Question about 1987 Ford Ranger

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Brakes apply themselves

When I barely touch the brake pedal, the pedal depresses itself and a vacuum leak sound comes from under the hood. additionally, when the pedal is depressed firmly, the engine slows and almost dies.

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  • 151 Answers

By the sound of this the brake booster is leaking fix the vacuum leak or replace the brake booster and all will be ok

Posted on Feb 17, 2012

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Posted on Jan 02, 2017

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SOURCE: 1980 ford f700 electric brake

If the vehicle is equipped with a separate hydro boost pump, it could be going bad. If the pump isn't supplying the proper pressure to the hydro booster then the electric motor will continue to run. there is also a relay beneath the hydro boost/master cylinder assembly that could be sticking. The motor is there to supply braking assist pressure when the engine powered pump is not running.

Posted on Nov 02, 2008

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SOURCE: hard to shift into park.depressing brake pedal does not release

the brake switch may be failing, causing the gears to stay in a locked position making it hard to shift into park

Posted on Dec 27, 2008

  • 24 Answers

SOURCE: For Expedition 99 150K miles

Cloged cataylatic converter. You can check this by removeing the O2 sensor before the "cats" and you WILL notice "normal operation". Granted it will be loud but it will safely get you by untill you can get to a muffler shop to replace or do what ever means necessary to "unclog" ;-) the cats, becuase on an Expedition, having 4 cats at most that might need to be replaced equals around $1500.

Posted on Feb 21, 2009

  • 149 Answers

SOURCE: 2005 Ford Escape Hissing sound

The power brake booster has a bad valve. I can't suggest where to find a new valve for it, but you can buy a rebuilt replacement. They are usually not hard to put on.

Posted on Jul 02, 2009

  • 3600 Answers

SOURCE: My 1999 Explorer's brake lights don't work every time you depress

check to see if the brake switch is loose, get on your knees press the brake pedal down and look at the brake switch on the brake arm and see if you can wiggle the switch, if you can that is your problem and is a common one for ford they use a plastic threaded switch, 90% do now days.

Posted on Nov 22, 2009

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1 Answer

How to fix brake booster " ?"

You will need to replace the booster. Unbolt the master cylinder from the front of the booster under the hood, then go inside of the cab and under the dash unhook the actuator rod from the brake pedal and remove the 4 nuts that hold the booster to the firewall. Then make sure to unplug the vacuum line from the booster under the hood and pull the master cylinder off of the booster being careful not to kink the brake lines. The booster should come right off.

Sep 03, 2014 | 1988 Ford F 150

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Rpm increases when brake is applied

Your power brake booster has a leak. With the pedal depressed sometimes you can hear the leak coming out of apply shaft area under dash.

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Why does my 2003 ford taurus idle up when i apply the brakes

There are a few obscure potential causes, but these are less likely than the most common reason: The power assist brakes are operated by a vacuum diaphragm which is provided vacuum from the engine. When the diagram inside the brake booster has a leak, when you apply the brakes it causes a vacuum leak for the engine which will raise the idle.

With the car in park, engine running, make sure that it comes and goes every time that the pedal is depressed and released. Another way to check it is to turn off the engine, wait about five seconds, then depress the brake pedal, counting how many times it can be pressed before the assist goes away (you will see a difference).

If you can press it four times or more, the leak may be elsewhere, however if it only presses once or twice (before it gets hard, and only goes halfway down), it has a leak and will need to be replaced.

Good Luck!

Apr 05, 2014 | 2003 Ford Taurus

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When I turn off my 2001 Camry I can hear what sounds like a high-pitched whistling that lasts for about 15 seconds and it appears to be coming from the brake booster.Brake fluid levels were fine and I...

It probably is from the brake booster. The booster uses engine vacuum to assist in braking. It's either a vacuum hose leaking, or possibly the diaphragm in the booster itself. Apparently, the leak is small right now and is not affecting performance (engine vacuum is sufficient to make up for the leak), but eventually the leak may become large enough to lose the assist. Check the large hose that runs from the intake manifold to the booster for any weathering/cracks, and replace it if there is any doubt. If that is not the problem, you will probably have to replace the booster.

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you have a vacuum leak from the brake booster probably down by the pedal if you can hear it inside the truck.

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Yoou most likely have a vacuum leak in the line from the booster to the intake. It could be a bad booster or check valve as well.
RPM Northwest

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this noise is caused by a defective power brake vacuum booster, (big round thing behind the master cylinder) the diaphragm is leaking vacuum.

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your power brake booster has failed, or the large vacuum line to it under the hood has come undone.

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