Think the seals on your Black Hawk’s primary servos are missing after inspection? Maybe not.
The primary servos went through a recent configuration change that included a more environmentally-friendly chrome plating process and improved seals. Upon inspection, the seals appear to be missing. This causes mechanics to prematurely remove perfectly good servos, NSN 1650-01-625-0164, for missing seals.
With the change, the old black wiper seal was replaced with a V-spring energized rod seal. The new seal is slightly recessed, making it trickier to see.
So during visual inspection, don’t immediately remove or reject a primary servo if you can’t see the seal. Instead, check closer for the new V-spring seal. If it’s there, the servo is good to go.
What the old seal looks like on the servos
What the preferred (new) scraper seal looks like when installed
Another view of the scraper seal visible spring, also called a v-spring rod seal
And here’s more good news: There’s no need to replace all the servos just because you received one of the new ones. The new servos can be installed alongside legacy servos on the same aircraft.