Dear Thirtianese,
Was testing my check valve/brake booster yesterday, and I noticed that I could decrease the idle from around 750 rpms down to nearly 500 rpms by rapidly pumping the brake pedal. After pumping the idle would remain low. Brakes are not difficult to push at all, so it's at least not leaking vacuum on the constant vacuum side of the booster. Is this normal? Seems very strange to me.
Thinking about how a brake booster works, I don't quite understand this, unless -- maybe? -- there were a slight leak on the rear side of the booster that goes from vacuum to atmospheric pressure when the brakes are applied?
The check valve basically doesn't do anything at all so long and the engine is running and there's vacuum from in I.M., right?
She holds vacuum when the engine stops running, and applies vacuum to booster no problem (she passes all the Bentley tests).
Just curious why I can dial in my goddamned idle with my brake booster haha.
Any ideas?
Was testing my check valve/brake booster yesterday, and I noticed that I could decrease the idle from around 750 rpms down to nearly 500 rpms by rapidly pumping the brake pedal. After pumping the idle would remain low. Brakes are not difficult to push at all, so it's at least not leaking vacuum on the constant vacuum side of the booster. Is this normal? Seems very strange to me.
Thinking about how a brake booster works, I don't quite understand this, unless -- maybe? -- there were a slight leak on the rear side of the booster that goes from vacuum to atmospheric pressure when the brakes are applied?
The check valve basically doesn't do anything at all so long and the engine is running and there's vacuum from in I.M., right?
She holds vacuum when the engine stops running, and applies vacuum to booster no problem (she passes all the Bentley tests).
Just curious why I can dial in my goddamned idle with my brake booster haha.
Any ideas?
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