vacuum rubber hoses for heat control

[harry3]

with factory heat and air cond the system uses many vacuum rubber hoses to operate things, the heater water valve is operated by vacuum working some type of motor that adjusts it, its all up under the dash near the steering column
these vacuum hoses pull off easlly so be careful if feeling around under the dash, the hose had fallen off my water valve control so no heat, fortunately all came good whan I pushed it back on after 20 years, I expect the hoses have lost some elasticity

the main vacuum tank is under the front bumper bar

if theres a leak in the vacuum system would this make the engine run lean?

[vlct400]

i think it would make it run rich cause i had the same thing but for the cruise control and my mechanic said it would run rich