I have a 2012 and a 2016 both tuxedo black both non pp. The 2016 sho is making a loud hissing coming from I believe the check valve the grey one directly to the left of the brake fluid reservoir. My 2012 doesn't make this noise and the 2016 wasn't making the loud hiss prior or if it was it wasn't as prominent.if I disconnect the hose from it you can tell that this is where it's coming from. Is this normal?