Re: Re: Re: Re: Re: Re: Re: Leaky Valves


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Posted by John Swensen on July 07, 2000 at 13:18:43:

In Reply to: Re: Re: Re: Re: Re: Re: Leaky Valves posted by MF on July 07, 2000 at 10:37:38:

1) It can be a very simple replacement, particularly if the guide screws in. Ferrees sells replacement guides (with a 3-48 thread, I think). Be sure to file the guides OFF the valve.

2) That guide doesn't look terribly worn to me. How much play is there? I wouldn't get too upset about enough play to be able to make clicking sounds by gently twisting the valve by its cap (when the valve in its normal position).

3) You can check the alignment simply and cheaply by buying a mouth mirror at a drug store (plastic mirror on a plastic stick, often packaged with a metal pick for less than $5.00).
To check valves 1 and 3, remove valve 2 and the bottom cap, insert the mirror, shine a small flashlight down the valve casing, and look through the port between valves. You should be able to check alignment in the up, down, and side-to-side directions. It may help to cut the handle off the mirror, file a 45-degree angle on the end, and glue it onto the back of the mirror.

4) Vertical alignment can be corrected by replacing felts and/or corks, possibly sanding the corks to final thickness (OFF the valve, of course). For most types of felts, you can expect to replace them once a year, or more often if they get wet. Ferrees carries felts and corks and they will sell to anyone. Dillon Music has some really nice, Besson, rubberized felts that seem to last much longer than ordinary felt. If you save the old felts and keep them in order, you can always go back to the way the horn was before.

5) Lateral alignment can be adjusted by "custom filing" a new guide. Suppose you need the valve twisted clockwise a bit for perfect alignment. Using a new, sacrificial guide, file it to fit the slot, then continue to file off more of the "clockwise" side of the guide until the ports line up when twisted clockwise. Finally, file another guide to match the sacrificial guide on the clockwise side, then file the other side until the guide fits the slot without binding. Depending on how accurately you can measure and file, this may require several tries. Buy lots of guides before starting.

6) If you have any doubts about your abilities to pull this repair/adjustment off without damage, don't attempt it. Don't ever file with the guide on the valve. Don't ever force anything. If you start to get into trouble, STOP, put on your most sheepish face, and pay an experienced repair person to get you out of trouble without ruining your horn.



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