Cylinder seal – can you replace it by yourself?

Hydraulic Cylinder Seal

Hydraulic cylinders are used in various hydraulic systems of construction vehicles and smaller machines. They exchange energy under the influence of the pressure created by the liquid (most often it is concentrated oil). Thanks to this they set individual elements in motion, for example an excavator arm. The hydraulic cylinder working body can be a piston, a plunger or a diaphragm, housed in a cylindrical body.

Hydraulic cylinders could not work properly without seal kits. During work, they are subjected to high pressures, temperatures and forces. In such difficult conditions they must stop leaks of the hydraulic fluid both inside and outside. Therefore, we must ensure the highest quality of seals and constantly monitor their condition.

Hydraulic cylinder damage

The hydraulic cylinder is much less complicated in construction than the hydraulic distributor. However, whether we are able to repair the first one ourselves depends on the type and degree of failure. A frequent cause of damage to a hydraulic cylinder is the work out of its seals. There are three types of seal kits in the excavator or mini excavator arm. These are: boom cylinder seal, bucket cylinder seal and arm cylinder seal. Incorrect choice of seals or their questionable quality significantly shortens their operational capabilities. Leaks will cause sediments and impurities on the actuator’s mechanical system, as well as a decrease in the efficiency and power of the entire system.

If you are sure that only the seal needs repair, you can try to replace it yourself. Although replacing the seal does not seem too complicated, it requires some precision, knowledge and of course workshop facilities. Therefore, if you do not feel confident, you should seek help from a specialist. Inaccurate installation can cause further unwanted damage.

Replacement of hydraulic cylinder seal

The first step is to disassemble the actuator and check its technical condition. Wait for the piston rod to be pulled out until the residual oil has drained out. If the actuator is not significantly damaged, it should not fall out (except for the guides). Estimate the condition of the piston rod, piston and cylindrical pipe. If nothing raises objections, you can start replacing the seals. To do this, disconnect the piston from the piston rod, then slide the stuffing box out of it. Replace the packing on the gland first, then the piston seals. After all, you can do the re-assembly. The gland must be on the piston rod – same as when dismantling. Then slide the piston in and take care that the guides and seals do not slide off it.