Article re-posted with permission from Parker Hannifin Sealing & Shielding Team. Original content can be found on Parker’s Blog.
Dovetail grooves are a great mechanism for holding O-rings in place. The retention feature makes having an upside-down or vertical face seal groove much easier. However, installing an O-ring into these grooves can be tricky without proper technique. The most important variable for installing an O-ring into a dovetail gland is making sure the seal is sized properly.
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Start the installation by directly aligning the O-ring with the gland. Proceed by pushing the O-ring into the gland at points that are 180° apart from one another. Once one section is inserted, move to the midpoint of the uninstalled area and once again, pushing at points 180° apart from one another, insert the next section. Do this until the O-ring is completely seated into the gland. Failure to size the O-ring properly for the gland or install a properly sized O-ring incorrectly can cause the O-ring to loop or buckle in one section. This loop can be the cause of mechanical damage or a trouble area for leaks. Last, when bolting or clamping the mating faces together, make sure to use a star pattern in order to achieve equal compression on all points of the seal.