CAT 081-9221 RETAINER

CAT 081-9221 (0819221) is a Caterpillar genuine hydraulic cylinder piston retainer for construction machinery. It is compatible with the 308E2 excavator and 242D/246D skid steer loaders. It is used to secure the cylinder piston and piston rod, preventing the piston from loosening or shifting during reciprocating motion, ensuring the coaxiality of the piston and seals, and is suitable for high-pressure and vibration conditions. It prevents seal damage and hydraulic oil leakage due to retention failure.

Core Parameters and Information

Project Details
Part Model: CAT 081-9221 (0819221) Piston Holder

Type: Hydraulic cylinder piston holder, round nut + locking washer combination structure

Material: Round nut 40Cr alloy steel, blackened surface treatment; Locking washer 65Mn spring steel, galvanized and passivated surface

Key Dimensions: Adapted piston rod thread M45×2, outer diameter 60mm, thickness 12mm; Locking washer inner diameter 45mm, outer diameter 58mm

Performance Parameters: Operating temperature -40℃ to +120℃, tightening torque 180N・m, anti-loosening torque ≥150N・m, tensile strength ≥1000MPa

Compatible Models: CAT 308E2 excavator, 242D/246D skid steer loader

Matching Relationships Used in conjunction with pistons, piston rods, and main seals, this device is installed at the rear end of the piston to fix its position.

Compatibility and Applications
Suitable Parts: The connection between the piston and piston rod in the boom, stick, and bucket cylinders of CAT 308E2 excavators and 242D/246D skid steer loaders, preventing piston loosening and displacement, and ensuring the coaxiality of the seals.

Application Scenarios: Suitable for high-pressure and vibration conditions, such as the high-pressure reciprocating motion of the cylinders during excavation operations in excavators. The retainer prevents piston loosening, which could lead to seal damage and leakage, ensuring the stability of the hydraulic system.

Usage: Used with pistons, piston rods, and main seals. After installation, a locking washer is used to prevent loosening, ensuring a secure connection between the piston and piston rod without relative displacement.

Installation and Maintenance Points
Installation: Clean the piston rod threads and piston inner bore, and apply thread-locking adhesive; tighten the retainer to the rear end of the piston using a torque wrench to 180 N·m; install the locking washer, ensuring the washer claws align with the retainer groove and piston end face to prevent loosening.

Maintenance: Check the tightening of the retainer every 500 hours. Ensure the locking washers are not deformed or broken. If loosening is found, retighten to the specified torque and replace any damaged locking washers.

Replacement: When disassembling the old retainer, check for thread damage. If the threads are stripped, replace the piston rod. Before installing the new retainer, check the dimensions and thread accuracy to ensure it matches the piston rod and that the locking washers are in good elasticity.