O-rings can be sheared, nicked, cut, torn, twisted, turned & overstretched during installation which may cause leakage and even damage to parts. To prevent this from happening, make sure the O-ring conforms to the required dimensions. To avoid spiral failure, slide the O-ring into place (don’t roll it). Avoid overstretching. Use lubricant and cover threaded parts which might tear the O-ring. Avoid sharp edges on glands or components. And finally, don’t use excessive force.