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Vacuum pump & mechanics


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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. 

 

 

 

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  • 1 month later...

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

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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

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  • 1 month later...

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.

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  • 3 weeks later...

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.

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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?



Sent from my Moto Z2 Play using Tapatalk

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  • 9 months later...
  • 2 years later...

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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