More vacuum-assisted brake pedal applications should the engine not be running. No more braking assist than usual, just more assisted pedal presses. The extra tank was often paired with a factory dashboard vacuum gauge in the instrument cluster. On the F-series, that gauge would be on the left side of the dash.

 

yes i have the vacuum gauge as well on left side .
very interesting features with these older trucks

 

Going to need a miracle !! One of my shoe adjusters was completely frozen on the bottom passenger side .. i spent 2 days trying to free it with no luck and thought i could pull the bracket assembly off the backer but they were either frozen or riveted from factory not to come apart from the backer .
would anyone have a backing plate with two working adjuster mechanism?? I will attach a photo of mine .

 

That's going to be tough, because they are handed (L/R) and specific to the 7" shoe width.