Hard brake pedal

Tiny
RPJ
  • MEMBER
  • 2008 CHEVROLET AVEO
  • 1.6L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 144,000 MILES
Hello,

Lately in the morning I have noticed when I start driving and press the brake pedal, it sometimes is stiff. I have to pump it once or twice to get it to go down.

Is this a master cylinder/brake booster starting to fail?

Only happens after sitting overnight in cooler weather. It does not happen any other time.

Thanks for your help, Roosevelt.
Wednesday, May 12th, 2021 AT 2:19 PM

20 Replies

Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
Hello, I'm Harry. Given your description, I would suspect the brake booster is failing. But first I'd check the vacuum lines for leaks. Especially the one going to the booster. Also take a good look at that check valve (mounted to the booster, vacuum hose one the other side of it). If it's allowing any blowback then it could easily be your issue. Replacing it is cheap and should be done even if you need a new booster too. I'm attaching instructions on the check valve to this post. I'll do another post shortly regarding removing and replacing the booster.
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Wednesday, May 12th, 2021 AT 3:14 PM
Tiny
HARRY P
  • MECHANIC
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And here's the booster procedure. In my experience, while I haven't done the job on your specific vehicle, I suggest removing the driver's seat. It'll be a little more bearable.
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Wednesday, May 12th, 2021 AT 3:33 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
Thank you very much for the information. My mechanic could not duplicate the problem, so I will let him know what I think should be done. Thanks again, Roosevelt.
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Wednesday, May 12th, 2021 AT 5:42 PM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
If he couldn't duplicate it, then my money is on that check valve. It's sticking occasionally. Eventually it'll get worse. I'd order one off of Amazon or Rockauto while it's not a pressing issue and either go ahead with replacement or at least have it on the shelf and ready. It'll be cheaper that way.
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Wednesday, May 12th, 2021 AT 7:54 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
Thanks, I'll do that! I appreciate your help. Roosevelt.
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Wednesday, May 12th, 2021 AT 8:21 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

I noticed we haven't heard from you for a few days. Did the check valve eliminate the problems you were having? We're interested in knowing.

Joe
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Saturday, May 15th, 2021 AT 11:20 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
Hello, I haven't had the car serviced yet, I'm planning on doing it this week. It seems to be rather difficult finding the part for this vehicle. Thanks for the follow up, I will let you know what happens.
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Sunday, May 16th, 2021 AT 6:08 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

No problem whatsoever. We like to know if progress is made or if additional help is needed. We'll wait until we hear from you.

Take care,

Joe
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Sunday, May 16th, 2021 AT 6:23 PM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
Hey again. I did some poking around and found the check valve. Here it is on Amazon. AutoZone has a comparable price and should have it on the shelf. It's Dorman brand part #80189.

https://www.amazon.com/dp/B003GBIJ5I/ref=cm_sw_r_cp_apa_glt_fabc_RPTVR87DPW1054SMPZEC

Hope that helps you.
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Sunday, May 16th, 2021 AT 6:46 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
Wow, I really appreciate you finding that! You guys are the best. I will order it tomorrow, thanks so much! Roosevelt.
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Sunday, May 16th, 2021 AT 8:24 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
No problem. Let us know how things turn out for you.

Joe
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Monday, May 17th, 2021 AT 8:25 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
I sure will, thank you!
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Tuesday, May 18th, 2021 AT 6:40 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
I ordered the part today, will have in shortly. Thanks.
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Tuesday, May 18th, 2021 AT 6:46 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
  • 2008 CHEVROLET AVEO
  • 1.6L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 145,000 MILES
Hello,

On cool mornings when I began to drive, the brake pedal is hard and won't go down. I have to pump it to get brakes. Only happens in the A.M. Could be brake booster?

I asked about this previously and the mechanic could not duplicate the problem. One of the mechanics here was very helpful to recommend changing the power brake check valve. I have it, not installed yet.

Any other suggestions? I appreciate your help. Roosevelt.
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Monday, October 18th, 2021 AT 12:05 PM (Merged)
Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
Hello,

Hard brake pedal typically means a vacuum issue for the brake booster. It could due to a sticking check valve for the booster, especially when it's cold.
So yes, change the check valve and also make sure the hose does not have any cracks or leaks.

Keep in mind that this issue could also be due to an internal malfunction of the brake booster.

Let me know how it turns out.
Thank you.
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Monday, October 18th, 2021 AT 12:05 PM (Merged)
Tiny
RPJ
  • MEMBER
  • 85 POSTS
Thank you very much for your reply. I'll do that and let you know. Roosevelt.
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Monday, October 18th, 2021 AT 12:05 PM (Merged)
Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
That sounds good.
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Monday, October 18th, 2021 AT 12:05 PM (Merged)
Tiny
RPJ
  • MEMBER
  • 85 POSTS
Hello, just wanted you to know it was the Brake Booster Check valve that was the problem on the vehicle. After keeping the vehicle overnight, my mechanic was able to duplicate the problem and replaced the part.

Thank you very much for your help on this repair.

Roosevelt.
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Wednesday, October 27th, 2021 AT 5:28 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

Thank you for the update. I know it will help others in the future.

Take care of yourself and feel free to come back anytime in the future.

Joe
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Wednesday, October 27th, 2021 AT 5:40 PM
Tiny
RPJ
  • MEMBER
  • 85 POSTS
Thank you!
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Wednesday, October 27th, 2021 AT 5:46 PM

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