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sqhertz
06-23-2009, 06:25 PM
since i did the water pump on my 96 blazer , the brakes have not been working. the pedal is harder to press and makes a 'ssssss' sound when pressed. even just putting it in gear with the brake pressed all the way , the truck will still move some.
im trying to sell it so i dont want whoever buys it to kill themselves right around the corner.
my buddy came over yesterday and bled them , but it still feels the same as it did. also , the rpms drop when the brake is pressed while in gear with the AC on. :confused:


halp?

Einzee
06-24-2009, 06:41 AM
Sounds like a vacuum power booster. Its that big round thing that your brake master cylinder is attached to.
I'd double check all of the hose connections under the hood and pay particular attn to the large one that connects to the booster. Consult the vacuum diagram sticker that is usually under the hood on GM's.
An easy way to test the booster is to press the brake pedal down several times while the engine is not running. Keep pressure on the pedal as you start the engine. The pedal should drop down 1-3 inches when the engine starts. If all vacuum connections are correct and the pedal does not drop then your booster is most likely defective.

sqhertz
06-24-2009, 10:05 AM
Sounds like a vacuum power booster. Its that big round thing that your brake master cylinder is attached to.
I'd double check all of the hose connections under the hood and pay particular attn to the large one that connects to the booster. Consult the vacuum diagram sticker that is usually under the hood on GM's.
An easy way to test the booster is to press the brake pedal down several times while the engine is not running. Keep pressure on the pedal as you start the engine. The pedal should drop down 1-3 inches when the engine starts. If all vacuum connections are correct and the pedal does not drop then your booster is most likely defective.



thanks , ill check that out.

tdg
06-25-2009, 11:17 AM
Was the reservoir low when bleeding them? If so it could be an external leak somewhere bleeding off pressure. If not it could also be the master cylinder that has an internal leak causing the pressure to bleed back instead of being forced to the brakes.

Proximity
06-25-2009, 11:22 AM
Do you see any brake fluid leak?