CAT 3J-4284 CAP

CAT 3J-4284 (3J4284) is a Caterpillar original push arm bearing cap used for bearing positioning, sealing and dust prevention between the push arm and pivot of a bulldozer. It is a key structural component that ensures the stability and protection of the push arm swing mechanism and is commonly found in the working device connection parts of D6E/D6G series crawler bulldozers. The following are the core information and key points:

Core Technical Parameters

Item Details
Part Model CAT 3J-4284 (3J4284) Push Arm Bearing End Cover, original single-piece supply, suitable for push arm pivot bearing seat end face sealing and positioning scenarios

Material
Main Body: AISI 4140 Chromium-Molybdenum Alloy Steel, tempered (hardness HB 280-320), tensile strength ≥900MPa; Sealing Surface: Integrated Nitrile Rubber (NBR) Sealing Ring, oil resistance ≥120℃ mineral oil, anti-aging life ≥5000 hours

Key Dimensions
Outer Diameter 180mm, Inner Diameter 120mm, Thickness 35mm, Bolt Hole Distribution Circle Diameter 150mm, 6 M16 threaded holes evenly distributed, Bolt Preload Torque 120N・m; Sealing Groove Diameter 125mm, Groove Width 5mm, O-ring Wire Diameter 4.8mm; Installation Positioning Stop Diameter 140mm, Tolerance H7 Compatible with CAT D6E, D6E SR, D6G SR, and D6G2 LGP/XL bulldozers, 3306 engine-equipped pusharm mechanism. Used for pivot bearing positioning and end cover sealing/dustproofing for the pusharm-to-frame connection. Compatible with 3J4359 pusharm and support assembly.

Performance Parameters: Rated load pressure 1.5MPa, operating temperature -40℃ to 120℃, sealing protection level IP65, axial clearance after bolt tightening ≤0.2mm, impact load resistance ≥50kN, cyclic fatigue life ≥8000 cycles.

Core Functions and Structure:
Bearing positioning and anti-loosening: Bolted to the pusharm bearing seat end face, fixing the inner/outer ring of the pivot bearing, limiting axial movement of the bearing, preventing component loosening and wear under impact loads, and ensuring pusharm swing accuracy.

**Sealed for Dust and Leak Prevention:** Integrated O-rings and dust lips prevent mud, water, and dust from entering the bearing clearance, preventing grease leakage, extending bearing lubrication cycles and service life, and suitable for dusty and humid conditions.

**Load Dispersion and Buffering:** The alloy steel body disperses the radial load during push arm swing, avoiding localized stress concentration in the bearing. Combined with stop-type positioning, it reduces the risk of bolt loosening due to vibration and improves the stability of the connection.

**Ease of Maintenance:** A pre-drilled grease filler hole (M10×1.5) allows for periodic grease replenishment. Bearing maintenance can be completed without disassembling the end cover, reducing maintenance time.