247-8868 Boom Cylinder Seal Kit for Caterpillar 320D

The 247-8868 Boom Cylinder Seal Kit is an aftermarket replacement hydraulic sealing kit for selected Caterpillar excavator boom cylinders. It is primarily associated with Cat 320D series excavators and the 242-6731 boom cylinder and seal group.

This seal kit is intended for boom hydraulic cylinder repair and resealing. The referenced cylinder has an 85 mm piston rod and a 120 mm cylinder bore. Because different cylinder configurations may be used within the same machine series, the cylinder group number and machine serial number should be checked before ordering.

Compatible Caterpillar Excavator Applications

Caterpillar parts references list 247-8868 for selected hydraulic boom cylinder configurations used on the following excavators:

• Cat 320D / 320D L / 320D LN

• Cat 320D GC

• Cat 320D FM / 320D RR / 320D LRR

• Cat 319D L / 319D LN

• Cat 321D LCR

• Selected Cat 323D L / 323D LN applications

These are catalog model references, not a guarantee of fitment for every machine configuration. The original cylinder group, machine serial number and seal specifications should be confirmed before purchase.

247-8868 Original Cat Seal Kit Components

The Caterpillar original parts listing for 247-8868 provides the following sealing component references. This table is intended to help buyers identify the required seal kit and compare the original specification with an aftermarket replacement.

The table above represents the original Cat kit reference, not a confirmed packing list for every aftermarket kit. The actual supplied components, quantities and materials should be checked before shipment.

247-8868 and Related Cat Seal Kit References

The reference 2478868 is the non-hyphenated version of Cat part number 247-8868. It does not represent a separate OEM part number.

Cat also lists 350-0962 as a hydraulic cylinder seal kit for related excavator applications. However, the original kit component references are not identical, and compatibility should not be assumed without checking the cylinder group and service parts information.

For accurate replacement selection, identify the original 247-8868 seal kit specification rather than relying only on the excavator model.

Boom Cylinder Inspection and Seal Replacement

Boom cylinder seals should be inspected when hydraulic oil leakage, abnormal cylinder drift or reduced sealing performance is observed. These symptoms can also have causes outside the cylinder sealing system.

During cylinder repair, inspect:

• Piston rod surface for scoring, corrosion and wear.

• Cylinder barrel surface and sealing grooves.

• Rod seals, piston seals and wear ring locations.

• Cylinder head, piston and associated guide components.

• Hydraulic oil cleanliness and possible contamination.

• Seal installation direction and correct component positioning.

Hydraulic pressure must be safely released before disassembly. Installation and repair procedures should follow the appropriate Caterpillar service information.