Hey all,
I drove my turbo 2.4 to work today... I was coming off a green light and sped up a little bit, the next light is around a small curve.. as Im approaching it turns yellow.. I go to stop for the light & the brake pedal pushed in w/ little resistance...
It felt like it was at the bottom, but the car wasn't braking very well.. I released and braked again hoping to build pressure, but I didnt have enough time to let go again... I ended up just holding the pedal down as the car gradually slowed down... It was a little scary
The next light was totally fine & the 15 lights after that, but Im very weary now about the car not stopping...
I tested it again around the corner from my work.. Started getting on the car a little bit, then trying to stop immediately and the pedal kinda had the same feeling.. I pumped it a few times and it came back to normal... My brakes are good and work 99% of the time, but it seems like when I immediately come out of boost, it doesnt have the pressure in the pedal..
I am running the hard booster line from the brake booster to the fuel rail area, then it switches over to a rubber coolant line & runs to the throttle body..
Anybody else have an issue w/ their brakes acting wierd w/ a boosted car?? Im wondering if the12"-16" of rubber hose is expanding??
Thanks!
_marc
brake pedal should not push in with little resistance reguardless of booster vacuum issues. if the booster or vacuum to the booster fails then the pedal is hard with no assist. you just have to push the pedal harder to stop. the pedal intermittently going all the way to the floor with little effort and a loss of braking is most likely your master cylinder failing. if you have to pump your brake pedal to get your brake pressure back then the master cylinder is leaking internally. replace it.
Gotcha...
So, I guess if the booster line was an issue, it would just be hard to press-not hitting the floor.. The opposite of my problem...
Come to think about it, I had an issue last summer sometime when the booster line popped off the firewall and I had to stand on the brake to keep it from rolling forward in DRIVE....
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I guess I'll pick up a new master cylinder, today could have been a very bad day if there was someone in front of me @ the light. Now, I just gotta get it home. 20 miles !!
that is correct. without assist you will need to apply more foot pressure to the pedal to stop. the pedal should not go to the floor with little pedal effort. little pedal effort is because there is a loss of hydraulic fluid pressure. this is caused by a leaking brake component weather it is visible or internally like a master cylinder. the seals in the master cylinder are worn which causes a small internal leak. this is why the pedal gets harder again when you pump it or it slowly goes to the floor when you are at a stop. replace it. ther cheap. the hardest part of the replacement is the bleeding. make sure you bench bleed the master cylinder before you install it. it will save you ours of frustration..
or he could have a vacuum leak mine use to do the same
RIP Cpl Derek Kerns And Cpl Robby Reyes
24th MEU VMM-261 (REIN) V22 Crewchiefs
11 April 2012 Morocco (African Lion)
a vacuum leak will not affect hydraulic pressure. a vacuum leak will only cause a loos or a lack of brake assist.
Well.. I did make it home last night..
I made sure my brakes were functioning before approaching any stops & downshifted to help slow the car down...
On the way home, the pedal went soft twice, all the other times- nice and firm...
It not a daily driver and is being put away for winter fairly soon, so I will replace that master cylinder when I get a chance & we'll see how that goes..
Thanks for the info !!
your welcome. good idea to store it as you dont want to drive it like that. losing brakes is one hell of a scarey feeling.
I also have this problem but since it happened worse at the track I was leaning towards old fluid and extra heat. Perhaps I should replace my master cylinder as well.
I had the same problem. I replaced the master cylinder, no more soft pedal and scary stops. However, you are supposed to use a Tech II scan tool to relieve the ABS motor tension in the gears, otherwise injury can occur (in accordance with the GM service manual). You could probably get it done at a dealership if you don't know somebody with one, for 20 bucks or so. You won't have ABS after they do it though, drive it home and fix it.
ck the wheel cyls in the rear for leaks or a brake line thats leaking food for thought
