Olds Marching Trombone valve repair

[hokieskin]

Hello,
I love playing my Olds Marching Trombone O-21, but the valves have begun to click/tink sometimes when they are depressed. I have had new pads (double thick) added, but the metal to metal click is still there. If you rotate the valve there is some play and a similar sound is heard. I think it is just wearing out., but doesn't look or feel that bad.
The valves are the spring on the bottom design with a fixed brass key on the side of the piston that runs in a keyway in the guide. I suspect the key is the wear part and needs to be replaced, but I cannot find parts for this horn anywhere.
Can anyone help me with this problem? Is this a normal sound for this design? Sad the valves can be heard on quiet passages.
I have thought to build up the keys with some brass shims, but I don't have any specs or the best method to try.
Thanks,
John

[Bonearzt]

Find a tech that will replace the metal guide with nylon.

[bigbandbone]

Nickle silver replacement guides are available, but you need an experienced repairman would need to install and fit them.

[hokieskin]

Thanks for the suggestions.
Can you also suggest who or where I can find these parts? Are they the same size as some other horn? My repairman could not find parts with his supplier using “Olds O-21”

[bigbandbone]

Thanks for the suggestions.
Can you also suggest who or where I can find these parts? Are they the same size as some other horn? My repairman could not find parts with his supplier using “Olds O-21”

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