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Old 09-24-2017, 02:52 PM   #1
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Need Brake diagnosis

Hello!

I need some suggestions for brake diagnosis...Here's the symptoms.

Brake pedal is super stiff when car is off, and stays that way when car starts. Front brakes are locked.

Others have suggested maybe the front calipers are shot. I took them off, pushed the pistons back in, bled the front brakes, and still same issue. I figured if the calipers were stuck, then I might not be able to compress them back.

From what I've found, it sounds like maybe the hydroboost is bad??? What do yall think. I just don't want to buy part after part.

thank you in advance
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Old 09-24-2017, 10:51 PM   #2
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After doing some research, I am going to purchase new hoses and calipers for starters---they are factory original from 03, so figured probably needs replacing.
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Old 09-25-2017, 05:49 AM   #3
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Have you tested thr vacuum of your break booster? Just before you turn off the engine, push down on the brake pedal and hold it for 5-10 seconds... Turn the engine off and continue holding your foot on the pedal for another 30-40 seconds. If the brake pedal stays where it is, then the brake booster can hold a vacuum.
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Old 09-25-2017, 12:46 PM   #4
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Thank you. With the car jacked up, the back wheels spin, and the front wheels are locked. The back wheels will brake, and then release as designed, but the fronts are stuck, so i THINK the booster is working properly since the back brakes will still work IDK....

With the car off, the brake pedal is super stiff, and when the car turns on, the pedal is still stiff. pedal overall only goes down about 1/2".

What do you think??
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Old 09-25-2017, 04:11 PM   #5
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Power brakes will always be stiff when the car is not running. Same thing with power steering.

Are the front wheels locked without the pedal being pressed, or are they rubbing on the pads and hard to turn?

Most of the braking power comes from the front brakes. They do the majority of the work. The rear brakes are always lighter. If the rear had the same power as the front the car would spin under hard braking, essentially unintentional drifting.
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Old 09-25-2017, 08:47 PM   #6
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Quote:
Originally Posted by Smotpoker15 View Post
Have you tested thr vacuum of your break booster? Just before you turn off the engine, push down on the brake pedal and hold it for 5-10 seconds... Turn the engine off and continue holding your foot on the pedal for another 30-40 seconds. If the brake pedal stays where it is, then the brake booster can hold a vacuum.
The power assist for the braking system is supplied by the hydro-boost. Not vacuum.
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Old 09-25-2017, 08:49 PM   #7
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After doing some research, I am going to purchase new hoses and calipers for starters---they are factory original from 03, so figured probably needs replacing.
This is where I would start.
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Old 09-25-2017, 09:11 PM   #8
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The power assist for the braking system is supplied by the hydro-boost. Not vacuum.
test will still work for psi fluctuations...you can also press brake pedal and hold...then start the engine. the pedal will fall slightly and then hold. Less pressure will be needed to hold the pedal in this position... also check for leaks ect.. but for a 14 year old car calipars would also be a wise place to start regardless
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Old 09-26-2017, 09:57 AM   #9
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Thank you all...I have been searching through posts and happy with yall's responses. the calipers and lines will be here in a couple days.
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Old 09-26-2017, 12:07 PM   #10
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Does opening the bleeder valve on the caliper release it? I wonder if the MC is not releasing pressure like it should.
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Old 10-03-2017, 08:48 AM   #11
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thank you, replaced lines and calipers, and all is good!
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Old 10-03-2017, 08:50 AM   #12
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new rotors too
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Old 10-03-2017, 12:08 PM   #13
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Thanks for the heads up, glad you got it fixed.
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