Sealing Excellence, Securing Industry

CFKS Heavy Duty KDAS Oil Seal 35*25*29.1 Hydraulic Piston Seal DPM Compact Seal for Cylinder

The CFKS KDAS 35*25*29.1 compact hydraulic piston seal is an all-in-one, double-acting sealing system engineered to replace multi-piece packing assemblies in medium to heavy-duty hydraulic cylinders. Designed for high pressure retention and minimal drift, this five-piece dynamic assembly delivers superior extrusion resistance and reliable fluid power containment across demanding industrial applications.

  • 5-Piece Integrated System: Features an elastomer sealing element, two thermoplastic split anti-extrusion rings, and two angular guide rings for complete stability.

  • Compact & Space-Saving: Fits short, single-groove pistons to reduce overall cylinder weight, length, and machining costs.

  • Superior Pressure Protection: Built to handle operating pressures up to 35 MPa without gap extrusion or blow-by under sudden shock loads.

Find your sealing solution with CFKS — contact us for a quote.

Product Name KDAS Compact Hydraulic Piston Seal Specification 35*25*29.1 mm (Custom sizes supported)
Material NBR / FKM + POM / TPC-ET Feature High pressure resistance, Anti-extrusion
Work Temperature -30℃ to 220℃ (Material dependent) Usage Excavators, Presses, Loaders, Forklifts, Hoists
Hardness 70 – 85 Shore A Type DPM Double-Acting Five-Piece Compact Seal

The KDAS dynamic piston seal operates on a pressure-energized multi-element mechanism specifically designed for double-acting hydraulic cylinders. The central NBR elastomer profile acts as the primary sealing ring, maintaining initial contact stress against the cylinder bore even at zero pressure. As hydraulic fluid pressure increases, the elastomeric element energizes and transfers fluid force radially outwards against the cylinder wall and laterally against the thermoplastic support rings. The integrated L-shaped guide rings absorb side loads and prevent metal-to-metal contact between the piston and cylinder tube, while the anti-extrusion backup rings close the radial clearance gap to prevent seal biting under heavy cyclic impulse pressures.

Material integrity directly dictates sealing longevity in harsh fluid power environments. CFKS manufactures the primary elastic element using high-grade NBR (70-80 Shore A) for excellent oil resistance, low compression set, and optimal elasticity in standard mineral-based hydraulic oils. For extreme chemical exposure, high-frequency friction heat, or elevated operating environments, FKM options are available to withstand fluids up to 200°C. The wear-resistant guide rings and backup rings utilize modified polyester TPC-ET or POM, providing high tensile strength, low friction coefficient, and exceptional resistance to cold flow under continuous high-load operations.

The KDAS compact profile significantly simplifies assembly compared to traditional multi-piece V-packings. Featuring a split design on both the anti-extrusion backup rings and wear rings, the entire assembly can be snapped sequentially into a closed piston groove without requiring specialized expanding tools or complex cylinder disassembly. During installation, ensure the piston housing groove is thoroughly deburred, cleaned, and lubricated with clean system fluid to avoid cutting the primary elastomer seal lips. Regular maintenance checks should monitor system fluid contamination and surface finish conditions; replacing worn compact seals proactively prevents cylinder scoring, internal fluid bypass, and unplanned hydraulic pressure dropouts.

Frequently Asked Questions (FAQ)

Why does my CFKS oil seal fail prematurely? Common causes and prevention tips2025-06-26T15:44:39+08:00

Premature oil seal failure can result from improper installation, poor shaft finish, incorrect material selection, or excessive pressure. To prevent this, ensure the shaft surface is smooth and within tolerance, use correct tools during installation, and choose seals made from materials compatible with your media and temperature.

How to correctly install a CFKS industrial oil seal to avoid leakage2025-06-26T16:04:32+08:00

Always clean the shaft and bore before installation. Use appropriate seal drivers to avoid deformation. Lubricate the lip before fitting to reduce friction during the first rotation. Ensure the seal is seated evenly and not tilted to avoid leaks.

What to do when your CFKS hydraulic seal is leaking under pressure2025-05-20T16:33:14+08:00

Check if the pressure exceeds the seal’s rated limit. Examine for wear, hardening, or improper installation. Replace the seal if damaged, and consider upgrading to a high-pressure CFKS seal variant. Also, verify that the housing and shaft are properly aligned.

How to choose the right CFKS oil seal for extreme operating environments2025-05-20T16:34:39+08:00

For high temperatures, aggressive chemicals, or abrasive environments, choose CFKS seals made of FKM, PTFE, or high-performance elastomers. Consider using seals with protective dust lips or metal casing. Our team can recommend the best fit for your application.

CFKS Seal Manufacturing Co., Ltd.
https://cfksseals.com/
 Email: cfksnacy@gmail.com  Mobile/WhatsApp/Wechat: (86) 188-3097-5917
DAS/KDAS Size List
Type SIZE
DAS/KDAS Combination Seal 20*11*17.7
DAS/KDAS Combination Seal 22*13*17.7
DAS/KDAS Combination Seal 25*15*20.5
DAS/KDAS Combination Seal 25*15/1*29.1
DAS/KDAS Combination Seal 25*16*17.7
DAS/KDAS Combination Seal 28*19*17.7
DAS/KDAS Combination Seal 30*21*17.7
DAS/KDAS Combination Seal 32*22/1*20.7
DAS/KDAS Combination Seal 32*22*29.1
DAS/KDAS Combination Seal 32*24*21.9
DAS/KDAS Combination Seal 35*25/1*20.7
DAS/KDAS Combination Seal 35*25*29.1
DAS/KDAS Combination Seal 40*24*31.1
DAS/KDAS Combination Seal 40*26*20.7
DAS/KDAS Combination Seal 40*30*29.1
DAS/KDAS Combination Seal 40*30/1*20.5-
DAS/KDAS Combination Seal 40*30/2*20.5+
DAS/KDAS Combination Seal 42*28*20.7
DAS/KDAS Combination Seal 45*29*31.1
DAS/KDAS Combination Seal 45*31*20.7
DAS/KDAS Combination Seal 45*35*29.1
DAS/KDAS Combination Seal 50*34/1*26.7
DAS/KDAS Combination Seal 50*34*31.1
DAS/KDAS Combination Seal 160*135*44.4
DAS/KDAS Combination Seal 160*143*40.9
DAS/KDAS Combination Seal 160*138*36.7
DAS/KDAS Combination Seal 165*140*44.4
DAS/KDAS Combination Seal 170*145*50.8
DAS/KDAS Combination Seal 175*150*50.8
DAS/KDAS Combination Seal 180*155*50.8
DAS/KDAS Combination Seal 180*150*48.1
DAS/KDAS Combination Seal 185*160*50.8
DAS/KDAS Combination Seal 190*165*50.8
DAS/KDAS Combination Seal 195*170*50.8
DAS/KDAS Combination Seal 200*175*50.8
DAS/KDAS Combination Seal 210*185*50.8
DAS/KDAS Combination Seal 220*190*48.1
DAS/KDAS Combination Seal 220*195*50.8
DAS/KDAS Combination Seal 230*205*50.8
DAS/KDAS Combination Seal 240*215*50.8
DAS/KDAS Combination Seal 250*225*50.8
DAS/KDAS Combination Seal 250*220*48.1
DAS/KDAS Combination Seal 260*235*60.5
DAS/KDAS Combination Seal 275*250*48.3
 

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