LOST BRAKING POWER AT VERY LOW SPEEDS

[Dnt]

If the vacuum pump was weak it makes perfect sense that during a parking maneuver you would lose boost as that is typically when you are constantly on and off the brake and engine is idling, it probably is using more vacuum than a weak pump can supply at low engine rpm. Interesting. I guess we all need to test the system every few months by pushing on and off the brakes (engine idling)  like 20 times and see if it holds boost LOL Thanks for the post, I will do this before I pull out of the driveway in the morning.  Can never be too careful when it comes to today's super complicated rolling electronic time-bombs. We need a complete preflight check before takeoff!!!!

[big papa]

I think this is happening on my truck.  Its getting lifted today, will this be a fight for warranty work.

[Sierra Dan]

Vacuum Pump no Bueno.

[big papa]

is it a fast fix?  do they keep the truck long?   

 

[Robinson99]

I've had this issue now for several months.  I told the dealer what it was doing but it would come and go, they were never able to witness it. I finally had the issue and took it to the shop while it was happening, they told me I was getting 12psi and should be getting 27psi from the vacuum pump. It's getting replaced next week, but now I'm wondering if they will replace everything or just the pump. I have 60,000 miles on my truck, the shop worked with me under some program, original quote was $575 now reduced to $110.

[Travis1024]

I've got mine at the dealership right now for the same issue. The service tech is claiming that the weight of my wheels and tires is what is causing this, which I think is absolutely bogus. My truck is leveled with OEM GM 20s and 33s. probably 10 lbs/each heavier than stock (tops).

 

I asked them to throw some takeoff wheels and tires on and see if it persists, and they said the only way they could be sure is if I take my 2.5" level off too and bring everything back to stock. Crazy right? Why would the slight change in suspension geometry have ANYTHING to do with the ABS system functioning correctly at low speeds? 

 

Another huge issue is they say that this will likely NOT be covered under my 100k warranty because though they can replicate the issue EVERY SINGLE TIME, they can't prove that there is any "failure of parts".

 

Someone please help with ideas. I feel like I'm in a parallel universe right now....

[Robinson99]

On 3/1/2019 at 2:18 PM, Robinson99 said:

I've had this issue now for several months.  I told the dealer what it was doing but it would come and go, they were never able to witness it. I finally had the issue and took it to the shop while it was happening, they told me I was getting 12psi and should be getting 27psi from the vacuum pump. It's getting replaced next week, but now I'm wondering if they will replace everything or just the pump. I have 60,000 miles on my truck, the shop worked with me under some program, original quote was $575 now reduced to $110.

Update, my dealer took care of the cost.  I'm at 60,000 miles, I was happy they were able to take care of it for me.  Truthfully, I didn't expect them to but was very happy they did.  That's the kind of service that earns loyal customers, other dealers should take notice.

[SS502]

3 hours ago, Travis1024 said:

I've got mine at the dealership right now for the same issue. The service tech is claiming that the weight of my wheels and tires is what is causing this, which I think is absolutely bogus. My truck is leveled with OEM GM 20s and 33s. probably 10 lbs/each heavier than stock (tops).

 

I asked them to throw some takeoff wheels and tires on and see if it persists, and they said the only way they could be sure is if I take my 2.5" level off too and bring everything back to stock. Crazy right? Why would the slight change in suspension geometry have ANYTHING to do with the ABS system functioning correctly at low speeds? 

 

Another huge issue is they say that this will likely NOT be covered under my 100k warranty because though they can replicate the issue EVERY SINGLE TIME, they can't prove that there is any "failure of parts".

 

Someone please help with ideas. I feel like I'm in a parallel universe right now....

It all sounds iffy to me, but I do know that my dealership installed my level and told me at the time, the most they could go without warranty issues in the 2.25 level. They did that, and also limited my tire size to 275/60 R20.....regardless it sounds crazy to me.

[Travis1024]

On 3/7/2019 at 11:55 AM, Travis1024 said:

I've got mine at the dealership right now for the same issue. The service tech is claiming that the weight of my wheels and tires is what is causing this, which I think is absolutely bogus. My truck is leveled with OEM GM 20s and 33s. probably 10 lbs/each heavier than stock (tops).

 

I asked them to throw some takeoff wheels and tires on and see if it persists, and they said the only way they could be sure is if I take my 2.5" level off too and bring everything back to stock. Crazy right? Why would the slight change in suspension geometry have ANYTHING to do with the ABS system functioning correctly at low speeds? 

 

Another huge issue is they say that this will likely NOT be covered under my 100k warranty because though they can replicate the issue EVERY SINGLE TIME, they can't prove that there is any "failure of parts".

 

Someone please help with ideas. I feel like I'm in a parallel universe right now....

Just wanted to provide an update for anyone who may experience this issue moving forward -

 

After a little more research - I found that there is a service bulletin from GM around this issue, and it seems to be very common in 2014-2017 GM full size Trucks/SUVs. There is also a class action lawsuit against GM for safety issues, around them continuing to install knowingly faulty brake components on their vehicles.

 

Dealer persisted to say that my truck not having the stock suspension and having 33s was the issue that my power brakes were not working. They also stated that this will not be covered under warranty after they "fought with the warranty company for 4 days". (I actually called the 3rd party warranty company myself and they said there was no claim associated with my VIN#). They then told me that they needed to replace my brake booster, vacuum pump, master cylinder, and all associated hosing/connections - costing me over $2,000 out of pocket.

 

Needless to say, I picked my truck up immediately and brought it to a buddy of mine's shop. ** Issue was bad Vacuum pump **. Luckily I caught this before it could in turn damage the brake booster, causing more issues.

 

My shop replaced this, and got this covered under my 100k extended warranty. My only out of pocket cost was my $100 deductible. They also checked all other components to make sure they were functioning as designed. I've had the truck back for about 24 hours now and (knock on wood), everything is functioning as it should be, and I haven't seen the issue that I once saw every time I drove the truck.

 

Moral of my story? Never trust your dealership. They will try to screw you all day long. That is, until they run into someone who knows their shit, does research, and that they cant take advantage of.....

 

 

[BatmanLT]

Why in the world would they lubricate a pump in such a fashion brake components are sensitive to this issue ???? Comon GM!!!! Did you guys not learn from the ignition switch problem??

I have not had this problem yet but I did get the reimbursement form to get the money back for the repair 

Sounds like they need to make this a recall and retrofit a electronic pump like on the corvette heck some of these trucks cost as much as a vette or even more.

 

 

Edited May 2, 2019 by BatmanLT
Add ons

[tonyrb]

Is anyone experiencing a soft brake pedal with this issue? My brakes almost didn’t work today at low speeds when I was parking. My symptoms sound similar to a vacuum pump failure but my pedal felt soft when I had to put it to the floor to stop my truck. Some guys say the pedal will be stiff with pump failure but mine was not.

[Sierra Dan]

Speaking of Never Trusting Your Dealership.....    I thought I had heard it all until I read this :

 

Bought a 2015 Silverado 1500 lt double cab 5.3L V8 4x4 with 12,000 miles on it a couple months ago. It now has just under 20k miles and when I went to check the oil there where metal shavings on the end of the dipstick. Concerningly big metal shavings. I brought it in to my local GM dealer and they told me that it's from the dipstick scraping on the dipstick tube. They didnt run any tests on it they just drained it and looked in the oil itself and didnt find any shavings (so they said). Which sounded a little shady to me so I started looking to see if anyone else had this problem and I found a few cases similar but not enough for me to come to a solid conclusion. The pickup runs great and I dont hear or feel any problems but any insight would be greatly appreciated. I thought about sending a sample to be tested myself but I dont know of any good company's near me that do it. Any recommendations on that would great too. Thanks

 

 

Now is that response/explanation from his dealer just from left field or what?

 

 

Entire thread here:

 

 

 

Edited May 8, 2019 by Sierra Dan

[wforrest08]

15 hours ago, tonyrb said:

Is anyone experiencing a soft brake pedal with this issue? My brakes almost didn’t work today at low speeds when I was parking. My symptoms sound similar to a vacuum pump failure but my pedal felt soft when I had to put it to the floor to stop my truck. Some guys say the pedal will be stiff with pump failure but mine was not.

If you haven’t yet check your brake fluid level. Soft pedal is the first sign of a leak.

[Bash74]

When I got this in the mail I took it to the dealer and they just went ahead and did the work. If people paid for it already then there is also a form to fill out and get reimbursed.

[Baytrucker]

I got this notice too. I swear to god GM has done everything in their power to ensure that I get no enjoyment out of this stupid truck. I'm a year and a half driving my 2017 Sierra and I've already decided its the last GM product I ever buy.

 

Failed condenser and they give me a hassle. If the dealer hadn't pressed on my behalf, GM would have told me to get bent (and I'm still under warranty). They tried to get out of fixing my condenser because of "irregular oil changes". I basically follow the computer rather than the schedule. 

 

My truck shakes, rattles, thunks, shudders and makes strange noises and GM tells me its all normal. Then I finally decide to ignore all that and try to live with it (cause I'm never going to get it fixed under warranty) and they send me a note in the mail telling me my brake pump has a high probability of failing and there is nothing they are going to do about it to prevent it.

 

My wife won't drive the truck anymore. She doesn't feel safe. 

 

I'm not the swearing type, but seriously, F**k GM!