KIT 1842 Ceramic Coated Piston Set

Precision 18mm | High-Thermal Resistance | Heavy-Duty Core

This kit is designed to restore the smooth reciprocating action of your pump’s plungers. The 18mm diameter is a standard size for many mid-to-large frame pumps, and the ceramic coating ensures that the high-pressure water seals (packings) glide over the surface with minimal friction and heat buildup.

Technical Specifications

• Piston Diameter: 18mm

• Type: Ceramic Coated (Stainless Steel core with a bonded ceramic outer layer)

• Compatibility: Fits several AR pump series including the RK, RKA, RKV, and XW families (Verify your specific pump model).

• Kit Contents: Usually sold as a set of 3 pistons (one complete head overhaul).

Key Features

• Reduced Friction: The mirror-polished ceramic surface significantly reduces the “drag” on the high-pressure seals, preventing the seals from overheating and melting during long bypass cycles.

• Corrosion Resistance: The ceramic layer is chemically inert, protecting the underlying metal from aggressive detergents, hard water minerals, and salt-based cleaning solutions.

• Impact Durability: Because these have a metal core, they are less likely to shatter if the pump experiences a severe mechanical “knock” or if the pump is dropped, compared to 100% solid ceramic pistons.

• Thermal Barrier: Ceramic acts as an insulator, keeping the heat of the pressurized water from transferring into the oil crankcase.

When to Replace Your Pistons

• Visible Scoring: If you see vertical scratches or “grooves” on the piston surface.

• Water in Oil: If your pump oil looks milky, it often means the piston surface is worn, allowing water to bypass the seals into the crankcase.

• Constant Seal Failure: If you find yourself replacing water seals every few weeks, the rough surface of an old piston is likely “shaving” the new seals down.

Technical Summary