CATEngine Parts

392-4576-392-4577 Boom Cylinder Seal Kit — Cat 307D 307E

This is a Boom Cylinder Seal Kit designed for CAT excavators, containing all necessary seals to rebuild the hydraulic boom cylinder. Its function is to maintain hydraulic pressure within the cylinder, ensuring smooth and controlled operation of the boom. A leaking or damaged seal kit will result in slow or jerky boom movement, or the inability to hold position under load.

Boom Cylinder Seal Kit – Part No 392-4576-392-4577 – CAT Spare Part
Part Specifications
BrandCAT
CategoryEngine Parts
ConditionAftermarket — OEM Specification
DispatchSame-day from Mumbai (before 3 PM IST)
GST InvoiceAvailable — all orders
Export DocsCommercial invoice, packing list, COO

Compatible Models

Always verify with serial number before ordering.

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Installation & Application Notes

Inspect mating surfaces for wear before fitting. Use torque specs from service manual. Replace gaskets and seals as a set — reusing compressed gaskets causes oil leaks. Clean all oil passages with compressed air.

Always consult the OEM service manual for model-specific torque values and procedures. WhatsApp our technical team if you need fitment guidance.

Part TypeHydraulic Seal Kit
MaterialNBR Rubber, PTFE
ApplicationBoom hydraulic cylinder
Service LifeReplace as needed based on inspection
CompatibilityOEM specification
ConditionNew — OEM specification aftermarket

Failure Symptoms

The first sign of a failing boom cylinder seal kit is often slow or weak hydraulic response in the boom, or a noticeable drift when the boom is held in position. If ignored, the cylinder may lose significant lifting capacity, and external leaks can lead to hydraulic system contamination and fluid loss. This can compromise the machine's ability to perform its work safely and efficiently.

Installation Tip

Thoroughly clean all internal surfaces of the cylinder bore and piston before installing the new seals to prevent damage. Ensure all seals are properly seated and lubricated to avoid tearing during installation.

Service Note

When replacing boom cylinder seals, inspect the cylinder rod for pitting or scoring, and check the hydraulic fluid for contamination.