What new fuel pipe fixings for old fuel tank help?

[Captain Crisp]

Hi,
I'm trying to source new attachments for the outlets on my old SS fuel tank. There are two outlets from the bottom of the sump. The existing fixings are 1/2 inch OD and slightly tapered. I want to replace both.
One is to drain the sump, the other is to lead fuel into the pipe.
What sort of fixings set-up does the panel recommend? I'm not too sure what the names for these types of fixings is, so even that would be very helpful.
Many thanks,
Crisp

Current fixings:



Base of fuel tank:

 

[vyv_cox]

Water lying at the bottom of my tank had corroded the threads of the drain plug, causing it to leak. The threads were very fine, maybe UNF or something similar. I tapped the bosses to the next size up in BSP, 3/8" from memory. Fittings for this size are widely available, valves, hose tails, blanks, whatever you need.

It is possible that yours are already BSP, check the OD and TPI against a chart like this BSP / BSPT Thread chart | British Metrics

The fittings you have look fine but to replace take them to a plumbing outlet and ask.

 

[Captain Crisp]

Many thanks - I was thinking that I might attach a tap to the sump outlet rather than just a plug. Thought it might make draining it a tidier job. Any reason not to?
Thanks

 

[vyv_cox]

Many thanks - I was thinking that I might attach a tap to the sump outlet rather than just a plug. Thought it might make draining it a tidier job. Any reason not to?
Thanks

The only possible problem is sealing. The fitting you have appears to be tapered although it has a sealing washer, not sure if this was on the valve side?. A valve used directly into the tank will probably have a parallel thread, in which case you will definitely need a sealing washer, copper or Dowty between the flat face of your tank and the valve.

 

[penberth3]

Many thanks - I was thinking that I might attach a tap to the sump outlet rather than just a plug. Thought it might make draining it a tidier job. Any reason not to?
Thanks

It's a good idea. I would fit a plug to the outlet of the tap as "belt and braces".

 

[Captain Crisp]

The only possible problem is sealing. The fitting you have appears to be tapered although it has a sealing washer, not sure if this was on the valve side?. A valve used directly into the tank will probably have a parallel thread, in which case you will definitely need a sealing washer, copper or Dowty between the flat face of your tank and the valve.

Weirdly the fittings were in the wrong way round, as in the plug was on the fuel outlet and the pipe fitting was taking fuel from the bottom of the sump... Which may explain why it got blocked....

The threads seem to be slightly different... Neither of the old fittings seem to fit the 'right' hole as snugly as they do the 'wrong' hole... Which is perhaps why they were that way round?

I'm going to take the tank and fittings to a plumbers outlet as advised... See what they say...

Many thanks