Rotor valve bumpers falling out (Yamaha)

[GMB]

Has anyone had trouble with rubber valve bumpers falling out on Yamaha trombones and have any fixes that don't involve filing metal? I've had the originals and replacements fall out way too easily. I've just had silicone ones put in so we'll see how they hold up... I don't care if they wear out as long as they don't fall out before that. While I was with my tech he showed me how Alexander horn bumper holders are grooved and they look just about impossible to have a bumper fall out, in contrast to my Xeno bass where they're smooth and don't really look to grip the bumpers in any meaningful way. I've never had this happen on my Conn or any other trombone.

[tbonesullivan]

That's odd, I have two Yamaha trombones and haven't had any issues. Did you use large enough pieces of rubber? They are supposed to "squeeze" in there and then you adjust the size.

[GMB]

Yes, the replacement ones were larger because my tech concluded that the original ones were too small/loose, and because one of my valves actually isn't 90 degrees (on the F attachment if it's actuated to where the lines on the valve cap/cover show it should be it actually overshoots the entrance to the valve so I need a thicker bumper at least there). After they popped out during two separate performances my tech opted to try silicone ones. The original ones had also jumped out a couple times while practicing but I could just push them back in by hand (though AFAIK they should be tight enough that you should have to disassemble the clasp and push them in with a screwdriver, correct?). If I continue to have problems I might even try white tack because it's getting ridiculous as is.

[GMB]

The rubber ones even though they're oil resistant it's almost like they just got too slippery once in contact and would just pop out (and couldn't get them to stay back in even with a screwdriver)

[marccromme]

Easy. Use the soft plastic cylinders used in heat glue guns, the come in different sizes, and use a glue gun to glue them into the horse shoe. You might want to roughen up the contract surfaces a bit using some sand paper first. That will hold nicely.

[ssking2b]

Put some clear finger mail polish in the socket the bumper goes into. Immediately out in your neoprene bumpers and let dry for about 10 minutes. The fix is done!

[Matt K]

Put some clear finger mail polish in the socket the bumper goes into. Immediately out in your neoprene bumpers and let dry for about 10 minutes. The fix is done!

This is what I recommend. Or not-clear nail polish if you want something to visibly see if the coating has worn off.