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Old 10-29-2004, 10:24 AM
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Re: F250 soft brakes

This is NORMAL. If the vehicle stops well (pedal does NOT sink until the vahicle is fully stopped), there is nothing wrong.

The cause is the vacuum pump system. While you drive, the vacuum pump applies a vacuum to the brake booster, but there is NO reservoir of vacuum, and the pump's capacity is not all that great. When you apply the brakes, you lose some vacuum (and the engine is now turning near idle speeds). As you stop, you modulate the pedal very slightly and this uses a little more vacuum. While you are stopped, the vacuum pump keeps pumping, which INCREASES the vacuum pressure on the brake booster, and "sucks" your foot to the floor. If it stops well, don't worry about it.

Newer units use a hydraulic pump for boost, eliminating this concern.
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