CAT 329-1381 Straight Sleeve Bearing

CAT 329-1381 is a Caterpillar genuine heavy-duty linear sleeve bushing, suitable for use in the hinged parts of construction machinery (such as boom, stick, and bucket pins) to support the pins and reduce wear from relative motion. The following are precise original factory specifications and application information, excluding replacement parts (Cat®)…

Core Technical Parameters

Item Details
Part Model: CAT 329-1381 (Straight Sleeve Bushing, Steel-Backed Bronze Composite Structure)

Material: Steel back + bronze alloy layer + molybdenum disulfide (MoS₂) solid lubricant coating. The steel back is 42CrMo alloy steel, and the bronze layer is CuSn10Pb10. Coating thickness: 0.02-0.05 mm.

Key Dimensions: Inner diameter 63.50 mm (2.5 in), outer diameter 76.20 mm (3.0 in), total length 82.55 mm (3.25 in), steel back thickness 2.0 mm, bronze layer thickness 1.5 mm, lubrication groove depth 0.5 mm.

Performance Parameters: Operating temperature -40℃ to +120℃, load capacity ≥ 200 MPa, coefficient of friction ≤ 0.08 (oil-free initial state), wear life ≥ 8000 hours (heavy load conditions).

Single Weight: Approx. 0.56 kg (1.23 lbs)

Tolerances: Inner diameter tolerance H7 (+0.030/0 mm), outer diameter tolerance f7 (0/-0.030 mm), length tolerance ±0.1 mm, coating thickness tolerance ±0.01 mm

Core Features: The steel backing provides structural strength, while the bronze layer and MoS₂ coating reduce friction, making it suitable for heavy-duty, low-speed oscillating conditions, reducing wear on pins and bushings, and extending component life.

Structure and Core Features:

Composite Layer Structure: The outer 42CrMo steel backing ensures compressive strength, the middle CuSn10Pb10 bronze layer provides a load-bearing and lubrication base, and the inner MoS₂ coating enables solid lubrication, suitable for oil-free or boundary lubrication conditions, reducing the coefficient of friction (Cat®…).

Lubrication Groove Design: Axial lubrication grooves are distributed in the inner bore, working with a grease lubrication system to store grease, forming a stable oil film between the pin and bushing, reducing dry friction and improving wear resistance.

High-precision tolerance control: The inner and outer diameter tolerances are strictly matched between the pin and the mounting hole to ensure no loosening after installation, avoid abnormal wear under impact loads, and meet the positioning requirements of heavy-duty articulated parts.

Corrosion protection: The steel back surface is galvanized and passivated, achieving an IP65 rust prevention rating, suitable for harsh working conditions of construction machinery such as dusty, humid, and saline environments.

Compatible models and application scenarios:

Compatible equipment: CAT 320, 323, and 329 series excavators, 950 and 966 series loaders, and some bulldozer and grader working devices, such as the boom and stick articulation, stick and bucket connection pins, and cylinder lugs.

Core application: Installed between the pin and the mounting hole, it supports the pin and reduces friction and wear during relative movement, absorbs impact loads, ensures flexible operation of the working device, and is suitable for heavy-duty operations such as earthmoving and material loading.