Capillary tube fitting leak

[billwill]

When you said a leak there, my first thought was that you meant a leak of the liquefied gas (ether) inside the bulb. That is hard to fix.

But you meant a water leak... The simplest fix for that is like any plumbing leak, wrap a few turns of Teflon white plumbers tape around the fitting and screw it on reasonably tight, but not spanner tight.