I am totally prepared to be shot down in suggesting this but here goes anyway. I am assuming that the "saddle tank" is just a water holder and not a pressure vessel. What about unsoldering the bushes and cleaning up any residues as best as possible until you are back to original metal. Then use high melting point solder……Comsol, or similar ….to resolder the bushes. Then use a lower melting point solder to fix the ends. I think that this is called step soldering.

Mick

Bill, I would not attempt to clean up the soft solder and then silver solder, the smallest speck of soft solder will produce a hale. To re-melt soft solder you need more heat than used to make the joint in the first place. Brass sheet has a nasty habit of buckling when heated beyond the heat for soft soldering. Trust me I know, and it was expensive. The cause was trying to make all the joints in a tank in one go. Plan ahead, make one joint, allow to cool then clean the next joint etc etc etc.

Don't unsolder the bushes, make some sort of heat sink for them, and with carefull soldering with a lower temp solder(electrical rosin cored). Pre tin the joints, and I would use a large soldering iron, if I had to use an electric iron I would use the 175W iron to get the heat into the joint quickly.

Ian S C