2022 GT Line brake pedal on cold start

[daveyz]

Hello, this is my first post so hopefully this is the right place. Over the past year or so, the brake pedal is hard to depress on cold starts. More recently, it gets this way when the car is not sitting overnight, but for only a few hours. Add to that, in the past month or two, there is a noise upon startup that sounds like someone is letting air out of a balloon and last for maybe 5 seconds. It was at the dealer recently and their master mechanic said that's normal and just what turbo charged engines do. I know this hasn't been there since day 1, so i really think something is up. Google says it may be a vacuum leak but the dealer didn't see anything. Before I take it another dealer, thought i would put it out here and see if this is normal or if something needs to be checked out. Thanks all

 

[Snicklefritz]

We don't have the noise, but our 2.0L engine Stinger often has a noticeably stiff brake pedal on startup. This has never occurred with the 3.3L engine Stinger. When it was still under full warranty, the 2.0L failed to start three times in less than a year and we took it in for diagnostic. The dealer did a "reflash" of the starting system. This was nearly two years ago and no trouble starting since, but the stiff brake pedal persists. It no doubt has some cause. But unless the car develops starting issues, it won't be worth bothering to take it in.

 

[Snowwhite]

it's the brake booster. mine was replaced and the problem went away. the hissing noise you hear is the vacuum pump trying to get some vacuum back into the system while the car is idling.

 

[Alpinesting]

Expansion and contraction of a seal or grommet in the brake booster could cause this. Best to replace it.

 

[daveyz]

Than you for the input. I talked to the service advisor today and they are going to schedule me to come back in and have it looked at.