weird brake pedal

[geeturbo]

Has anyone experienced this? Sitting at light, foot on the brake, after a minute or so the pedal will drop just a bit, maybe a inch or so, with sometimes a bit of an engine shutter. It may be my imagination, but it also seems like my brakes feel a little grabby when it happens too. It dosen't happen all the time and my dealer can't seem to make it happen. Go figure lol. It started about 3-4 months after i bought the car so I wouldnt think it was normal. Any one else experience this? Other than that I love my little "Turbo" !

2012 Sonic hatch 1.8 5 speed manual
(I know hes not a turbo, its just his name)

 

[GunBlade]

I have this happen every so often as well your not crazy. Mainly like you said while idle at a stop or slowly creeping to a stop. Never seen this happen in any other car I have driven. I have had no problems with my brakes at all though so I don't know what to call it.

 

[geeturbo]

Thanks. I'm happy just knowing I'm not entirely crazy! Lol

 

[Chevrolet Customer Care]

Has anyone experienced this? Sitting at light, foot on the brake, after a minute or so the pedal will drop just a bit, maybe a inch or so, with sometimes a bit of an engine shutter. It may be my imagination, but it also seems like my brakes feel a little grabby when it happens too. It dosen't happen all the time and my dealer can't seem to make it happen. Go figure lol. It started about 3-4 months after i bought the car so I wouldnt think it was normal. Any one else experience this? Other than that I love my little "Turbo" !

2012 Sonic hatch 1.8 5 speed manual
(I know hes not a turbo, its just his name)

Hello geeturbo,

Glad you are loving your Sonic Turbo. If this is a concern you would like to discuss with your dealer, please let us know. We are more than happy to assist during that process. We can be contacted via private message. Be sure to include your full contact information, VIN and current mileage in the message.

Sincerely,

Laura M. (assisting Jackie)
Chevrolet Customer Care

 

[ss2000slp]

Is the a/c or defroster on when this happens? When the compressor kicks on in these cars it will cause the engine rpms to change, and could cause a slight drop in the brake pedal (an inch seems excessive). Just check to see if it does it without the ac/defrost on.

 

[geeturbo]

Is the a/c or defroster on when this happens? When the compressor kicks on in these cars it will cause the engine rpms to change, and could cause a slight drop in the brake pedal (an inch seems excessive). Just check to see if it does it without the ac/defrost on.

I thought about that too. But no that's not the case. There is no rhyme or reason to when it happens. It seems when I leave from work everyday it happens at the same light everyday but then its a crap shoot when it happens again.......like I said, wierd

 

[Jayman212]

I had a similar issue with my new sonic 1.8 LT. Drove it off the lot and the brakes felt a bit grabby compared to the one i test drive. Got 43 kilometers on the odometer then suddenly the pedal started to drop an inch seconds after stopping the car. It progressed to the point where eventually the car would start moving on its own after stopping and the pedal would sink to the floorboards. Once it hit the floorboard it would stop rolling. Its currently in the shop awaiting a new master cylinder. Your issue is less extreme than mine but maybe your master cylinder is getting a bit weak. Just a though

 

[barch88]

Mine does the same thing, it's normal. Hitting floorboard and starting to move on its own is not.

 

[AxelRipper]

Mine does the same thing, but I always attributed it to the turbo. Figure there's a vacuum canister that it builds vacuum in while idling so when you go to use your brakes while driving (when there is no engine vacuum because turbo) your power brakes work well. I always figured when you get back to idle it uses some off the vacuum to stop, and then your pedal sinks lower when the vacuum builds up in the canister again.

Not sure if this would explain the 1.8 situation, but if they're using the same setup it makes sense.

 

[ahtoxa]

Mine does that as well. Normal in these cars, from what I can tell.

 

[Chevrolet Customer Care]

Hey jayman! Sorry to hear that your Sonic is in the shop. Please feel free to send me a message if you need any assistance or have any questions. I am here to assist you. Have a great holiday.

Jackie
Chevrolet Customer Care

 

[ramiro77]

Mine does that too.
And I´m from Argentina.
So I guess it´s normal.

 

[Larrymer]

Perfectly normal.