Originally Posted by
UCFEuph
It appears the bottom of my valve somehow got bent and I'm guessing that may be the culprit.
If what you're referring to is what appears to be a slight deformation of the bottom of the valve casing (on the right side as we're viewing the picture?), that sort of thing is very easy for a repair tech to fix. Difficult to imagine how/when it would have happened since I can't see how it could have happened with the bottom cap on it. And it's low enough that it's not obvious to me that it is really interfering with the bottom of the piston. So that MAY not be the cause of your problem.
Also, if the piston moves freely until it's firmly tightened down, that also suggests that something that low in the casing may not be the problem. One thing I'd do is to take the finger button off, take the top cap off, take the spring out, and see if you can gently move the piston up and down in the cylinder. If you can get your valve guide off, see if the piston rotates freely in the cylinder at each depth. Be VERY gentle with this and stop at the first sign of any rubbing or tightness. That should tell you at what point the piston is starting to stick. If it doesn't stick under those conditions, that suggests that there is some alignment problem occurring when you tighten down the top valve cap -- which suggests that something is probably bent in a minor way. The most likely culprit would be the valve stem -- and it doesn't take much. Be sure that your valve stem and finger button are not loose as well.
You could also test this by switching the valve stem with one of the others and seeing if you still have the problem. You could also (not at the same time) switch the valve cap with one of the others (assuming they're the same size), and see if you still have the problem.
In my own experience, when this has happened to me it's always been a problem with the valve not being completely clean or else there was enough slop in the threads to cause a minor alignment issue when fully tightened -- but I would be surprised to see that in a Besson. However, you should look at your top valve threads and valve cap threads to see if anything looks peculiar.
Gary Merrill
Wessex EEb Bass tuba (DW 3XL or 2XL)
Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
Amati Oval Euph (DE 104, Euph J, J6 euph)
1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
1947 Olds "Standard" trombone (Olds #3)