Right, in order to fit the 2nd battery to my S1 Disco, i need to remove/relocate the vaccum canister on the N/S front behind the headlamp.
What is it for? and where would be best to move it to?

Does it look like this:-



Pete.

That looks like the solenoid for the EGR, i think hes talking about the sphere or bullet shaped vacuum resevoir/tank.
If so its just to store vacuum so it can be used for the heating system etc without stealing all the vacuum pressure. Doesnt matter where you put it, anywhere will be fine apart from where it will get beaten off of course. :-)

If it's a round ball type one it's for the heater flap controls (I think). I moved mine up to the bulhead when I fitted a second battery in my 200 Series Disco. The 300 series doesn't have the vacuum thingy.

HTH

Ivan

no, i may have mislead slightly, , in that it is behind the headlamp panel, where the jack sits. IIRC i have seen them on RRC's as well.
it looks like a large tennis ball.....

It's called a Vacuum tank (a ball with a pipe in and one out) and used inconjunction with the heating system up to VIN LA067123. You can position it anywhere in the engine bay.

As per Ivan above the heater flaps are controlled by vacuum.

great stuff - cheers all