Leaks in a saxophone
Before
This is the lower F key on a selmer super action 80 tenor saxophone. A very leaky F key. Working in a dimly lit room, I put my Votaw leak light (essentialy a flourescent tube on a wire) inside the body and watch what the pads do when the keys are gently depressed. The single best explanation of the process I have ever read is on Curt Alterac’s site. In fact, all repair techs should read the articles on his site – quite possibly the most thought out explanations of what we do that is available. You can find his articles, along with all the products he peddles, at musicmedic.com
After pad repair
Inhorn Band Instrument Repair 