I heard a loud pop, and now the brake pedal has no resistance. There are no leaks in the system. I tried a master cylinder and bleeding the brakes. Still the pedal goes down easy and comes up slow. There is no vac booster on this system. I'm not sure how it works. The vehicle is a 2003 Chevy Express van.

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    Does it have hydro boost? Power steering lines running into device that the master cylinder bolts to? Also what size engine and weight rating (1/2, 3/4, 1 ton) Oct 22, 2014 at 16:23
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    Also is it equipped with ABS if so 2 or 4 wheel? Oct 22, 2014 at 16:25
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    The lack of punctuation, etc., made your question hard to read and understand. I have submitted an edit to fix it. Please check to make sure I have not accidentally changed something important. Oct 22, 2014 at 18:24
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    How did you verify that there are no leaks? Oct 22, 2014 at 18:25

1 Answer 1


The point you make that there are 'no leaks' points to an internal system leak. The most common fault that you will find in this description is a brake hose fracture. The flexible brake hoses are made of an internal hose surrounded by an external hose. If the internal hose fractures, it allows the brake fluid to go between the inner and outer hoses when you press the brake. When you release the brake, the fluid returns into the inner hose - hence no extenal leak. Check each flexible hose individually with someone pumping the brake. Any 'ballooning' of any hose under pressure shows it as defective and must be replaced.

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