ingredients

1. short length of 8 mm brass tube from B&Q
2. small ball bearing
3. small copperdisc made from coper pipe, drilled
4. spring from ball point pen
5. short length of copper brake tubing
6. salt and pepper
7. solder.

method
drill 3mm hole in disc and solder onto end of tube. use 4 mm drill on inside to counter sink hole.

fit ball bearing and spring. Fit short length of brake pipe so that spring is under tension. season to taste. peen (?) over end of tube to keep brake pipe in place.

enjoy.

[Edited on 8/5/08 by 02GF74]

do we have a picture to see

Is it a fuel tank breather?

I have been after something like this for ages.....it is the tips that I like...an ordanary biro pen spring and ball bearing....the other stuff I already have.....

From the instructions this is what I think it should look like....it is correct...

ps...never did spring drawing at school....

One way vavle

Maybe a daft question, but what do commercially produced check valves cost over there? Half inch check valves with a brass body only cost about a quid over here.. I wouldn't go through the trouble of scavenging parts just to save a few pence..

yes , just buy an MBC of ebay , or a pressure relief valve .

Not wishing to 'P on your chips', but what you suggest will more than likely not seal efficiently therefore you will be the proud owner of a 'tube'.
As above check valves are available for pennies, Schrader valves can be used to control flow if it's breathers you are referring to, so at the end of the day I wouldn't bother trying to save money on things like this.

Regards Mick

Hi Also important to remember that fuel tanks need to breath IN and OUT. One way valves can give problems also.

Cheers Matt

yes - just like the diagram.

I tested it by blowing/sucking and it sealed fine.

Fitted inside the fuel hose, filled up to the brim and not a drop of petrol spilled so I would conclude that is pretty successful.

I doubt I can get anything that would fit as well and as small locally so there is postage on top.

as for breathing both ways, I reckon the hole I mentioned in the filler will do that - the breather fitted I guess is redundant.

The reason for fitting the valve was that since there is no way to tell when the tank is full, it is too easy to put in another 2 or 3 pints before it start to wee out and petrol prices as they are now, that is too much money to waste not to mention dangerous.

I think someone suggest use fish tank valve but I did not want to spend the 2 or more quid plus not to mention petrol to get to the fish place and I was not sure if the plastic would like petrol nor if it would fit.

[Edited on 8/5/08 by 02GF74]