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Vacuum pump & mechanics

Adam Leinss
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squeak93 Enthusiast

squeak93

Posted
Posted

Yes I assume it’s bumper to bumper.  Which ends next feb for me so at least it happened now. No way they classify this as a power train item. 

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300 Blackout
300 Blackout

That depends if oil was found in your vacuum line. If it was then the recommendation is to replace the additional parts of the braking system. If no oil was found in the line and they don’t suspect oi

newdude
newdude

AFM is why. It allowed them to change the AFM so it runs more with low/no load. When you drop 4 cylinders, you drop your vacuum supply. Helps for added brake assist to increase pedal feel over the

montytx
montytx

This happened to me today. Ordering a new pump. I can tell you this, you have to push down really hard to bring these to a stop. I assume they included them in the engine because they drop to 4 cyl.

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Katie989 Enthusiast

Katie989

Posted
Posted

I had this happen to me a couple weeks ago. Power Assist failed while backing into a parking spot. Brought it to the dealer and they replaced the brake booster. I was originally able to reproduce the problem  (as it went away) and can’t anymore but I still feel like something is wrong with the brakes. When I press the brakes frequently in traffic I feel like the peddle gets higher and harder but then reverts to normal. Also, if I start the truck and then turn it off and press the brakes I have 6 depressions until the vaccume is used up. But if I start the truck, turn it off and wait 5 hours the peddle is rock hard. Sign of a leak? Anyone else have a hard brake peddle in the mornings or after the truck sits for a bit?  I tried explaining this to the dealership today and I don’t think I got anywhere.  Maybe it’s normal but I just don’t see it. 

 

 

 

squeak93 Enthusiast

squeak93

Posted
Posted

They need to replace the vac pump. Booster. Lines and master cylinder.  The vac pump goes Bad and pumps engine oil through them booster.  

  • 1 month later...
Chevymaffia New Member

Chevymaffia

Posted
Posted

2015 Tahoe LT 5.3l 4x4

Happened to me this week. Nov 28th in stop and go traffic I lost boost and rearended someone at about 8mph, initially going about 15. 

Someone on here said there’s no safety issue and you just need to press harder, negative. I stood on it and I got physical pushback from the pedal. 

I had notice in the last month I had some unusual brake fade, mostly at very slow speeds in parking lots, and possibly in 4cyl mode. So a month ago I had the GM service department at James Woods Chevrolet inspect the the vehicle with an oil change, that gave me the all clear. 

Today, Nov 30 2018 they tell me my vacuum pump needs to be replaced... NO s*%#! 

 

Now granted.... I have 107,700 miles on my tahoe, but these are all cruising speeds cross country visiting family in MD to Vegas to MO, all from Dallas. Very little stop and go. My average speed on the vehicle is 46mph.

 

Just a touch over 3 years old, and this failure happens. Unacceptable. Especially since my 2007 Silverado has over 200k miles, my old 2004 Silverado has 280k miles, my 92 Silverado has 170k miles, my 2009 Avalanche had 190k miles, and none, not a single one has had a vacuum issue of any kind. 

 

Im keeping the parts on hand and going to push this issue further. Also reported the incident with DOT

 

 

03ECC466-8756-4C4F-AC19-A283C8F3B8C5.jpeg

2018GMC Senior Enthusiast

2018GMC

Posted
Posted
2 hours ago, Chevymaffia said:

2015 Tahoe LT 5.3l 4x4

Happened to me this week. Nov 28th in stop and go traffic I lost boost and rearended someone at about 8mph, initially going about 15. 

Someone on here said there’s no safety issue and you just need to press harder, negative. I stood on it and I got physical pushback from the pedal. 

I had notice in the last month I had some unusual brake fade, mostly at very slow speeds in parking lots, and possibly in 4cyl mode. So a month ago I had the GM service department at James Woods Chevrolet inspect the the vehicle with an oil change, that gave me the all clear. 

Today, Nov 30 2018 they tell me my vacuum pump needs to be replaced... NO s*%#! 

 

Now granted.... I have 107,700 miles on my tahoe, but these are all cruising speeds cross country visiting family in MD to Vegas to MO, all from Dallas. Very little stop and go. My average speed on the vehicle is 46mph.

 

Just a touch over 3 years old, and this failure happens. Unacceptable. Especially since my 2007 Silverado has over 200k miles, my old 2004 Silverado has 280k miles, my 92 Silverado has 170k miles, my 2009 Avalanche had 190k miles, and none, not a single one has had a vacuum issue of any kind. 

 

Im keeping the parts on hand and going to push this issue further. Also reported the incident with DOT

 

 

03ECC466-8756-4C4F-AC19-A283C8F3B8C5.jpeg

https://www.gm-trucks.com/forums/topic/216957-gm-under-investigation-for-faulty-brake-vacuum-pumps/?do=findComment&comment=2175412

  • 1 month later...
FedUpChevyOwner New Member

FedUpChevyOwner

Posted
Posted

Everyone that has had this issue no doubt needs to report it via https://www-odi.nhtsa.dot.gov/VehicleComplaint/  Was backing down a drive way that was pretty steep riding my brakes and without warning BRAKES WERE STIFF AS HELL! Had to stand up on it adrenaline was all that helped me stop it.  It is indeed the Vacuum pump/booster (not cheap either).  What a joke ive seen hundreds of complaints on this, but no recall makes no sense, save your receipts i'll be getting a 3rd party to do mine with an aftermarket upgrade no doubt.

  • Like 1
  • 1 month later...
  • 3 weeks later...
SkunKnuckles New Member

SkunKnuckles

Posted
Posted

Same happened to me last oct or nov on my 2015 1500 LTZ, not long after the warranty went out.  It's barely got more than 30,000 mi.  It sat around until I got around to ordering the parts from gmpartsgiant for $135.07.  

 

Today I began the adventure.  For a few hours, it went cursingly poorly since I couldn't reach all the bolts.  Eventually I removed the steering column (I removed only two bolts), and then it went about normally.  It got dark before I got the pump out -- the bolts are out but there's a plastic wiring channel that seems to be plastic riveted to the vacuum pump.  

 

I expect I'll pry it out with a screwdrive in the light of a new day, switch out pumps, replace the steering column, replace the under-engine panel, and be done.  BTW, as near as I could tell, there was no oil in the vacuum hose or in my master cylinder.

 

Bottom line: if you're going replace the suburban's vacuum pump, do yourself a favor and remove the steering column.  It takes all of 5 minutes and could save hours of frustration.

  • Like 1
Mozzer Enthusiast

Mozzer

Posted
Posted

For anyone who has a vac pump that hasn't gone bad, yet... Is there any possibility of putting a screen / filter in line so that if it does die the rest of the booster system & engine won't ingest oil & metal?



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  • 9 months later...
Adam_Leinss New Member

Adam_Leinss

Posted
Posted

Looks like GM is finally addressing this issue and will cover all costs.  I got a letter in the mail 2 weeks ago describing the problem I was having.  I submitted my bill to Detroit and I'm waiting for response.

  • Like 1
  • 2 years later...
Lane Cheney New Member

Lane Cheney

Posted
Posted

This happened to my 2019 GMC Terrain last week. I found there is a recall for trucks, but checked my Vin number and mine is not. Also found where GMC is being sued over. Luckily wasn't needing to brake quickly. When happens very hard to stop and need plenty of room. We checked the vacuum pump and sure enough wasn't working at all. 

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