Vaccuum Booster

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Jul 1, 2011 | 12:57 PM

bradleydm

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Joined: Apr 2011

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From: Iowa

Vaccuum Booster

The brakes on my 94 7.3 Turbo idi are soft and the pedal almost goes half way to stop. How do you know if it is the vaccuum pump, vaccuum booster or master cylinder that's causing the problem. Could it also be badley worn pads? Thanks for the help.

Jul 1, 2011 | 01:07 PM

Lazy K

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It is not the vacuum pump or the booster that is causing a low pedal.
The first thing you need to do is check that the rear brake shoes are good and properly adjusted up.

Jul 1, 2011 | 06:39 PM

oreocreaming

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Joined: Jan 2010

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From: Elk City, OK

go to autozone and rent a vacuum tester OR just buy one. they are cheap enough. hook it up and see what kinda pressure your pulling. its usually the cause. when you switch to vent on your blower fan does it ever go back to defrost on its own? if so, then its the pump for sure.

Jul 1, 2011 | 07:44 PM

kenpobuck

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Joined: Mar 2006

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From: Sand GAp, KY

As LazyK stated, low vac will not cause a soft pedal. It will make the pedal really hard to push. Soft pedal is cuase by many things, some of which are... bypassing master cyclinder, worn pads/shoes, improper adjustment of rear shoes, and possibly bad hoses at the front calipers or the rearend. The hoses will swell under the fluid pressure and possibly burst.

Jul 2, 2011 | 11:27 PM

Fatcatpaddy

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From: Napa CA.

How much vacuum pressure should there be?

Jul 3, 2011 | 04:00 AM

Lazy K

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Should be 18in at least.

Jul 5, 2011 | 09:43 AM

'94IDITurbo7.3

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Joined: Jul 2011

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I have replace every single brake component on my truck except vac. pump and booster and my pedal is still soft. my vac. pump pulls 25 inch lbs @ idle.