I'm having an issue with a noisy 4th valve on my Schiller Elite compensating horn. The top three valves are comparatively much quieter while the 4 valve has a sort of clank and slight rattle both when pressed completely down and when released...
Comparison of valve sounds in this video: https://drive.google.com/file/d/1uy5...w?usp=drivesdk
Pressing each valve twice in succession: 1, 2, 3, 4
Any advice on what I can do to fix it?