This o-ring has to be tough enough to handle the high heat at the injection pump. If you see oil leaks around the area of the rack damper (located on bottom at rear of injection pump) then replace this o-ring.
Also recommend when replacing the rack damper with the upgraded bolt. O-ring is now included with our rack damper bolts. To order a new adjusting bolt look below to order.
Location of o-ring on bolt: