1999 Cadillac Escalade sudden spongy feel in brakes

Tiny
HEAVY DUTY
  • MEMBER
  • 1999 CADILLAC ESCALADE
  • V8
  • 2WD
  • AUTOMATIC
  • 167,896 MILES
Suddenly my brakes gave out and I changed the master cylinder, bled, the brakes, but I still feel it spongy and it also makes a hissing noise from where the gas pedal is located. I also noticed that when the truck was on, it also seemed to bog down everytime the brake pedal was pressed. Can anyone help me figure this out. I don't have the cash to take it to an auto repair shop. Thx.
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Friday, August 20th, 2010 AT 1:47 PM

10 Replies

Tiny
WRENCHTECH
  • EXPERT
It sounds like you may mav a brake booster leaking vacuum when the brakes are applied.
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Friday, August 20th, 2010 AT 1:57 PM
Tiny
BDOGG0070
  • MEMBER
If the brake booster was bad or leaking then your brakes would be hard to push. Sounds like there is possibly either a leak in your brake line somewhere, air still in the system, or even a bad master cylinder. Even though you put a new one on. I personally have put new ones on and it come back to me in a couple days because the new part was faulty.
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Friday, August 20th, 2010 AT 2:08 PM
Tiny
BDOGG0070
  • MEMBER
When you bled the brakes in what order did you do so? You also have to "bench bleed" the master cylinder before putting it on the vehicle or it will not ever bleed out right at the wheels.
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+1
Friday, August 20th, 2010 AT 2:10 PM
Tiny
WRENCHTECH
  • EXPERT
No, the brakes would not necessarily be hard to push. You have have a leaky booster that still operates normally. That is where the hissing is coming from when stepping on the brake.
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Friday, August 20th, 2010 AT 2:17 PM
Tiny
BDOGG0070
  • MEMBER
If it is constant hissing it could be a vacuum leak at the power booster but if the master cylinder was not bench bled then you will hear a short hiss as you are pushing the brake pedal due to the air trapped in the master cylinder
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Friday, August 20th, 2010 AT 2:28 PM
Tiny
WRENCHTECH
  • EXPERT
OK, that's just ridiculous. I've been doing this 40 years and that is the stupidest statement I ever heard.
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Friday, August 20th, 2010 AT 2:33 PM
Tiny
BDOGG0070
  • MEMBER
Well now, just because you have not come across that problem before does not meen that it does not exist, I personally have and successfully diagnosed this sort of problem before in MY shop. Just because someone does not agree with your OPINION does not make it ridiculous at all. It just gives the person a wider spectrum to look at to what the problem really is.
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Friday, August 20th, 2010 AT 2:38 PM
Tiny
WRENCHTECH
  • EXPERT
To make the statement that you can hear air flowing in a master cylinder is beyond ridiculous.
I was trying to help the poster here but your on your own.
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Friday, August 20th, 2010 AT 2:42 PM
Tiny
BDOGG0070
  • MEMBER
I as well was trying to help this poster out but I HAVE been able to hear air in the master cylinder if it has not been bench bled. Maybe your just so old your hearing is fading!
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Friday, August 20th, 2010 AT 2:51 PM
Tiny
BDOGG0070
  • MEMBER
HeavyDuty I apologize for some of what is going on with your post but you should check it all. What he said and I as well. If you have someone stand with their ear to the power booster you should be able to hear where the sound is coming from. Hop one of us has helped you out. God Blless and have a nice day!
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Friday, August 20th, 2010 AT 3:16 PM

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