Complete Hydraulic Bucket Cylinder Seal Kit for Caterpillar 320D Excavator - Replaces 233-2618 - Rod & Piston Seal Set

Stop the Leak — Complete Bucket Cylinder Seal Kit

Your bucket cylinder is leaking. Hydraulic oil is running down the cylinder rod, pooling on the boom, and dripping onto the ground. Every drop is money — and every hour you run it, the cylinder bore is getting contaminated with dirt that's destroying the internal finish.

Fix it now before a $200 seal job becomes a $3,000 cylinder rebuild.

The Problem

Hydraulic cylinder seals wear out from three things:

• Age: The rubber and urethane compounds harden and crack over time
• Heat: Repeated thermal cycling degrades the seal material
• Contamination: Dirt past the wiper seal scores the rod, which cuts the main seal

Once the rod seal starts leaking, dirt enters the cylinder bore. This scores the bore surface and damages the piston seal too. The longer you wait, the more expensive the repair becomes.

What's Included — Complete Kit

• Rod Seal: High-performance urethane — outlasts standard nitrile seals by 2–3x
• Wiper / Dust Seal: Keeps dirt and debris out of the cylinder
• Piston Seal: Maintains pressure on both sides of the piston
• Wear Rings / Guide Bands: Keep the piston centered in the bore, preventing metal-to-metal contact
• O-Rings: All static O-rings for head gland, piston, and end cap
• Backup Rings: Anti-extrusion rings where required

Everything you need in one bag. No chasing individual seals from multiple suppliers.

Technical Specifications

• Cat Part Number: 233-2618
• Application: Bucket Cylinder
• Rod Seal Material: High-performance urethane
• O-Ring Material: Nitrile (Buna-N) — compatible with petroleum-based hydraulic fluids
• Condition: Brand New, Complete Kit

Compatible Caterpillar Equipment

• Cat 320D / 320D L Excavator — Bucket Cylinder
• Cat 320D LRR Excavator — Bucket Cylinder
• Cat 320D2 Excavator — Bucket Cylinder

This kit is specifically for the BUCKET cylinder on Cat 320D excavators. If you need the STICK (arm) cylinder kit or BOOM cylinder kit, search by your Cat part number — we carry those too.

Why Buy From Trenchwell?

• Save 45%+ vs Dealer: Cat dealers charge $220–$280 for this seal kit. We sell the complete kit for $139.
• Premium Seal Materials: Uses high-performance urethane rod seals — the same class of material found in premium hydraulic seal brands. These outlast standard nitrile seals by 2–3x in high-heat applications.
• Complete Kit: Every seal, O-ring, wear ring, and backup ring you need. One bag, one part number, one order. No searching for individual seals.
• Free Shipping: Seal kits are lightweight — we ship them free.
• Protect Your Cylinder: A $139 seal kit prevents a $3,000+ cylinder rebuild. Don't wait.

Installation Notes

Tip: Before disassembly, clean the outside of the cylinder thoroughly to prevent contamination. Inspect the rod surface for scoring — if the rod is scored, it will cut through new seals quickly. Light scoring can be buffed with 600-grit emery cloth, but deep grooves require rod repair or replacement.