of a seal on the piston but also to the appearance of micro-scratches, affecting the good sealing of the assembly. In this case, it is necessary to chrome the inside of the cylinder to smooth it out again.
Other breakdowns on hydraulic cylinder
The other failures are mainly mechanical causes. A jack is sometimes used in engaging situations such as on a construction site for example. It may happen that it receives debris, causing a shock. This can impact the seal but also quite simply hinder the stroke of the piston in the cylinder.
Likewise, sometimes, by forcing on the rod, it can be twisted. It is then necessary to straighten it.
Finally, the cylinder can also simply be subjected to the effects of time. A bit like the wear of the seals, other parts can deteriorate over time such as hydraulic hoses for example. It is then necessary to replace them to restore the initial performance and correct operation of the hydraulic cylinder.