I have quite a few good tubes with broken or not working valve stems. At one time I was able to find replacement stems both brass and rubber, but I can't find any replacement stems today. Can you guys help? Are they available?
Langs has some stems, there are two on the above linked page.
Also check out www.chaffinsgarage.com and search their PDF catalogue, they have a few stems to pick from. Easiest thing with them is to just call and tell them what you need.
This will help you with the install if you have never done it before;
You know the shorter moderns work and fit the rubber stem tubes too.