17M-15-45990 17M-15-45990 O-RING

Q: why the Brake Assembly the big oring is silicon material, but usuaslly the cylinder use the balck color nbr material , in komat system?

A: The Hydraulic Cylinder: Defeating High Friction & PressureA standard hydraulic cylinder (like a boom, arm, or steering cylinder) uses black NBR or polyurethane because its primary threat is mechanical wear and tearing.High-Speed Dynamic Motion: Cylinder pistons slide back and forth constantly over long distances.The NBR Advantage: NBR has excellent abrasion and tear resistance, alongside high tensile strength (up to 3,000PSI. It can take a physical beating from moving parts without ripping.Why Silicone Fails Here: Silicone has notoriously poor tear and tensile strength. If you put a silicone O-ring as the dynamic piston seal in a high-pressure dynamic cylinder, the moving metal edges and high pressure would literally shred or "extrude" the soft silicone into pieces within days. Lower Operating Temperatures: Standard hydraulic oil systems are strictly regulated by cooling systems to stay between 60 Celsius  and 90Celsius ,well within NBR's safe zone.

Q: What are the key properties of silicone rubber for this seal?

A: Silicone offers excellent heat resistance (operating range roughly -60°C to +200°C), great flexibility even at low temperatures, and strong resistance to ozone, weathering, and aging. It’s ideal for applications with hot air, steam, or non-polar fluids, though it is not recommended for use with most mineral oils or fuels.

Q: What common issues cause O-ring failure?

A: Common causes include improper installation (twisting, pinching, or overstretching), chemical incompatibility with the fluid, excessive heat or cold leading to hardening or brittleness, surface scratches on mating parts, and using the wrong size or durometer.

 

Q: How do I install this oil seal correctly?
A: Clean the housing bore and shaft thoroughly, lubricate the seal lip and shaft with compatible oil, align the seal with the bore, and press it evenly using a seal driver until it sits flush, taking care not to damage the lip or tilt the seal.