Faq
O-ring installation common problems and countermeasures
1. Size does not matchphenomenonAfter installation, the O-ring is overstretched or under-compressed, resulting in leakage.reason：Groove size design errors (e.g. width and depth not meeting ISO 3601 standards).O-ring inner diameter does not match shaft diameter/aperture.solve：Verify the groove size (recommended compression ratio: 10-30% for static seals, 8-15% for dynamic seals).Measure the cross-sectional diameter and wire diameter of the O-ring with a measuring tool to ensure that the tolerances meet the requirements (e.g. AS568 standard).2. Installation damagephenomenonO-ring surface scratches, cuts or tears.reason：The edge of the installation tool is sharp or improperly made.Force through threads, burrs, or acute angles.solve：Use a blunt nylon mounting tool or a copper guide sleeve.Chamfer the shaft end and orifice (recommended chamfer angle 15-30).Step 3 Twist or twistphenomenonAfter the O-ring is installed, it is twisted in a twist shape, and the local stress is concentrated.reason：The rotation angle is too large during installation.Insufficient lubrication results in uneven friction.solve：Adopt "push-in" installation to avoid rotation.Apply silicone grease or perfluoropolyether (PFPE) lubricant to reduce friction.
Oil seal installation typical problems and repairs
1. The spring falls off or shiftsphenomenonThe oil seal spring is separated from the sealing lip and loses the pre-tightening force.reason：No special tools were used during installation, causing the spring to eject due to mechanical impact.The oil seal is improperly stored and the spring pre-installed position is loose.solve：Use an oil seal installation tool with a guide sleeve (e.g. SKF TTOOL series).Check whether the spring is stuck in the groove of the sealing lip before installation.2. Sealing lip flangingphenomenon: The oil seal lip is turned out and in poor contact with the shaft surface.reason：The shaft end is not chamfered, and the lip is deformed due to forced pressing.Installation direction is incorrect (e.g. with the dust lip facing the media side).solve：Make sure that the chamfer of the shaft end is smooth (roughness Ra0.8 μm).Confirm the direction of the oil seal: the main sealing lip faces the sealed medium (such as the transmission oil seal main lip faces inward).3. Shaft surface damagephenomenonShaft scratches cause accelerated wear on the lip of the oil seal.reason：The surface roughness of the shaft exceeds the standard (the oil seal requires Ra 0.2-0 μm).Hard particles (such as metal shavings) are embedded in the sealing lip.solve：Install the front polished shaft surface and apply grease protection.Clean the shaft and oil seal to avoid contaminants from entering.
General installation errors and standardized operation
1. Improper selection of lubricantWrong practiceUse regular butter to lubricate PTFE seals, causing the material to expand.standard operation：O-ringSilicone grease, fluorinated lubricants (e.g. Krytox).oil seal: Lubricating oil compatible with the medium (e.g. lithium-based grease high temperature resistant oil seal).2. Violent tapping installationriskSeal deformation, metal frame oil seal cracking.correct way：Use hydraulic or mechanical presses to apply even pressure.The installation pressure of the oil seal is 0.5MPa to avoid overload.3. Lack of environmental controlhidden dangerDust and humidity affect the sealing performance.measure：The cleanliness of the installation environment is ISO 14644-1 Class 8.The humidity is controlled at 40-60% to prevent the rubber from absorbing moisture and expanding.
Post-installation inspection and maintenance
1. stress testingmethod：Static seal: 1.5 times the working pressure for 30 minutes, pressure drop 5%.Dynamic seal: step up pressure test, observe the leakage point.2. Leak diagnosticsCommon leak types：interface leakageThe sealing surface is uneven, and the groove needs to be reprocessed.osmotic leakageMaterial is incompatible with the medium, replace the sealing material.3. Regular maintenancesuggestion：Check seal compression set every 500 hours (refer to ASTM D395).Under high temperature conditions, replace the elastomer seals every 6 months.