CAT 527-7491 Push Arm Trunnion

CAT 527-7491 is a Caterpillar bulldozer/loader pusharm trunnion (solid alloy steel shaft), adapted for the pusharm and rocker arm hinge joint of D6/D7 series bulldozers and 966M/972M loaders. It is used to transmit pusharm loads and withstand combined stresses. The following is professional structured information.

Core Parameters (Professional Version)

Project Details
Basic Attributes
Model 527-7491, Solid Pusharm Trunnion, 2 pieces per unit, compatible with Cat D6N/D7E bulldozer pusharm and rocker arm hinge points, 966M/972M loader bucket pusharm trunnions, bearing radial + alternating axial loads, suitable for heavy loads (≤200 kN) and low-speed oscillating conditions (≤5°/s)

Key Dimensions
Diameter 85 mm, Total Length 380 mm, Journal Length 120 mm, Mounting Step Diameter 95 mm, Thread Specification M24×2 (both ends), Locating Pin Holes φ12 mm (2, symmetrically distributed), Center Distance 320 mm, Surface Hardness HRC45–50, Roughness Ra≤0.8 μm

Material and Process
Material is 4140 chromium-molybdenum alloy steel, overall quenching and tempering treatment (tensile strength ≥900 MPa), journal surface induction hardening HRC58–62, roundness ≤0.005 mm, straightness ≤0.01 mm/m, thread accuracy at both ends 6g, locating pin hole perpendicularity ≤0.02 mm

Performance Parameters: Rated static load ≥350 kN, fatigue limit load ≥280 kN, allowable swing angle ±15°, suitable working temperature -40℃ to +120℃, suitable bushing inner diameter 85 mm, fit clearance 0.10–0.15 mm, single piece weight ≈28 kg

Compatible Models: Cat D6N/D6T/D7E bulldozer pusharm, 966M/972M loader bucket pusharm, matching bushing 175-4442, suitable trunnion seat hole 95 mm, installation torque M24×2 thread is 180–200 N・m

Installation and Maintenance Points: Clean the trunnion, bushing, and trunnion seat before installation. Bushing inner diameter tolerance… H7, trunnion housing bore tolerance J7, surface free of burrs and rust; the shaft and bushing use a clearance fit (φ85 H7/f6), with a clearance of 0.10–0.15 mm to ensure flexible swing.

Use a crane to lift the trunnion, align it with the locating pin hole, and tighten both ends with M24×2 bolts at a torque of 180–200 N·m. After installation, check the swing resistance (≤500 N), ensuring there is no jamming or abnormal noise.

After assembly, add Cat 106-9900 extreme pressure lithium-based grease through the grease fitting. Replenish lubrication every 500 hours, adding enough grease to overflow from both ends of the bushing each time to avoid dry friction.

Every 1000 hours, check the trunnion for wear (journal wear > 0.2 mm), deformation (straightness > 0.02 mm/m), or cracks. Replace immediately if any abnormalities are found to prevent push arm breakage.