Had me foxed for months too, but I've just done it! It now springs shut just like new, which gives me a childish pleasure. The spring can go either way round - trial & error will show you which is right; I can't remember which one worked in the end(!) SO:
First take a good look at the coloured end cap. Down the middle of the inside there is a small ridge. There is a slit in the ridge at one point. This is the key. remember this when you get to the end. Fit the spring by putting the two ends in the two tiny holes at the cap end. Easy part done. Now fit the coloured end cap one clip at a time, being careful not to dislodge the spring. This is the hard part. Finally the clever part: Insert a small screwdriver into the gap between cap and hose, and slowly ease the spring down into the slit in the coloured cap, by keeping the screwdriver on the ridge, and easing the spring down with it. If it is impossible, take it apart, and try the spring the other way round. THAT's IT! Hope it's a help!
Thatcham, Berkshire 001, January 2010
