Re: 54 Patty vacuum lines

Posted by Owen_Dyneto On 2015/3/13 11:46:11

You are asking about 3 different systems. In a nutshell and over-simplified...

The power brake booster operates on engine vacuum. The system starts at the intake manifold as a source of vacuum, and is also equipped with a check valve so that if the engine stalls, you have enough vacuum stored in the reserve tank for 1 or more power applications.

The vacuum line to the distributor from the carburetor is for the vacuum advance mechanism which alters ignition timing based on manifold vacuum. For example, under periods of hard acceleration the manifold vacuum drops very significantly and the vacuum mechanism on the distributor makes an appropriate adjustment to the timing.

The vacuum wipers will ordinarily operate on the vacuum within the intake manifold, that is, it draws air from the wiper motor into the intake manifold. When under hard acceleration, the intake manifold vacuum will drop to where it isn't sufficient to operate the wipers and in that situation the vacuum pump which is part of the fuel pump will provide the vacuum for the wipers.

In the case of the wipers and power brakes, any trivial amount of "air" expelled into the intake manifold mixes with air from the air filter to provide the air/fuel mixture needed for combustion.