By on September 11, 2019

2016 GMC Sierra with eAssist, Image: General Motors

General Motors is recalling 3.46 million examples of its largest models over brake degradation. The culprit is a wheezing vacuum pump that gradually loses its ability to function over time, resulting in underperforming brakes. Affected vehicles include all of GM’s big boys, including the Cadillac Escalade, Chevrolet Silverado, Chevrolet Suburban, Chevrolet Tahoe, GMC Sierra, and GMC Yukon from the 2014-18 model years.

The recall was preceded by a preliminary investigation from the National Highway Traffic Safety Administration, which launched in 2018 after reports of crashes and a couple of injuries surfaced. In December, GM followed up by extending warranty coverage for vacuum pump replacements for the suspect vehicles. The NHTSA sent its findings off to General Motors last July, but not before the automaker had recalled 310,000 vehicles in Canada over the same issue. A safety bulletin was issued in the United States this month. 

The good news is that the worst most drivers will have to endure is a super firm brake pedal, something easily managed if you’ve any experience driving high-milage trash. However, GM has said stopping distances could be impacted — making this a safety issue. Either way, it’s not something you’d want to live with for any length of time and will only get worse. Be on the look out for a “Service Brake Assist” warning and rippling leg muscles.

GM indicated that the pump filters were occasionally getting clogged by engine debris, specifically burnt-up oil that was original intended to lubricate the component. As the filter gets increasingly gummed up by sludge, the pump loses its ability to create an effective vacuum. Models built after the 2018 model year do not use the same system and are therefore in the clear.

Documents stated that GM will notify owners, and dealers will reprogram the brake control module to fix how the system uses the hydraulic brake boost assist function when there’s no more “vacuum pressure.” Gratis, of course. It does not appear the pump itself will be replaced, however.

The manufacturer does not yet have a timeline settled for those notifications yet, but you can keep tabs on the situation by following NHSTA’s or GM’s recall campaign (No. 19V-645 and N192268490, respectively).


[Image: General Motors]


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56 Comments on “Them’s the Brakes: GM Recalling 3.46 Million Vehicles in U.S....”

  • avatar
    Art Vandelay

    “The good news is that the worst most drivers will have to endure is a super firm brake pedal, something easily managed if you’ve any experience driving high-milage trash.”

    My high mileage garbage typically had a really spongy pedal.

  • avatar

    I wish they would of recalled the brakes on my 1999 Silverado. The rear discs, that only were around for a couple of years before they replaced them with drums, prematurely wore out because the parking brake wouldn’t release fully. I had to replace them twice. Then the ABS pump went out. That was a $1500 repair so I just pulled the fuse and lived without ABS, unfortunately it disabled cruise control as well.

  • avatar

    If I understand this correctly, the net effect would similar to what happened when the engine crapped out on my old Mercury Tracer while on the freeway – the power brakes lost pressure, so I ended up pushing down harder and harder on the brake pedal, with less effect.

    If that’s the case, then this is kind of terrifying – without power brakes, I barely got the Tracer to a stop, and this was a 2,500 pound compact, not some three-ton SUV.

    Good to know there are three and a half milion of these jank-braked rollling barns out there.

  • avatar

    How can a company not even get braking right? Or Ford messing up seats in their best seller? American companies are full of bad planning while jumping on latest electric trends.

    Meanwhile Toyota just keeps making old school but reliable vehicles. Long live Toyota.

    • 0 avatar

      …… whoa, I was getting concerned. I have not seen the Toyota marketing bot for a while. Next is the 1,000,000 mile Tundra with seats that look two days out of the factory, the Taco that climbed Mt Everest and won the BAJA 1000 without an oil change, or the FJ Cruiser that gets 39mpg while on the Texas interstate with the cruise set at 90mph.

      I’m no GM fan, but really. The whole My Toyota has 300K miles and I never checked or changed the oil silly me does not cut it here.

    • 0 avatar

      Long live Chairman Toyoda! Cheers.

  • avatar

    “Vacuum pumps”? These aren’t diesels we’re talking about (that don’t generate vacuum, and need a vacuum pump to generate vacuum to operate things), so what we’re talking about is problems with vacuum boosters, and hydraulic assist from the ABS controller.

    Also, the term “vacuum pressure” is an oxymoron. Vacuum is the absence of pressure.

    • 0 avatar

      No, we’re talking about vacuum pumps that provide more vacuum to operate the vacuum booster. The article is correct. And so is the NHTSA recall.

      (Just correcting the misinformation for anyone who comes across this later, nothing personal.)

  • avatar

    Why didn’t they use the vacuum from the intake manifold? That’s how they did it in the old days. I dare someone at GM to try to stop a full size truck with no vacuum assist, it’s not going to happen.

    • 0 avatar

      Some larger cars, like Lincoln Continentals and some Cadillacs in the ’70s, along with the GM 350 diesel cars and pickups, and cars that didn’t have room to fit a vacuum booster (and strangely, Chevy Astro Vans), used a hydraulic booster (“Hydroboost”) that ran off the power steering pump. It’s not unheard-of to use Hydroboost on cars with wild cams that can’t make enough vacuum (at least 13 in hg at idle) run a vacuum brake booster.

      Here’s a BangShift article where they converted a ’65 Impala SS from vacuum to Hydroboost, by using a junkyard Hydroboost unit out of an Astro Van, and modifying the power steering reservoir to add a return line:

  • avatar
    R Henry

    All my cars use engine vacuum to power the brake booster. Does anyone know why an auxiliary vacuum pump is used on these trucks?

    • 0 avatar

      They don’t. According to the recall, they use the ABS controller to assist the vacuum power assist. The term “vacuum pump” here is misleading.

      • 0 avatar
        R Henry

        From the NTSB bulletin:

        ” these vehicles may have a condition in which the engine mounted mechanical vacuum pump output may decrease over time, decreasing
        the amount of vacuum/power brake assist.

        “The vehicles’ vacuum assist pump is lubricated with engine oil, which flows
        into the pump through a filter screen. “

        • 0 avatar
          R Henry

          NHTSA, not NTSB. Sorry.

        • 0 avatar

          Why would they design in a vacuum pump? Do these engines not make enough vacuum? Things that used to run off of vacuum, like diverter doors and blend doors in the HVAC system, usually are run by electrical servos nowadays, so about the only thing vacuum is used for is to boost the brakes.

          I don’t see why they’d need a vacuum pump. It’s just another thing to wear out, which is usually a bad thing with GM products.

  • avatar

    With just one year of degradation? They’re still cutting corners on their #1 cow? They’re dead without this particular cow, and yet they treat it like this? They feed it essential brake components from the lowest bidder in China?

    Stupid. Door Handles I can understand, although what does that say about the non essential stuff? So where’s DeadWeight anyway.

  • avatar

    Welcome to Barra’s GM where share holder value is more important than quality. Why would anyone buy a GM truck over the superior offerings from Ford, FCA, and Toyota.

    • 0 avatar
      Peter Gazis


      When choosing a lover, would you go for:

      A) the high maintenance premadonna. That spends a ton of cash making herself look good (RAM)
      B) the Actress who can do her own stunts, but bruises real easily. Which limits the things you are willing to try. (Ford)
      C) the athletic girl next door. Who can keep up with you in the bedroom, and is always willing to try new things (GM)
      D)Sex is sex, male, female, animal, vegetable, mineral doesn’t matter. Being able to quickly get out of a relationship is all that matters (Toyota)

  • avatar

    My hypothesis: Longer oil change intervals cause more sludge which clogs the filters.

  • avatar

    “Premature degradation”. I believe that’s the term that was used in a recall involving my 2002 Silverado at the time when the Chinese made tailgate cables were corroding from the inside to the point of breaking. Both of mine broke while I was standing on the tailgate causing me to slip down and crack my elbow. Luckily I wasn’t loading my ATV or something.

    Way to go on the quality, GM.

    Perhaps I shouldn’t have been standing on it but I have done that on other trucks without issue.

    • 0 avatar

      A tailgate should taco from an overload before the cables let go.

      Users normally put 500 lbs on them or more, although I’m not aware of an official weight rating. I do it, with caution, but three big dudes sitting on the tailgate can be lots more than that.

      I saw a video of a Silverado lifted from the back by a forklift, forks lifting from the loose tailgate, way up high.

      The cables were lifting around 1,000 lbs each. They were screwing with a junk ’00 era Silverado and it wasn’t that old, but definitely totaled by rust.

    • 0 avatar
      Peter Gazis


      That must of cost you about $20 and a few minutes out of your day to repair. Hope you didn’t need to take out a second mortgage to come up with the cash.


  • avatar

    So, after reading a little more about the recall, it appears that this recall is pretty much the exact counterpart of the infamous Ford “sticker recall.”

    GM is not actually being forced to fix the vacuum pump problem at all. (They don’t actually seem to have a solution to the mechanical problem.)

    GM is apparently re-programming the truck’s computer to flash the warning message sooner, before the vacuum pump degrades so far that it can’t stop the vehicle.

    This basically makes it a minor stopgap at best, and a recall with very little in the way of teeth. It seems that many vehicles will now be out of warranty, so GM will be able to charge their customers for new vacuum pumps. Those pumps will probably fail again soon because they are the same or a similar design, so then GM gets to charge them again down the road.

    (Side note – fighting and dragging your feet on doing the right thing is tempting for these companies because it lets them avoid lots of warranty expenditures. A moral hazard, for sure.)

    (Second side note – Is a hard brake pedal easily handled? In a passenger car, if you’re a strong young man, yes, probably. In a loaded full-size truck on a downhill grade, pulling a trailer at highway speeds, and you’re a 100-pound granny, uh … no.)

    (Third side note – The hard brake pedal would be bad if paired with Ford’s seatback strength recall. Push – PUSH – SNAP!!!)

    Perhaps this weak recall will open the door to a real recall later on. I guess we’ll see.

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