Description
CAT 7T-2879 Bulldozer Trunnion
| CAT 7T-2879 Bulldozer Trunnion |
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The CAT 7T-2879 is a heavy-duty integral trunnion assembly for Caterpillar bulldozer/loader buckets/booms. It is compatible with the bucket hinge points of D6T/D6R/D7R and 966H/972H loaders. Its core function is to provide radial support and axial positioning for bucket/boom swing, withstand combined loads, and ensure operational stability. The following is professional structured information.
Core Parameters (Professional Version)
Project Details
Basic Attributes
Model 7T-2879, Quantity per unit: 2 pieces (symmetrically arranged on both sides of the hinge point), Fitting pin diameter: 85 mm, Matching bushing: 7T-2880, Locking nut: 8T-4121, Single component weight: 12.3 kg, including trunnion body, wear-resistant bushing, dust seal, positioning flange, and lubrication nozzle
Key Dimensions
Pin hole inner diameter: 85 mm (tolerance H7: 0–+0.030 mm), Trunnion outer diameter: 140 mm (tolerance g6: 0–-0.027 mm), Total length: 180 mm, Flange diameter: 160 mm (thickness: 12 mm, tolerance ±0.1 mm), Lubrication hole: M10×1.5 (depth: 25 mm), Chamfers at both ends: 2×45° (tolerance ±0.1 mm), Bushing wall thickness: 8 mm (tolerance ±0.05 mm)
Material and Manufacturing Process The trunnion body is made of 42CrMo alloy steel, tempered overall (hardness HB280–320), and nitrided (nitriding layer depth 0.5–0.8 mm, surface hardness HV850–1000); the bushing is made of tin bronze CuSn10P1, centrifugally cast, with oil on the inner surface (porosity 12%–15%); the dust seal is made of fluororubber (resistant to high and low temperatures -30℃ to +150℃).
Performance parameters: Rated radial load 320 kN, rated axial load 120 kN, operating temperature -30℃ to +150℃, compatible with Cat DEO-ULS hydraulic oil, lubrication cycle 500 hours, wear life ≥12000 hours (heavy load conditions), bushing-pin clearance 0.10–0.15 mm.
Compatible models: Cat D6T/D6R/D7R bulldozers, 966H/972H. Loader, M322F wheeled excavator, equipped with bucket 16M-0012, boom 16M-0013, and pin 8T-4120
Installation and Maintenance Points: Before installation, clean the trunnion hole, pin, and mounting surface. Bushing pressing force ≤25 kN (use a special guide sleeve to avoid lip damage). Ensure the positioning flange fits snugly against the mounting surface (gap ≤0.03 mm). Align the lubrication nozzle with the lubrication channel. Tighten the lock nut to a torque of 280 N·m. Apply thread-locking adhesive.
Maintenance Cycle: Every 500 hours, add Cat-specific lithium-based grease through the grease fitting (add until overflowing from both ends of the bushing). Check the bushing clearance (replace if radial clearance >0.3 mm). Replace the dust seal immediately if damaged.
Troubleshooting: If there is abnormal noise/increased resistance at the hinge point, prioritize checking for trunnion wear, bushing failure, blocked lubrication channels, and loose nuts. Replace components and repair mounting holes if necessary.
