1. Size does not match
phenomenon
After 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 damage
phenomenon
O-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 twist
phenomenon
After 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.