Quote:
Originally Posted by Diseasel300
WRONG!!!!!!!
The vacuum assist is to help PUSH the pedal down, not pull it back up.
Without the vacuum assist, it is hard to get sufficient brake pressure to diagnose a master cylinder unless it is extremely worn. When the vacuum builds to operate the booster, it's MUCH easier to push the pedal down. Since you have more force available to push the pedal, smaller leaks and faults will show up.
A sinking pedal is a sign of a leak or a failing master cylinder. If you find no leaks anywhere (check caliper seals, hoses, ABS pump, etc) suspect the master cylinder.
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Try it, it is a common test.
Although what I have read is you press the pedal down a 1/4-1/2 inch with the minimum pressure on the pedan and when you start the Engine and vaccuum gets to the Power Brake Booster the Pedal pushes back up.
The reason it does that is because when you forst start and Vacuum gets to the Booster the internal valves try to center the innards of the Booster.
08-09-2017, 01:55 PM
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