Im currently having braking issues with my 2010 Chevy HHR My Abs and Traction Service Lights come on im having a problem to where im having a mushy brake peddle and its sinks to the floor until coming to a complete stop I took it to the repair shop and was told that it was my two front hub bearings and needed some repair in the abs harness in the rear got that work done almost a 700$ repair picked up rained the next day drove around same problems occurred was told by the mechanic that sometimes when it rains it messes with the lights but i was still having the sinking problems with my brakes told me to turn off car for about 10-20mins and the lights should turn off waited about 30mins and the light where still on took it back in they came to a conclusion where my master cylinder and brake booster needed to be replaced okay im upset about this because i thought they would of found this out the first time and had a few words with them about getting it fixed and they replaced these parts at no charge with GM parts now i received the car back and it drove fine i travel for work so i went to SC and it drove fine all the way out there but then it rained and my lights kicked on and was doing the same thing with the sinking brake pedal and right now im currently back in TX and the car is back in the shop now they are saying its because i have a different size rim & tire which could cause my light to come on? which doesnt make sense to me on why my abs light would come on and my brake pedal would sink to the floor but im only having this problem with heavy down poor i did some research and i keep coming across having a faulty or bad abs module could this be a problem?

 

Welcome to the site, Yes, a faulty hub assembly or wires could cause the issues you explained.

 

Bad hubs don't explain the pedal falling to the floor and not stopping! That is a hydraulic problem no relation to rain. Usually Master cylinder, wheel cylinder or booster.
Yes, different size tires will cause ABS and Traction warnings. Why do you have that situation?
Rain could trigger faults that light those warnings in any number of wires shorting out, not having to do with brakes. It is a computer thing, you wouldn't understand.
I am surprised you don't mention a CheckEngineLight, you should get the codes read to see if any are lurking around; and definetly get the ABS codes read when the warning lights are on. Get the code numbers and post them here, most Advance/O'Reilly etc auto parts store can do it for free.

The ABS and traction control use the wheel speed sensors; if one or two wheels are turning at different rates the errors are triggered.

 

I had bought the car off a buddy of mine and i didn't realize the wheel until the mechanic had told me about it before i took it it i did get the code read and the codes that came up was U2106, C0035, C0460 this is before i took it to the mechanic cleared the codes and took to the mechanic for work and those codes never came up again and even when i got the repairs done i would think it would be good to go but only when it rains the lights come on and i have that sinking pedal problem even the next day after the rain cleared and all was dry i took it for a spin the lights came off then came on when at a stop light and my brake pedal when to the floor and even on my way home from my work trip no rain or anything i was coming to a light which turned red and slammed the brakes which stopped but went soft as it was stopping but i had to push all the way to the floor

 

C0035 means the LF wheel speed sensor/hub has a problem, C0460 means the steering position sensor has a problem and U2106 means the power supply for the TCM has a problem.

Any of those will cause the ABS/traction warnings and might be caused by water intrusion.
But, none of them could cause the dead pedal. Don't drive it until that gets fixed. If the shop couldn't fix that they don't know brakes, find a new shop.

I am getting a bit concerned; this is the third or fourth instance recently. On what planet is a car with no brakes a good idea? Just because you didn't kill somebody the first time it happened does not mean you never will.

 

Hopefully your advice regarding not driving it, is taken to heart Don, before someone gets killed.

 

On my 2006, when one of the ABS sensors was going out it would randomly activate ABS while at low speed and would actually pull the pedal all the way to the floor. I think the malfunctioning sensor was, in turn, making the pressure in the ABS module all wonky and causing the pedal to go to the floor. Pulling the fuse for the ABS system resulted in much more responsive braking and no pedal to the floor. I drove it like that until I got my Camry