Mysterious tin can in the right front wheel well

[Yood]

Had a friend asking me today about a tin can instaled in the front right wheelwell of his newly aquired 68 coupe.
I took a look and found the contraption to have two hose type connections in the engine compartment side. Prob'ly indtalled in the wheelwell to save space. It seats next to some A/C hoses and a more modern looking canister is installed in the engine compartment.
Attached are a couple of pix.
Who's in the know?
Can you shed some light on it so I can give my friend a good explanation?
Thnx
Yood

 

[Midlife]

Vacuum canister for A/C system.

 

[AzPete]

Really it was a way to hid your drugs. Light it and inhale thru the hoses..... :amaz

Mid is correct. That was there so you always had vacuum available for the A/C to function. Hard acceleration could cause the vac. to disappear and doors and valves would change quickly.

 

[daveSanborn]

LOL.... what's really weird is that if you remove that can and sit it on the workbench next a quart sized can of B&M baked beans... I swear that Ford made those vacuum cannisters from empty cans found out behind the plant's cafeteria.

 

[PJ Moran]

Like the others said, it's your vaccuum reservoir for the factory AC system. They rust and develop leaks and quit holding vacuum. Up until just a few years ago, they were not reproduced, so folks had to resort to retrofitting other vacuum cans. I had to do that on mine until the repops came out.

There is a check valve in that can - it's not just a dumb can. If you don't plumb the right kind of check valve into your retrofitted system, it still won't work right.

The thing to do is spring for a new (correct) can and ditch that other stuff. They're not cheap, but...