Product Name: Rebuild Kit, Piston Rings (Hi‑Load Piston) – Part No. 20458821

Description:
This component is a specialized rebuild kit for the Hi‑Load hydraulic piston used in waterjet intensifier pumps. It contains the high‑performance sealing components necessary to restore the integrity of the hydraulic piston, which converts hydraulic pressure into the linear force that drives the high‑pressure plunger.

The kit is specifically designed for the Hi‑Load piston design, which uses advanced materials and an extra support sleeve for extended service life. Unlike the High Pressure Seal Kit used for the water side of the pump, this kit is dedicated to the low‑pressure hydraulic (oil) side.

The kit includes a multi‑component sealing stack for the centre groove of the piston, which consists of two Nylon Backup Rings, an inner Energizer Ring, and an outer Teflon Cap Ring. These engineered components provide a leak‑tight dynamic seal against the hydraulic cylinder bore, preventing oil bypass and ensuring consistent force delivery.

Applications:

• Rebuilding the Hi‑Load hydraulic piston in the low‑pressure (hydraulic) section of waterjet intensifier pumps

• Restoring piston sealing integrity when symptoms of hydraulic bypass (erratic cycling, inability to maintain pressure) appear

• Used during scheduled major maintenance, minor maintenance, or complete pump overhaul procedures

• Compatible with 60,000–94,000 PSI (approximately 4,137–6,480 bar) waterjet intensifier systems

Features:

• Hi‑Load Piston Compatibility: Engineered specifically for the upgraded Hi‑Load piston design, which incorporates an extra support sleeve for longer life

• Teflon Cap Ring with Energiser: The centre seal consists of an inner energiser (elastomeric) ring and an outer Teflon cap ring, providing low friction and high wear resistance

• Nylon Backup Rings: Includes rigid Nylon backup rings to prevent the softer Teflon cap and energiser from extruding under extreme pressure

• Critical Consumable Component: Designed for periodic replacement; a worn centre band allows oil to bypass the piston, reducing pressure and causing erratic operation

• Complete Kit: Contains all necessary rings (Nylon Backup Rings, Energiser Ring, Teflon Cap Ring) for a full piston rebuild

Maintenance:

When to Replace (Failure Diagnosis):

• Erratic Intensifier Cycling: The pump may cycle irregularly, overstroke, or “knock” due to hydraulic oil bypassing the worn piston seals

• Inability to Build Full Pressure: Worn piston rings allow internal leakage, preventing the system from reaching its rated cutting pressure

• Worn Cylinder Bore: Excessive grooving or wear on the hydraulic cylinder bore is indicative of piston seal wear, requiring inspection of the piston assembly

• Scheduled Overhaul: Standard practice to replace the piston rings during major intensifier overhauls or when the pump is disassembled for seal replacement

Inspection and Replacement Guidelines:

• Full Depressurisation (Critical): Before any maintenance, fully depressurise both the hydraulic system and the high‑pressure water circuit, and follow lockout/tagout procedures

• Special Tool Required (Ring Compressor): After installing the Teflon Cap Ring, it must be resized using a ring compressor for at least three minutes so that it will fit properly into the hydraulic cylinder bore

• Heating the Teflon Cap Ring (Installation Aid): To facilitate installation, heat the Teflon Cap Ring in 150–200°F (65–90°C) water for 2–3 minutes to soften it

• Proper Orientation: The two Nylon Backup Rings must be installed on each side of the Teflon Cap, with the curved inside edges facing the Teflon Cap. The outer Teflon Bearing Rings should be rotated so the end joints do not line up

• Lubrication: Generously lubricate the new seals, the piston assembly, and the hydraulic cylinder bore with clean hydraulic oil during reassembly to prevent dry start‑up

• Avoid Scratching: Use non‑metallic tools to remove old seals and avoid scratching the piston or the cylinder bore, as scratches will create leak paths and damage new seals

• Installation Force: Some pressure may be required to push the piston assembly into the cylinder bore. Ensure the ring compressor is in place to contain the wear bearings and seal assembly

• Clean Area Maintenance: Perform the rebuild in a designated clean area to prevent contamination