No brakes in the morning. It will definitely wake you up more than coffee.

[jamesd]

HO Ho-So I am not losing my mind after all. I have a 2004 aveo 5 speed with same problem. At random times, I go to stop the car and the pedal is rock hard. Feels exactly like the master vac. has failed. Car is running smoothly, it's not like there is a huge vacuum leak. After a couple minutes, brakes work fine. Usually happens in the morning, just a few minutes into my drive to work. This has happened 6 ~ 10 times in past year. I am ready for it now, I am ready to stand on the brake pedal if need be. Will not let my wife or kids drive the car because of this. So what gives?

I'm sure you may have solved your issue by now but for me it was definitely the brake booster hose. The check valve built inside the hose would get stuck! Thus what you are feeling is a sporadic hardness of the pedal. I verified this using a hand vacuum pump. Since the replacement of the $5 brake booster hose, no more issues. Thanks for WyrTwister for pointing me to the right direction.

Sent from my SAMSUNG-SM-N920A using Tapatalk

[WyrTwister]

My pleasure .

God bless
Wyr

[Topher79]

Sorry for upping an old topic, but....

I just joined this forum to say thank you for James and Wyr for figuring this out... I don't even know if either of you even post here any more.

I have a 2005 Aveo.

For the past couple weeks, I was braking hard the first and maybe second time I had to brake in the morning. Then last week, it didn't stop braking hard.

I googled my symptoms and found out that it was maybe a good chance that it was a check valve issue... but I couldn't find what looked like a common-looking check valve. I think Autozone even had a normal looking check valve listed on their website for sale.

But thanks to this topic.. I found out that the valve was built into the booster hose.. Nobody local had a new one in stock, so I ordered a new one off Amazon, got it the next day, put it on... and whammo... awesome braking again!..

[WyrTwister]

Congratulation on a good repair !

Wyr
God bless

[Jmcr749]

My daughters car is having this same problem. Can anyone help me find the break booster hose on Amazon? It’s a 2005 Chevy Aveo LT. I can’t seem to locate it. Thanks so much! This thread has been incredibly helpful.