well as it says when the bus has been driven a short distance when you stop and start to walk away you hear a great big bang like the fuel tank has been sucked in and than expands any one have any ideas:jesus

are the breathers blocked???

Anyone dont like u, couldve added some baking soda or chlorine to tank.:P

There is nothing much down there breathers and sender reciever. Thats about it.
What is frequency of banging (expansion and sudden contraction)?
Hot days?
Got any fuel in there?
Any other symptoms, poor accel; anything else?
Have u checked the fuel pump? Is it maybe blocked and causing a vacuum?

its the t3 gremlins:alien

yep t3 has fuel and will happen at anytime relly spooke

maybe a gerbal?

Any pressure release from tank filler cap when removed?
Is the charcoal filter valve working, it's a minor but worth a look.
Also There is a Pressure regulator on the passenger side of tank, it serves to normalise return pressure from the fuel injectors at shut down and fuel overload. Sound Familiar?

I have a petrol can for the mower that does the same thing.

[ Edited on 22-5-2007 by Iwish4aSynchro ]

the tank vents are blocked

thanks it's nice to have a place to start

So whats progress??

looks like a collapsed tube or old age has made it unservicable

all fixed turned out to be the charcole cahister making the tank bang thanks iwish

i th't ya had a tiger in yer tank....

Not just a pretty face
Tis all good.