Bongo Fury

Having just fitted new glowplugs, I now have brocken another bit. Looks like a one way valve/diaphram or something . It is green in colour look a bit like a party popper with pipes out of both ends. One end comes from large tube coming from behind air filter then it goes in to the block of electrical switches in front of glow plugs. The one that has to be removed via two bolts when fitting plugs as in fact sheet. Doe anyone know what this bit does and where can i i get a replacement from.
Thanks
Al & Chris

I seem to recall it being a vacuum pipe, give bell hill a ring...They'll have one for sure.