Brake question....

[carcrazyguy]

I went to look at a 70 Dart yesterday and I have a question reguarding the brakes. First the car has been switched to disc brakes from a 74 Duster. The pedal felt fine but you could hear a whistle or howl I should say. I thought it could possibly be a vacuum leak but the noise went away if you just rested your foot on the brake pedal. Would that be a vacuum leak? Anyway to test the booster to see if it is an internal leak??

 

[GoodysGotaCuda]

Here are the methods for testing a brake booster for holding vacuum.

1) Engine off, depress the pedal until it is hard (no power assist). Hold that hard pedal down, start the engine. Pedal should continue further down with engine vacuum.

2)Turn the engine off. Power assist should remain at the brake pedal and not leak out. As in, turn the engine off, come back an hour later, you should still not have a 'hard' pedal.