CAT 136-9521 BUSHING

CAT 136-9521 is a Caterpillar genuine straight-sleeve heavy-duty steel bushing, suitable for the hinge points of medium and large excavators and loaders. It is used for pin connections of the boom, stick, or bucket, and withstands radial loads and low-speed oscillation conditions. The following are the core information:

Core Technical Parameters
Item Details
Part Model: CAT 136-9521 (1369521) Straight-sleeve heavy-duty steel bushing (suitable for hinge points of medium and large excavators, connecting boom/stick/bucket, withstands radial loads + low-speed oscillation)

Core Material: 20CrMnTi carburized steel, surface carburized and quenched, hardness HRC 58–62, carburized layer depth 1.2–1.5 mm, 3 axial lubrication grooves in the inner hole, compatible with Caterpillar-specific lithium-based grease (NLGI 2)

Key Dimensions: Inner diameter 90 mm, outer diameter 110 mm, length 80 mm, wall thickness 10 mm mm, inner hole roundness tolerance ≤0.01 mm, mounting surface perpendicularity tolerance ≤0.02 mm
Single weight: Approx. 3.15 kg (6.94 lb)
Compatible models: CAT 349D2/349F excavators (boom/stick pins), 986M/988K loaders (bucket hinge), compatible pin model 136-9522, often used with 136-9523 sealing rings
Operating compatibility: Rated radial load 180 kN, limiting speed 800 rpm, operating temperature -40℃ to +140℃, suitable for low-speed heavy-load swinging conditions
Core functions and structural features: Heavy-duty wear-resistant: Carburized steel surface hardening treatment, suitable for heavy-load swinging forces of the boom/stick pins, impact load resistance up to 220 kN, service life over 7000 hours.

Lubrication Optimization: Three axial lubrication grooves in the inner bore ensure uniform grease distribution, reducing the coefficient of friction (f≤0.08) and minimizing adhesive wear between the pin and bushing.

Precise Fit: A clearance of 0.02–0.03 mm with the 136-9522 pin ensures smooth, unobstructed movement.

Deformation Resistance Enhancement: Integral forging and precision grinding ensures uniform wall thickness (tolerance ±0.01 mm), reducing deformation under heavy loads.

Installation and Maintenance Points:
Installation Specifications: Clean the mounting hole, ensuring it is free of rust, oil, and burrs. The hole tolerance is +0.01–+0.02 mm. Use cold pressing with a pressing force of 18–20 kN. Do not strike the end face.

After installation, check the inner bore roundness to ensure it is ≤0.01 mm and the clearance with the 136-9522 pin is 0.02–0.03 mm.

Secure with M16×1.5 bolts (8.8 grade) to a torque of 95–100 N·m to prevent axial movement of the bushing.

Maintenance Recommendations: Inspect the bushing every 800 working hours for wear, cracks, and grease leaks. Replace as per standard.

Lubricate with Caterpillar-specific lithium-based grease, adding 40–50 g each time, ensuring the lubrication grooves are full.

Replace the 136-9522 pin and 136-9523 seal simultaneously during replacement to ensure compatibility and service life.