I was topping my brake fluid off today as to clear the erroneous "brake" and traction control lamps that tend to engage under acceleration when it's low. While doing so, I noticed this little plastic piece which appears to have belonged to the the nut just forward of it at one time. I tried to snap it back into place behind the nut, but no luck. Any ideas?

 

The white ring? Leftover from production. It holds the spring lock in position on the AC line.

 

Yeah you dont need it