Hydraulic seal is a drive system that uses oil fluid as its driving force. Regarding the form of hydraulic seals, usually for each manufacture gives different types this is important to know as a way to choose hydraulic seals while the material used refers to the load and application temperature For standard, often used poly Urethane (PU), Nitrile Rubber (NBR), Hydrogenated Rubber (NHBR), Ethylene Propylene Rubber (EPDM), Fluorine Rubber (FR) and many more special or combined materials used. Hydraulic seal serves to prevent leakage from a system that moves reciprocally (up / down, left / right).

Advantages of hydraulic systems:

· Has a large mechanical power

· Hydraulic cylinders are more durable when compared to pneumatic cylinders (air cylinders).

· Oil as a driving force will not be used up / reduced if there is no leakage. So that only an initial investment is needed.

Weaknesses in hydraulic systems:

· Not environmentally friendly (if there is a leak in the piping system).

· Oil prices are quite expensive.

· Less responsive when compared with pneumatics.