CAT 552-4638 Sleeve Bearing

CAT 552-4638 is a heavy-duty straight-tube sleeve bearing (steel-based bronze alloy) designed by Caterpillar specifically for boom, stick, and bucket pin joints. It is suitable for medium-to-high pressure, oscillating/low-speed rotational conditions, and features impact resistance, wear resistance, and self-lubrication. The following are the core information:

Core Parameters
Item Details
Basic Attributes
Model 552-4638, straight-tube sleeve bearing (without oil groove, suitable for pin clearance fit), primarily bears radial loads, can withstand small bidirectional oscillating loads, suitable for boom, stick, and bucket pin joints, linear velocity ≤0.5m/s
Compatible Models
CAT 320, 323, 336 excavators, 950, 966 loaders, suitable for boom-stick and stick-bucket pin joints of E320D2, E336F, etc., 2 of these bearings are required for each joint.

Material and Manufacturing Process
Base material is 42CrMo alloy steel (HRC) 45-50), inner surface sintered CuSn10Pb10 bronze alloy layer (2-3mm thick), surface plated with lead-tin alloy (0.05mm), operating temperature -20℃ to +100℃, grease lubrication recommended (NLGI 2 lithium-based grease)

Key Dimensions: Outer diameter 76.20mm (3.0in), inner diameter 63.50mm (2.5in), length 50.80mm (2.0in), wall thickness 6.35mm, weight approx. 0.58kg, compatible pin diameter 63.50mm, mounting clearance 0.08-0.12mm

Functional Parameters: Radial rated load 180kN, limiting speed 50rpm (oscillating condition), mounting method is clearance fit (shaft tolerance h8, hole tolerance H7), compatible pin surface roughness Ra≤1.6μm

Matching Components: Compatible pin 552-4639, dust seal 552-4640 requires cold pressing into the bearing housing (pressing force ≤ 15kN). It is recommended to replenish grease every 200 hours.

Alternative Model: Can replace older sleeve bearings such as 154-7322 and 207-6895.

Installation and Maintenance Points:
Preparation before installation: Clean the bearing housing bore and pin surface, removing burrs, oil, and metal debris; check the bearing inner bore for scoring and alloy layer peeling; measure the housing bore diameter and pin diameter to ensure the fit clearance meets requirements; the pin surface must be hardened (HRC≥50) and the roughness must meet requirements.

Installation Steps: Apply anaerobic adhesive (such as Loctite 609) to the outer diameter of the bearing. Use a special press to smoothly press it into the bearing housing (pressing force ≤ 15kN). Do not strike the bearing end face. Install the pin, ensuring the bearing and pin coaxiality is ≤ 0.10mm. Install the dust seal and tighten the pin fixing bolts to the specified torque (e.g., M24×2, torque 280-320N・m).

Maintenance and Replacement: Check the bearing’s operating condition every 200 hours, listening for abnormal noises and measuring the temperature. Replenish with grease every 500 hours (use 1/2 of the bearing clearance volume). Replace the bearing immediately when the inner diameter wear exceeds 0.2mm, the alloy layer peels off, or cracks appear.