making brake pedal go stiff

HeLLz aNgeL · 12-23-2006, 12:04 AM

ok, i was trying some wierd stuff out on my auto ex ...

anyone tried this ??? put your car in park, turn off the ignition, but let the key remain in there ... press the shifter clicker (the thingy you press before shifting gears) on the auto transmission a couple of times .... you hear those nice clicky sounds .. now right after pressing that put your foot on the brake pedal a couple of times ... now press the clicky things a couple of times and put your foot on the brake again.... do that again .. your brake pedal should be stiff as hell .... when you turn the ignition on, it returns back to normal position ...

now im a newby at this, so was just wondering if anyone had any idea why this happened ???

honda93 · 12-23-2006, 12:19 AM

One has nothing to do with the other.

ALL modern braking systems built in the last 25 years (or more) have a vacuum-based (air pressure) brake booster designed to lessen the force a person must physically exert in order to stop the car. So instead of it taking say, 50 lbs. of leg force to depress the brake pedal and maintain that force until the car stops, it may take 20 lbs. This cuts down on driver fatigue and enables a wider variety of driver to safely and comfortably operate the car for any period of time.

The brake pedal got stiff because you basically "used up" any remaining vacuum assist in that brake booster and what you felt was the true force needed to operate those brakes.

Try doing that next time on a slanted driveway while the car is off and in neutral. See for yourself how much longer and more difficult it is to modulate (control) those brakes compared to when the car is running and able to help you.

Anthony "Mario" Crea
NNJR-SCCA

dannn · 12-23-2006, 12:28 AM

that is normal.
the vaccum booster stores about 3-5 pumps of vaccum after the engine turns off.

the engine can only show vaccum when its running so that is why you feel the pedal get hard.

bizzybearfigiblue · 12-23-2006, 12:30 AM

repped both of u.....thanx for saving me the time to type up the explanation

honda93 · 12-23-2006, 12:35 AM

Thanks...

Anthony "Mario" Crea
NNJR-SCCA

12-23-2006, 12:04 AM	#1 (permalink)
HeLLz aNgeL Senior Member Join Date: Sep 2006 Posts: 105 iTrader: 0 / 0%	making brake pedal go stiff ok, i was trying some wierd stuff out on my auto ex ... anyone tried this ??? put your car in park, turn off the ignition, but let the key remain in there ... press the shifter clicker (the thingy you press before shifting gears) on the auto transmission a couple of times .... you hear those nice clicky sounds .. now right after pressing that put your foot on the brake pedal a couple of times ... now press the clicky things a couple of times and put your foot on the brake again.... do that again .. your brake pedal should be stiff as hell .... when you turn the ignition on, it returns back to normal position ... now im a newby at this, so was just wondering if anyone had any idea why this happened ???

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Vibration in clutch pedal?	SonicK20Z	Mechanical Problems & Technical Chat	9	09-10-2007 12:04 AM
Minor Brake Upgrading	604_ep3	Suspension and Brakes	5	02-26-2007 01:13 AM
Brakes (06' Si) Parts-list:	Torredo	Suspension and Brakes	3	12-07-2006 02:59 AM
brake - heads up.	sickyute	Suspension and Brakes	19	11-23-2006 03:37 PM

12-23-2006, 12:19 AM	#2 (permalink)
honda93 Senior Member Join Date: Oct 2005 Location: Property Tax Hell... NJ Age: 34 Posts: 1,011 iTrader: 2 / 100%	One has nothing to do with the other. ALL modern braking systems built in the last 25 years (or more) have a vacuum-based (air pressure) brake booster designed to lessen the force a person must physically exert in order to stop the car. So instead of it taking say, 50 lbs. of leg force to depress the brake pedal and maintain that force until the car stops, it may take 20 lbs. This cuts down on driver fatigue and enables a wider variety of driver to safely and comfortably operate the car for any period of time. The brake pedal got stiff because you basically "used up" any remaining vacuum assist in that brake booster and what you felt was the true force needed to operate those brakes. Try doing that next time on a slanted driveway while the car is off and in neutral. See for yourself how much longer and more difficult it is to modulate (control) those brakes compared to when the car is running and able to help you. Anthony "Mario" Crea NNJR-SCCA

12-23-2006, 12:28 AM	#3 (permalink)
dannn Senior Member Join Date: Nov 2006 Posts: 516 iTrader: 0 / 0%	that is normal. the vaccum booster stores about 3-5 pumps of vaccum after the engine turns off. the engine can only show vaccum when its running so that is why you feel the pedal get hard.

12-23-2006, 12:30 AM	#4 (permalink)
bizzybearfigiblue Senior Member Member Join Date: Apr 2006 Posts: 18,279 iTrader: 4 / 100%	repped both of u.....thanx for saving me the time to type up the explanation

12-23-2006, 12:35 AM	#5 (permalink)
honda93 Senior Member Join Date: Oct 2005 Location: Property Tax Hell... NJ Age: 34 Posts: 1,011 iTrader: 2 / 100%	Thanks... Anthony "Mario" Crea NNJR-SCCA