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Soft brake pedal when car is on

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Old 04-09-2016, 09:41 PM
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Soft brake pedal when car is on

I have a 2007 HHR LS sitck shift. I jusy spent the day replacing brake,rotors,calipers and the rear drums. After hooking everything up and bleeding the lines. The pedal will still go right to the floor. We bleed the master cylinder and it help but its still not right. The pressure builds up great with the engine off but the system looses pressure as soon as i turn the car on. Any ideas?
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Old 04-09-2016, 09:46 PM
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Check the vacuum hose and check valve to the brake booster.
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Old 04-09-2016, 09:47 PM
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Originally Posted by donbrew
Check the vacuum hose and check valve to the brake booster.
Im gunna check those tomorow called it quits for the night any possibility it could be a bad master cylinder?
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Old 04-10-2016, 03:09 AM
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I'm no mechanic, but I hung around my uncle's shop for 25 years (he was a brake specialist) and my first thought went to the master cylinder. If the pedal was going to the floor before the brake job, sounds like you may have just replaced a lot of parts unnecessarily.
Even with the engine off you'll still be able to hold down on that brake pedal and it will sink slowly to the floor (if the m/c is bad).


Welcome to the site - lots of great information here and lots of great guys who are happy to help!
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Old 04-10-2016, 07:19 AM
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Originally Posted by Clob285
Im gunna check those tomorow called it quits for the night any possibility it could be a bad master cylinder?
Yes. Be looking for brake fluid where it shouldn't be.
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Old 04-10-2016, 08:00 AM
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Sounds like there is still air in the system. Also, check for any leaks as Donbrew suggested.

You may need to use a pressure bleeder.
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Old 04-10-2016, 09:01 AM
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Welcome to the site, sounds like them aster cylinder has been over pumped, and it sucked back air into the system, double check all the hoses , lines and fittings, the rear wheel cylinders and the front calipers!
Also the seal at the booster side of the master cylinder, if it's wet your gonna have to replace it
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Old 04-10-2016, 01:07 PM
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Originally Posted by Clob285
The pressure builds up great with the engine off but the system looses pressure as soon as i turn the car on. Any ideas?
Builds how? If you have to pump the pedal there is still air in the lines. Also if rear drums are they adjusted properly? This can also affect pedal feel.
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Old 04-10-2016, 07:52 PM
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Thanks guys turns out the location of the bleeder screw on the calipers was the issue. Air was getting trapped in the calipers got those bleed all good thanks again.
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Old 04-10-2016, 09:30 PM
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So you flipped the calipers left for right? Now the bleeder screws are on the high side!
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