# No brakes at low speed? Pedal goes literally to the floor.



## GMNut (Jul 29, 2019)

I was visiting my in laws and they asked me to test drive their 2014 Cruze LS because the brakes were acting funny. So, I drove it, felt fine until I rolled to a stop sign and the pedal went to the floor like there was no fluid. It stopped finally and when I pulled up on the pedal, next one was hard as normal and we took off. Tested stops from 60, 40, 30, and then 20... under 10 there no pedal and it is intermittent. I can do stops from 10 5 times and 1 or 2 of them will be zero pedal and to the floor and you have to lift and get it pumped like the master is dead. So I figure swap and bleed the fluid, some air, nothing major. SAME issue!? I have a brake master on the way, but the way it is intermittent and just low speed tells me there is a sensor or something going on as well?


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## jblackburn (Apr 14, 2012)

The vacuum assist switch to trigger the vacuum pump has likely gone bad. I believe 1.8s had this; the 1.4s did. 

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## plano-doug (Jul 1, 2015)

jblackburn said:


> The vacuum assist switch to trigger the vacuum pump has likely gone bad. I believe 1.8s had this; the 1.4s did.


But if I lose vac, I should have stiff pedal, not pedal-to-the-floor, no?

That said, you made me go look. I did see (on my 2013 LS with 1.8) p/n 20998928 under the brake booster with a hose going to a T which in turn went to the booster and to the intake.

Googling that p/n turns up evidence that it is indeed a vacuum pump. But I'm stumped as to why a normally aspirated engine would need a vacuum pump - maybe it's impotent  Seriously, I guess the intake tuning function may somehow affect vacuum which results in the need for the external unit.

Back on point, pedal to the floor makes me think hydraulic issue rather than vacuum. But there may be something about the master cylinder I'm missing.

Doug

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## Blasirl (Mar 31, 2015)

GMNut said:


> I was visiting my in laws and they asked me to test drive their 2014 Cruze LS because the brakes were acting funny. So, I drove it, felt fine until I rolled to a stop sign and the pedal went to the floor like there was no fluid. It stopped finally and when I pulled up on the pedal, next one was hard as normal and we took off. Tested stops from 60, 40, 30, and then 20... under 10 there no pedal and it is intermittent. I can do stops from 10 5 times and 1 or 2 of them will be zero pedal and to the floor and you have to lift and get it pumped like the master is dead. So I figure swap and bleed the fluid, some air, nothing major. SAME issue!? I have a brake master on the way, but the way it is intermittent and just low speed tells me there is a sensor or something going on as well?


Welcome Aboard!

Don't forget to introduce yourself and your Cruze here.


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## jblackburn (Apr 14, 2012)

plano-doug said:


> But if I lose vac, I should have stiff pedal, not pedal-to-the-floor, no?
> 
> That said, you made me go look. I did see (on my 2013 LS with 1.8) p/n 20998928 under the brake booster with a hose going to a T which in turn went to the booster and to the intake.
> 
> ...


Low vacuum conditions occur during valve overlap events like cold/high idle even on N/A engines.

You'd think it would just be a stiff pedal with little braking, but I had a car with a leaky booster and the pedal sunk to the floor and very little happened to slow forward progress. There have been similar reports here when the vacuum pump stops functioning.









2014 Cruze brake issues PLEASE HELP!!


Hello, I am new to this forum and was hoping to maybe get some help or at least pointed in the right direction. I have a 2014 Cruze 2LT RS 1.4T wit 50k on the clock. I just started having braking issues. The pedal can be pushed all the way to the floor and sometimes the brake pedal will get...




www.cruzetalk.com


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## GMNut (Jul 29, 2019)

Can I just replace the switch, or does the whole assembly have to be replaced?


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## GMNut (Jul 29, 2019)

To clarify............ car off and bleeding, pedal was perfect. Stopping from random high speeds above 20, perfect pedal and stopping. Randomly creeping to a stop under 15-20... zero pedal. You can literally come to a stop with a perfect pedal, creep forward 5ft and then have no pedal unless you let off and pump again. but it doesn't do it every time.


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## GMNut (Jul 29, 2019)

jblackburn said:


> Low vacuum conditions occur during valve overlap events like cold/high idle even on N/A engines.
> 
> You'd think it would just be a stiff pedal with little braking, but I had a car with a leaky booster and the pedal sunk to the floor and very little happened to slow forward progress. There have been similar reports here when the vacuum pump stops functioning.
> 
> ...



*GM Brake Sensor 20876799*


That sensor?


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## snowwy66 (Nov 5, 2017)

Try using hard pressure. Then soft pressure. 

Usually a hydraulic might fail as it slowly bleeds past the seals. Causing pedal to go to the floor. With soft pedal pressure.

Course, that was 20th century breakdown.

Also. Make sure none of the tire brakes are leaking.


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## jblackburn (Apr 14, 2012)

GMNut said:


> Can I just replace the switch, or does the whole assembly have to be replaced?


I have only seen it sold as part of the whole line, and which one you buy depends on transmission.






Hydraulic System for 2014 Chevrolet Cruze | GMPartsDirect.com







www.gmpartsdirect.com


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## obermd (Mar 3, 2012)

GMNut said:


> To clarify............ car off and bleeding, pedal was perfect. Stopping from random high speeds above 20, perfect pedal and stopping. Randomly creeping to a stop under 15-20... zero pedal. You can literally come to a stop with a perfect pedal, creep forward 5ft and then have no pedal unless you let off and pump again. but it doesn't do it every time.


Definite symptom of either the vacuum switch or the vacuum pump going bad.


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## GMNut (Jul 29, 2019)

Thanks everyone. Ordered the pump and hose with the sensor in it just in case. Start with the simple stuff like the sensor then work my way up to the pump and then the master cylinder when I get back there this weekend. Trying to see if my scanner can control those components for testing. Regardless, I'll update this post with the fix for future use.


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## Blasirl (Mar 31, 2015)

Consider writing a How-To: as you do this fix. Add part numbers, symptoms, a few pictures would help as well. 

*How-To: Write a Tutorial*


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## GMNut (Jul 29, 2019)

Update:

Replaced the sensor, pedal no longer went all the way to the floor. Could hear the pump kicking on.
Replaced the master, success.


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