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Seckin Makine | Producer of Wheel Rim and Hydraulic Cylinder 50 Years
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Seckin Makine | Producer of Wheel Rim and Hydraulic Cylinder 50 Years
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Cylinder Group 4Z6390/351-8446/521-7796

20 August 2026

Cylinder Group 4Z6390/351-8446/521-7796 

Wheel Loader    Caterpillar    990H, 990K

Tilt Cylinder    Bore    234,90    Stroke    1.225,00    Hydraulic Cylinder

4Z-6390/3518446/5217796

Compatible Brand: Caterpillar

Part Number: 521-7796 (5217796)

Superseded / Interchange Numbers: 4Z-6390 (4Z6390), 351-8446 (3518446)

Part Name: Large Mining Wheel Loader Bucket Tilt Hydraulic Cylinder Group / Assembly

Teknik Özellikler / Technical Specifications: Bore: 234.90 mm / Stroke: 1,225.00 mm / Weight: Not Specified (Heavy-Duty Mining Class Alloy Steel Structure & Hard Chrome Plated Forged Rod) / Hydraulic Cylinder

Compatible Machinery: Caterpillar Large Mining Wheel Loaders (990H, 990K series)

What It Does:

Serves as the primary heavy-duty bucket tilt hydraulic cylinder assembly connected to the high-lift Z-bar linkage on Caterpillar 990H and 990K series large mining wheel loaders. Powered by high-pressure hydraulic fluid across a 234.90 mm bore and 1,225.00 mm stroke, it generates massive linear mechanical thrust and pull forces to actuate bucket curling (rollback/loading) and dumping (discharging) movements during extreme open-pit mining, ore handling, and large haul truck loading cycles.

Importance:

A critical kinematic and ultra-high-thrust hydraulic drive component essential for bucket breakout force, rapid cycle times, and structural reliability in severe quarrying and large-scale mining operations. Engineered with a heavy-walled barrel, high-tensile forged alloy rod, and reinforced cylinder head structure, it effectively withstands immense axial shock forces, cyclic bending stresses, and severe hydraulic pressure spikes during aggressive face penetration into blasted rock, while advanced heavy-duty seals prevent fluid bypass under continuous high-pressure operations.

As Seçkin Makine, we manufacture this product as an aftermarket item fully equivalent to the original specifications in terms of raw materials, technical dimensions, and performance characteristics. This product comes with a 1-year warranty from the invoice date.