Brake Power Assist Failing at Parking Lot Speeds

[OR VietVet]

I do appreciate the time you took to respond. Candidly though, your attention comes with a condescension tax I'm not willing to pay. To wit, you haven't made any suggestions - you've just told me all the ways my question was poorly conceived.

Your advice hasn't been valuable enough for me to want to deal with your tone. So - best luck if we don't talk again.

I have no words for how slighted I feel right now. Tears=slippery floor.

 

[Miami-Dade]

I have a brake issue I want to run by you guys.

2016 Tahoe LT, about 86K miles.

Occasionally when I am at the end of a journey, either long or short, something fails or deactivates in the power assist for the brakes when I am moving the vehicle slowly into a parking position. I feel a change in the pedal feel, it seems to mash further down, and I have to apply dramatically more pressure to achieve stopping power.

The issue resolves when I turn the vehicle off and restart it, even with no delay. There are no warning lights or error messages. No visible issues with the brake hardware.

The issue never occurs at speed, thankfully as it would be very dangerous if it did. It only seems to happen when I'm inching the vehicle forward or backward slowly, as I do for instance when coasting it into the garage.

I've had the vehicle from new and it's always happened, maybe once a month or so. I haven't been able to draw any pattern between characteristics of the drive and this happening at the end of it. It might happen at the end of a 2 hour drive down from the mountains and it might happen after a 2 mile drive from the grocery.

Anyone experience this?

Just saw this post.

I my case [same issue as yours] it was the Brake Booster. Went out twice on me. Almost went threw a parking garage wall when the second one went out.

I could have sworn at the time [2017] the dealer said it was known recall. At the time my warranty was still in effect. Any good Chevrolet-GMC dealer should be fully aware of it as it happened to a lot of 2015-2016 vehicles.

 

[dnt1010]

https://www.fleetowner.com/equipmen...s-34-million-pickups-and-suvs-over-brake-pump I had a 2014 / 2016 / 2017 and 2018 GMC Sierras the 2016 did have this issue and was resolved under warranty. Pretty shocking that a reputable dealership service department is not familiar with a recall that large? Put your VIN in at that site and see what it pops up?

 

[THarber]

I think the recall is #N19226849. You should be able to search your VIN and see if any recalls are still out for it.

It more than likely will boil down to a bad vacuum pump or booster. They are not expensive repair items, if you can do it yourself you should get by for about $250. You might even connect a temporary vacuum gauge to the the line going from the pump to booster so that you can see what it does. Tee it off and put the gauge up near the windshield or something. Also if there is oil in this line, its a bad pump and will need replaced.

 

[Blackcar]

Here is recall in link, https://static.nhtsa.gov/odi/rcl/2019/RCSB-19V645-6988.pdf