CAT 314-8727 Flange Yoke Trunnion

CAT 314-8727 is a Caterpillar genuine YM series welded trunnion, suitable for the boom, rocker arm, and frame articulation parts of loaders, excavators, and other equipment, used for heavy load transmission and positioning pins. The following is pure original data and does not include replacement parts information for Cat®…

Core Technical Parameters (Raw Data)

Item Details
Basic Attributes
Model 314-8727 (YM Series), Type: Welded Single Trunnion, Material: SAE 4140 Alloy Steel (Integral Forging + Surface Hardening, Hardness HRC 50-55), Single Weight: 48.6 kg, Suitable for Grease Lubrication, Operating Temperature: -30℃ to +120℃, Radial Load Capacity ≥680 kN, Torsional Strength ≥1200 N・m

Key Dimensions (Metric / Imperial)
Pin Fit Diameter: 100.0 mm (3.937 in, Tolerance +0.02/-0 mm), Weld Base Diameter: 180.0 mm (7.087 in), Trunnion Total Length: 220.0 mm (8.661 in, Tolerance ±0.2 mm), Trunnion Journal Length: 85.0 mm, Weld Surface Thickness: 25.0 mm, Chamfers at Both Ends: 3×45°, Center Hole Diameter 12 mm (lubrication channel)

Performance Parameters: Coefficient of friction ≤0.1 (grease lubrication), fatigue life ≥2×10⁶ cycles, coaxiality tolerance ≤0.05 mm, bushing clearance 0.06-0.09 mm

Structure and Adaptability Characteristics:

Heavy-duty welded structure: Precision machined after integral forging, journal surface hardened for uniform hardness, suitable for high-frequency oscillation and heavy-duty conditions. The welded base has a positioning groove to ensure weld coaxiality and strength, reducing stress concentration (Cat®…).

Integrated lubrication design: Center hole + radial oil outlet, combined with spiral lubrication grooves, ensures uniform grease distribution, reduces the risk of dry friction, and is suitable for long-term continuous operation.

Machine Compatibility: Compatible with the boom lower hinge point and rocker arm to frame connection point of loaders 950M, 962M, 972M, excavators 320GC, 323GC, etc. Compatible with bushing models 365-0387, 599-8875, pin model 207-6055, etc. (Cat®)…

Installation and Maintenance Points (Original Data)

Installation: Clean the welding surfaces and trunnions to remove oil and rust; check journal runout with a dial indicator (≤0.05 mm), and confirm the fit dimensions with an inside gauge.

Use argon arc welding with a welding current of 180-220 A and an interpass temperature ≤150℃. After welding, maintain the temperature for 60 minutes and allow to cool slowly to prevent cracking; after welding, finely grind the journal to ensure a surface roughness Ra ≤0.8 μm.

Install the bushing and pin, and apply NLGI 2 lithium-based grease until it overflows from both ends.

Maintenance: Check trunnion wear every 800 hours. Replace immediately if journal wear > 0.2 mm, or if surface peeling or cracks appear.

Replenish with grease every 200 hours to prevent dry friction from causing the journal and bushing to sinter.