Unfortunately in this case solder is not up to the job, you either need to weld it or buy a new gearbox. In case you're wondering... I've been there, done that and got the tee-shirt. Best to tell you now before you refit the expander...![]()
Thanks for the advice, it was a give it a go thing! It's soldered well and should be easier to move once serviced but it's in my budget should I need to buy new, or I guess I could get it braised as it's brass.