why is brake petal hard?

[yourkiddin]

guys i have a 94 chevy silverado. its got air noice coming from around the brake petal area when pressing it. but instead of it being soft and going to the floor its hard and will barely stop me. i was thinking a stuck caliper but theres no scraping or rubbing noice. any thoughts appreciated. i know some one will have the anwser.

 

[rbh]

Re: why is brake petal hard?

Vacum diaphram thing's toast????

 

[yourkiddin]

Re: why is brake petal hard?

im sorry could you be more specific. im not familiar with that. where is it located? i was doing some research and it pointed to the brake booster . is that what you are calling the vacuum diaphram?

 

[DECK SWABBER 58]

Re: why is brake petal hard?

Yep, you need to replace your vacumn booster.
(The big round thing right behind the master cylinder)

 

[windsors03cobra]

Re: why is brake petal hard?

My vacuum assist power brake unit fail the same way on my 99 Grand Cherokee.
My power brakes still mostly worked and the hissing stopped while the brakes were fully depressed. What an annoying noise, and loud OMG.

I replaced mine with a junkyard piece for $50 I think it was. Better than $300 from some aftermarket reman.

 

[slia67]

Re: why is brake petal hard?

Start your car let it run for a minute or so. Shut the engine off. Press the brake pedal several times until it becomes hard (you're bleeding off the vacuum in the brake booster at this point), it may take 6-8 pumps on the brakes. Once it's hard, keep your foot on the brake pedal and start the engine. You should feel the brake pedal drop as you start it. If you don't feel it drop you either have a bad brake booster as everyone has mentioned, or you have a vacuum leak to the brake booster.

Before replacing the booster, check to see if you have hole in the vacuum hose going to the booster. Make sure the line has not come loose. But, more than likely with the noise coming from the brake pedal area when you apply the brakes you are going to need a booster assembly.

Oh yeah, check to see if you have paint bubbling on the bottom side of the booster where the master cylinder mounts to it. If so, you will either need to rebuild your master cylinder or get a new one. If your master cylinder is leaking into your booster it can cause premature failure of the vacuum diaphram.

Let us know.

 

[slia67]

Re: why is brake petal hard?

im sorry could you be more specific. im not familiar with that. where is it located? i was doing some research and it pointed to the brake booster . is that what you are calling the vacuum diaphram?

The vacuum diaphram is inside the brake booster (the big round black thing that your master cylinder is mounted to).

 

[BuzzStPoint]

Re: why is brake petal hard?

There is a hose coming from the booster to the engine. Make sure that hose is connected or not cracked.

Normally if the hose is disconnected you'll have engine idling issues.
If you can get a hold of a vacuum hand pump you can put vacuum on the booster and check to see if the booster is bad or not.

If it's bad, I would check the local salvage yards. .