can some on identify this ??

[C30trailerspecial]

Can some one identify this and what it does please


ok the truck is a canada import right hand drive, body tag says 1981 into Australia by GM-H (general motors Holden) c30, 350, truck 4 speed, dually, lwb

this cannister looking thing is mounted on the right front inner gaurd, it has a brake line coming from the rear of the master cylinder into the side of it and exiting the other side of it Im asuming going off to the front brakes. at the back of the cannister thingy is a cable going off to the dash, the cable is hand operated like say... a choke cable.

it has two vac hoses one (the one with red tape) goes off to the back of the truck and lopes around up to the front left inner gaurd to some kind of valve looking thing on the left inner gaurd, the other vac hose goes across the radiator to what looks like a vac tank on the other left inner gaurd. this same vac tank has a hose coming from the intake manifold to provide the vacume.

hers a pic of the vac tank


now... I cant think why it would have anything to do with the brakes because the brakes are fuild boosted from the power steer pump


the brakes in the truck work flawless, but the cannister thingy is leaking brake fluid..

what is it and whats it for???