Piston seal kits contain accessories used for the sealing and replacement of piston seals, which make the areas between the cylinder bores and the pistons airtight and watertight. The kits include products like O-rings, lubricant, washers and sealing guide tools.What are piston seal kits used for? Pistons are found in engines, hydraulic equipment, pneumatic actuators, pumps and air compressors. They prevent pressure losses in these devices that may cause damage to equipment or place operators at risk.Differential pressures acting on the piston to extend or retract the piston rod can wear out the sealant materials over time. Damage can also be caused to piston seals by oil leakages or foreign matter in the lubricant fluids. Piston seal kits are used to replace or repair the worn seals around the bearings and seatings. Types of piston seal kits Piston seal kits are broadly divided into two varieties: Single-acting kits are used for seals that absorb one-sided pressures from the pistons. Double-acting kits designed for use with sealing parts taking pressure from both sides of the pistons.