05 Chevy Malibu Brake Prob.
 

Ok guys, my mom took her car to wal mart to get the oil changed yesterday. Her brakes were fine when she dropped it off but when she picked it back up her brake pedal was VERY hard and wal mart swore up and down they didn't touch her brake system.

The best way to describe whats happening is this....if you were to pump the brake pedal up with the vehicle off you'd get about 2" of pedal travel and itd be very hard to push, when you started the vehicle the pedal would drop and get soft and normal again. Well, my moms car brake pedal feels like you pumped up the pedal with the vehicle off but its actually running. It is very hard to push when shes driving and takes quite a bit longer to stop the car. Id like to get this fixed ASAP for her.

Where could i start to check the brakes and the possible cause of this. Thanks guys!

Check the Vaccum hose coming off of the brake booster ( big round black thing between the fire wall and the master cylinder) see if they knocked the line off somehow.

Make sure they did not overfill it. I am not sure what all they check at those places, but I could see a high school kid filling up the brake fluid thinking he was doing a good thing.

would over filling the resevoir create the same issue as having no vacuum, to the booster?

Nope!

I agree, it sounds like they knocked off the vacuum hose to the booster or they could of broken the valve on the booster that hose connects to.

well...i checked the hose from the intake to the booster and its intact at both ends....its soft and doesnt feel cracked/sliced anywhere...what else could i check

ok......update..

I pulled the coolant reservoir off and checked the entire vacuum hose between the brake booster and the upper intake plenum. There is NO VACUUM at idle coming from the brake booster or the intake.

My mom also told me they had done a fuel system flush on the car , but i dont see where that would effect the vacuum system at all. Maybe im missing something? If anyone has any more insight on this it would be great. Thanks!

The fuel system cleaning wal-mart does is really an induction cleaning service..they disconnect a vacuum hose and let an induction system cleaner drip into the intake. It really does not clean the fuel system at all and "may" remove a little carbon in the intake if it is done correctly. Double check all the vacuum sources and make sure they have the proper hose attached. Does the car idle at normal speed or are the rpms higher than normal?

i figured it out....the brake booster check valve was bad....when i pulled the hose directly off the intake the engine died immediately.

What would wal mart have done though to make that check valve fail....