SS Emergency Vacuum Reserve

cmfhsu · 02-27-2020, 07:32 PM

Hey y'all - I noticed my SS's emergency brake vacuum only lasts about a week or so before the pedal becomes fully firm again. In other words, the reserve vacuum that maintains brake boosting functionality only lasts about one week when I let my Camaro sit. Afterwards, my brake pedal is full firm as I go to start my car.

Is this in line with what you see on your cars? Should I be worried about a slow vacuum leak?

TJay74 · 02-28-2020, 09:37 AM

i am confused as to what your question is, the vacuum booster starts to lose vacuum the moment the engine is turned off.

oneredry · 02-28-2020, 09:53 AM

..and your emergency brake is driven electronically not by vacuum.

ctrlz · 02-28-2020, 10:57 AM

Quote:

Originally Posted by oneredry

..and your emergency brake is driven electronically not by vacuum.

And the pedal moves the pistons which apply the disc brakes. The E-brake is a drum style system internal to the rear rotor. Brake pedal has no effect on that.

arctic rs 52 · 02-28-2020, 05:17 PM

Quote:

Originally Posted by cmfhsu

Hey y'all - I noticed my SS's emergency brake vacuum only lasts about a week or so before the pedal becomes fully firm again. In other words, the reserve vacuum that maintains brake boosting functionality only lasts about one week when I let my Camaro sit. Afterwards, my brake pedal is full firm as I go to start my car.

Is this in line with what you see on your cars? Should I be worried about a slow vacuum leak?

Hello,new guy here, yes that's normal, Power brakes work off engine manifold vacuum,when the motor is turned off a valve closes too maintain vacuum for a period of time. A week is an above average time frame. hope this helps.

cmfhsu · 02-29-2020, 05:51 AM

Apologies for the confusion, ladies and gents.

arctic rs 52 has the right idea - the power brakes, which work off manifold vacuum, have (or at least had, idk about today) some sort of check valve which allows the power brakes to work in case the engine stalls while driving. In previous cars of mine, I've been able to let my car sit for over a month without losing vacuum out of that check valve - my Camaro only lasts one week.

It's a bit of an odd question, I totally agree. I'd just like to know whether I need to bring my car in for warranty service with some experiences from y'all. For those of you who let your camaro sit for more than a week at a time, is your brake pedal rock hard when you go to start the car?

arpad_m · 02-29-2020, 08:54 AM

Quote:

Originally Posted by cmfhsu

Apologies for the confusion, ladies and gents.

arctic rs 52 has the right idea - the power brakes, which work off manifold vacuum, have (or at least had, idk about today) some sort of check valve which allows the power brakes to work in case the engine stalls while driving. In previous cars of mine, I've been able to let my car sit for over a month without losing vacuum out of that check valve - my Camaro only lasts one week.

It's a bit of an odd question, I totally agree. I'd just like to know whether I need to bring my car in for warranty service with some experiences from y'all. For those of you who let your camaro sit for more than a week at a time, is your brake pedal rock hard when you go to start the car?

Yep, it is for me. Brakes behave normally after starting the engine, so I never thought this would be something to try and get serviced.

cmfhsu · 02-29-2020, 03:05 PM

Interesting - thanks for the feedback, arpad_m. Gives me a lot more confidence my car isn't subtly broken in a way I'll have to fight my dealer about.

Thank you!

nancygrl · 02-29-2020, 07:28 PM

I've had it happen twice, not worried as it's always been after not driving for a week or longer and only during the winter and pedal is normal after starting up.

arpad_m · 03-02-2020, 03:17 PM

Just brought the car out of hibernation a few hours ago, same rock hard brake pedal as always after several weeks of non-use. And everything was normal again once I started the engine.

jeep_junkie · 03-02-2020, 08:03 PM

A week is a long time for the brake booster to hold a vacuum. No big deal if the pedal goes firm after the car has been sitting so long.

cmfhsu · 03-03-2020, 06:26 PM

Thank you all for your responses; I really appreciate it. I seem to remember my Fiesta ST lasting over a month, but I didn't have to press the brakes to start it, so maybe I just never stepped on the brakes before starting the car.

02-27-2020, 07:32 PM	#1
cmfhsu Drives: 2019 2SS 1LE Join Date: Aug 2019 Location: CT Posts: 112	SS Emergency Vacuum Reserve Hey y'all - I noticed my SS's emergency brake vacuum only lasts about a week or so before the pedal becomes fully firm again. In other words, the reserve vacuum that maintains brake boosting functionality only lasts about one week when I let my Camaro sit. Afterwards, my brake pedal is full firm as I go to start my car. Is this in line with what you see on your cars? Should I be worried about a slow vacuum leak?

02-28-2020, 09:37 AM	#2
TJay74 Drives: 17 Camaro SS 1LE & 16 Sierra AT CC Join Date: Nov 2016 Location: Norman, OK Posts: 2,424	i am confused as to what your question is, the vacuum booster starts to lose vacuum the moment the engine is turned off. __________________ 2019 Corvette Z06 2LZ A8 - Halltech CAI, AWE non-catted X-pipe, Mamo V2 ported TB 592rwhp, bone stock 566rwhp 2017 Camaro SS 1LE - Procharger D1SC w/ Tial 2" BOV & Race intercooler / ARH full length catless headers / Alky meth injection system - 650rwhp on conservative tune SOLD

02-28-2020, 09:53 AM	#3
oneredry HYPER SS Drives: 2016 Supercharged 2SS Join Date: Feb 2014 Location: Troy OH Posts: 1,252	..and your emergency brake is driven electronically not by vacuum. __________________ Ordered: 1/15/2016 2000 status 02/01/16 3000 status 02/29/16 3400 status 03/07/16 TPW of 03/14/16 4200 status 03/17/16 in transit! Delivered 03/23/16 2SS Hyper Blue \| 6M \| NPP \| Mag ride \| ceramic white Int. \| Black out bow ties \| P3 Gauge\| Front splitter. \| 6 pot upgraded brembo brakes. \| Magnuson Supercharger/95MM pulley \| Rotofab Intake \| ZL1 side skirts \| HRE FF04 wheels - Michelin PSS4 \| ZL1 add ons rock guards and lift points. \| AWE touring - resinated catback with link pipes.

03-02-2020, 03:17 PM	#10
arpad_m Drives: 2018 Camaro 2SS A8 Join Date: Jul 2017 Location: East Tennessee Posts: 11,616 View My Garage	Just brought the car out of hibernation a few hours ago, same rock hard brake pedal as always after several weeks of non-use. And everything was normal again once I started the engine. __________________ 2018 Camaro 2SS — G7E MX0 NPP F55 IO6 735 rwhp \| 665 rwtq Magnuson TVS 2300 80mm pulley \| Kooks 1 7/8" LT headers \| JRE smooth idle terminator cam \| LT4 FS & injectors \| TSP forged pistons & rods JMS PowerMAX \| DSX flex fuel kit \| Roto-Fab CAI \| Soler 95mm LT5 TB \| 1LE wheels \| 1LE brakes \| BMR rear cradle lockout \| JRE custom tune 1100 - 1/30/18 \| 2000 - 1/31/18 3000 - 2/06/18 TPW 2/26/18 3400 - 2/19/18 \| 3800 - 2/26/18 4300 - 2/27/18 \| 4B00 - 3/01/18 4200 - 3/05/18 \| 4800 - 3/14/18 5000 - 3/16/18 \| 6000 - 3/19/18

03-02-2020, 08:03 PM	#11
jeep_junkie Drives: 2000 Trans Am M6 Join Date: Mar 2018 Location: Dublin, CA Posts: 134	A week is a long time for the brake booster to hold a vacuum. No big deal if the pedal goes firm after the car has been sitting so long. __________________ *2018 - 1SS - 1LE* - Red Hot**

02-29-2020, 05:51 AM	#6
cmfhsu Drives: 2019 2SS 1LE Join Date: Aug 2019 Location: CT Posts: 112	Apologies for the confusion, ladies and gents. arctic rs 52 has the right idea - the power brakes, which work off manifold vacuum, have (or at least had, idk about today) some sort of check valve which allows the power brakes to work in case the engine stalls while driving. In previous cars of mine, I've been able to let my car sit for over a month without losing vacuum out of that check valve - my Camaro only lasts one week. It's a bit of an odd question, I totally agree. I'd just like to know whether I need to bring my car in for warranty service with some experiences from y'all. For those of you who let your camaro sit for more than a week at a time, is your brake pedal rock hard when you go to start the car?

02-29-2020, 03:05 PM	#8
cmfhsu Drives: 2019 2SS 1LE Join Date: Aug 2019 Location: CT Posts: 112	Interesting - thanks for the feedback, arpad_m. Gives me a lot more confidence my car isn't subtly broken in a way I'll have to fight my dealer about. Thank you!

02-29-2020, 07:28 PM	#9
nancygrl 雪の玉 Drives: '22 Z71 RST Silverado Join Date: Feb 2011 Location: South Posts: 3,415	I've had it happen twice, not worried as it's always been after not driving for a week or longer and only during the winter and pedal is normal after starting up.

03-03-2020, 06:26 PM	#12
cmfhsu Drives: 2019 2SS 1LE Join Date: Aug 2019 Location: CT Posts: 112	Thank you all for your responses; I really appreciate it. I seem to remember my Fiesta ST lasting over a month, but I didn't have to press the brakes to start it, so maybe I just never stepped on the brakes before starting the car.

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