2021 Silverado brake pedal goes to the floor

[Catchesbass]

I’ve had my truck since November 27. I have less than 800 miles on it and today on two occasions the brake pedal went all the way to the floor when starting the truck. I got in, pressed the brake, hit the start button and the pedal went to the floor. It only happened twice. It’s at the dealership now but they can’t seem to duplicate the issue. I’m seriously concerned about the safety of driving a truck with a brake issue. Especially since tournament season starts soon and I’ll be pulling a boat several days per week. Anyone else have this issue and know of an easy fix to put my mind at ease? So far it hasn’t given me a problem when driving but there has to be a reason why the pedal went to the floor those two times. I can only imagine what could happen if that happened while towing my boat. I had hell with the radio issues and those are mostly fixed but this brake issue is just spooky. 

[puppykat33]

did you get the fix for this?

[Transient]

There's no brake issue. Like you said, it's only before startup. My peddle goes almost all the way to the floor when I get in the truck before I press the ignition button. Once the truck is running the peddle feels like a normal peddle. Did you notice there's also no place under the hood to fill the brake fluid reservoir? That's because there isn't one. These new trucks have an interesting (aka, witchcraft) brake system. After all, if the engine turns off at a stop light the truck doesn't roll backwards when you let off the brakes and it restarts. Same wizardry, in my opinion.

Sent from my SM-N960U using Tapatalk

[Catchesbass]

No fix that I’m aware of. Mine only does it every once in a while. The good thing is the brakes still seem to work fine. Note that first shift from first to second in the morning is a doozie. 

[Tahoe02]

Maybe they can reprogram the tranny. It should not shift like that. Good luck.

[Catchesbass]

It has done it since day one. The dealership and gm both tell me it’s normal. Of course they do 

[Tahoe02]

Pick another one from their lot and tell them lets go for a ride. I'm sure it won't be normal.

[Catchesbass]

It only does it on the first trip in the morning. After that it’s good all day. They say it’s something about the torque converter building pressure or some BS. I’ll have them dig into it more when I get the oil changed but I’ve only got 1400 miles on it right now and I’ve had it since November. It may be a while. 

[Tahoe02]

I have a 2020 Trail Boss and no shift issues no matter first shift or last shift. Nothing like a neck snapping shift first thing in the morning to start off your day. Don't give up which I'm sure there hoping you will do. For what we pay for these they need to function properly. Good luck and I hope you get it sorted out.

Edited March 2, 2021 by Tahoe02
*

[Catchesbass]

I wonder if they did anything different to the 8 speed transmissions in the 2021 models. 

[2016 Sierra Owner]

On 3/1/2021 at 5:25 AM, Transient said:

There's no brake issue. Like you said, it's only before startup. My peddle goes almost all the way to the floor when I get in the truck before I press the ignition button. Once the truck is running the peddle feels like a normal peddle. Did you notice there's also no place under the hood to fill the brake fluid reservoir? That's because there isn't one. These new trucks have an interesting (aka, witchcraft) brake system. After all, if the engine turns off at a stop light the truck doesn't roll backwards when you let off the brakes and it restarts. Same wizardry, in my opinion.

Sent from my SM-N960U using Tapatalk
 

It's got a reservoir. It's just not in the place it used to be. It's lower on the fire wall. Here is the unit that is in our trucks now.   https://gmauthority.com/blog/2018/10/zf-highlights-brake-by-wire-system-in-silverado-sierra/

 

 

[redwngr]

 

 

5.3L V8 Engine (L84) Shown, 5.3L V8 Engine (L82) and 6.2L V8 Engine (L87) Similar

 

 

1. Remote Negative (–) Location. See Jump Starting - North America 0 389.
2. Positive (+) Terminal (Under Cover). See Jump Starting - North America 0 389.
3. Battery - North America 0 341.
4. Engine Compartment Fuse Block 0 351.
5. Engine Oil Dipstick. See “Checking Engine Oil” under Engine Oil 0 328.
6. Engine Cooling Fans (Out of View). See Cooling System 0 333.
7. Engine Oil Fill Cap. See “When to Add Engine Oil” under Engine Oil 0 328.
8. Coolant Surge Tank and Pressure Cap. See Cooling System 0 333.
9. Engine Air Cleaner/Filter 0 332.
10. Brake Fluid Reservoir. See Brake Fluid 0 341.
11. Windshield Washer Fluid Reservoir. See “Adding Washer Fluid” under Washer Fluid 0 338.

 

 

[Transient]

It's got a reservoir. It's just not in the place it used to be. It's lower on the fire wall. Here is the unit that is in our trucks now.   https://gmauthority.com/blog/2018/10/zf-highlights-brake-by-wire-system-in-silverado-sierra/
 
 

Thanks for posting this. I stand corrected. I went and looked and found the brake fluid tank. It's under the coolant overflow tank. The brake fluid tank cap is recessed and can be found at the firewall between the coolant overflow tank and left side inner fender. Looking from the front you'll never see it because the air box obstructs the view. You'll need to be standing next to the truck, right on front of the driver's side mirror.

Sent from my SM-N960U using Tapatalk

[aliveguy5]

My truck has done this on occasion and my buddy's 2020 HD chevy did as well. As soon as the truck started the brake pedal was perfect with no other issues ever. I know it's fun to say the dealership "says it's normal" and then complain, however this is normal.