CAT 391-9811 Bearing-Slv-Gd

CAT 391-9811 is a Caterpillar standard load type straight steel sleeve bearing (bushing), suitable for medium load swing joints of Cat 950GC loader boom/rocker arm, 320D excavator stick, 140M grader blade, etc., used to reduce friction and buffer impact. The following are the core technology and application information:

Core Technical Parameters
Item Details
Basic Attributes
Model 391-9811, type is standard load straight sleeve bearing, suitable for Cat 950GC loader boom/rocker arm hinges, 320D excavator stick pins, 140M grader blade pivots, material is low carbon alloy steel (surface hardened HRC 52-58), operating temperature -40℃ to +120℃, single weight approximately 0.58 kg (1.28 lb), suitable for grease lubrication, rated radial dynamic load ≥28 kN, radial static load ≥70 kN, wear life ≥2500 hours, no internal or external lubrication grooves or cross holes

Key Dimensions: Inner diameter 95.25 mm (3.75 in, tolerance H7, +0.040/0 mm), outer diameter 105.00 mm (4.134 in, tolerance g6, -0.015/-0.035 mm), total length 42.86 mm (1.687 in, tolerance ±0.15 mm), wall thickness 4.875 mm, chamfer at both ends r=1 mm, inner hole roughness Ra≤1.6 μm, no flange, suitable for oil-grooved pins, mounting hole surface roughness Ra≤1.6 μm

Material and Process: Low carbon alloy steel forged blank, spheroidizing annealing → rough turning → finish turning → quenching (860℃ oil quenching) → tempering (180℃) → fine grinding → deburring → rust prevention treatment, surface hardened layer depth 0.8-1.2 mm diameter, impact and vibration resistant, suitable for low to medium speed (≤2.5 m/s), medium load swing/rotation conditions.
Compatible with Cat 950GC/966K loader working device hinge points, 320D/323D excavator stick/boom pins, 140M/160M grader blade connecting pins, and 420D skid steer loader connecting rod hinge parts. Used to withstand radial medium loads and buffer vibration and impact.
Assembly fit: Compatible with 95.25 mm diameter pins (tolerance f7, -0.030/-0.060 mm), 105.00 mm diameter mounting holes (tolerance H7, +0.040/0 mm), interference fit 0.015-0.035 mm. mm, press-fit installation, welding or heating deformation is prohibited.

Installation and Maintenance Points:

Before installation, clean the pin and mounting hole. Check the bearing inner hole for scratches and bulges. Measure the inner diameter of the mounting hole and the outer diameter of the bearing to ensure an interference fit of 0.015-0.035 mm. The surface roughness of the hole Ra ≤ 1.6 μm.

Use a hydraulic press to press vertically, with a pressing force ≤ 80 kN. Ensure the bearing end face fits snugly against the mounting hole step without misalignment. After press-fitting, the roundness of the inner hole should be ≤ 0.02 mm. Do not directly strike the bearing outer ring with a hammer.

Maintenance Recommendations: Check the bearing clearance every 1200 hours. Replace immediately if the radial clearance > 0.3 mm or if abnormal noise or overheating occurs. Lubricate daily with NLGI 2 lithium-based grease, replenishing grease every 250 hours, adding only enough to overflow a small amount of new grease each time.