Sealing Excellence, Securing Industry

CFKS UN Oil Seal 40*50*6 UN Hydraulic Lip Seal High Pressure UN Piston Seal for Cylinders

Engineered for demanding dynamic applications, the CFKS UN 40*50*6 Hydraulic Seal delivers reliable single-acting fluid retention across heavy industrial machinery. Its symmetrical polyurethane lip configuration ensures optimal sealing performance on both internal rod and external piston arrangements while resisting severe pressure spikes.

  • Symmetrical Seal Design: Serves interchangeably as a rod or piston seal in standard compact cylinder grooves.

  • Extreme Pressure Resistance: Built to withstand operating system pressures up to 31.5 MPa without extrusion.

  • Superior Wear Performance: Formulated from high-grade PU to prevent premature degradation from dynamic friction.

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

Product Name CFKS UN Oil Seal 40*50*6 Work Temperature -20℃ to 220℃ (Material Dependent)
Specification 40mm * 50mm * 6mm (Customization Supported) Usage Excavator Cylinders, Injection Molding, Hydraulic Presses, Dump Trucks, Agricultural Rams, Crane Hoists
Material PU / NBR / FKM Hardness 85 – 92 Shore A
Feature High Pressure & Wear Resistance Type UN Hydraulic Lip Seal (Rod & Piston)

 

 

The UN profile operates as a single-acting lip seal engineered for reciprocating hydraulic cylinder rods and pistons. Featuring symmetrical inner and outer sealing lips with equal height, the seal creates an initial static pre-load against the housing groove and shaft surfaces. As hydraulic working pressure increases, the fluid force expands the flexible seal lips, creating an automatic self-sealing pressure-energized action. This mechanism ensures zero fluid bypass under high dynamic loads while maintaining smooth stroke motion and minimal breakout friction.

Formulated from premium PU, the CFKS UN 40*50*6 seal exhibits high tensile strength, exceptional tear resistance, and minimal compression set. Standard 90 Shore A polyurethane provides superior structural stability against gap extrusion under high hydraulic pressure spike conditions. For aggressive working environments, FKM alternatives are available to maintain elastomer elasticity when exposed to synthetic hydraulic fluids, high temperatures, and harsh industrial chemicals.

Designed for straightforward press-fit setup, the flexible PU structure allows for easy snap-in mounting into closed grooves without requiring complex disassembly tools. To avoid lip damage during assembly, clean all cylinder housing surfaces, deburr incoming chamfers, and apply a compatible hydraulic lubricant before positioning. The low-friction compound minimizes heat buildup during operation, significantly extending maintenance cycles and reducing unplanned equipment downtime in continuous industrial operations.

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
TCV TYPE SEAL SIZE LIST
SizeTypeMaterialColor
12*30*5BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
13*19*2.5BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
14*25*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
16*30*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
17*30*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
17*30.3*8BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
17*32*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
17*35*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
17.46*28.58*5.7/6.3BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
18*30*10BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
18*30*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
18*35*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
18*35*8BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
18*35*9BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*27*5BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*30*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*32*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19.5*33*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*35*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19.5*30*6/6.5BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*35*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*35*8BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*35*3/7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*37*6.5/7.5BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
19*44.45*6.35BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
20*32*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
20*32*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
20*35*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
20*40*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
20*47*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
20*47*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
22*30*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
22*32*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
20*32*6.5/8.6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
22*35*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
22*36*10BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
22*36*7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
22*42*10BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
24*34*6.3BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
24*38*6/7BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
24*38*8BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
24*55*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
25*33*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN
25*35*6BABSL CFW / TCV OIL SEALNBR/FKMBLUE/BROWN

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