Have had my car for about 3 years now and I have had this problem ever since.
NO ABS EVER!
I have replaced over time…Pads have been replaced (perfectly worn), calipers are working properly (all greased and free moving), rotors are replaced, lines are good, fluid is new, system has been bleed. There is also NOTHING leaking from anywhere in the braking system.
So the issue is…and yes, I did a search and found a little helpful info, but not a direct answer to what I’m trying to figure out.
My pedal feels nice and firm on that first push till I come to a stop, but if I am holding it down (while on any type incline) I will eventually start to roll backwards and I have push the pedal down further to catch again. SOMETIMES the first push will be really soft and go down to the floor, but not often, usually only when it’s really hot outside is when it gets the worst.
This sounds like the master with bad gaskets inside (since nothing is leaking), but how I pinpoint if it is master cylinder or booster ?
I am really looking for the “this is exactly what i was going through” type of response and how you fixed it. haha
and don’t get me wrong, the car is totally drive-able and I don’t feel unsafe by any means. It’s really just the fact that if I’m not paying attention… I don’t want to roll into someone cause my brakes don’t hold pressure. So with that…which part affects the system holding pressure while stopped…
incorrect. the booster adds vacuum assist to the pedal, ultimately. the symptoms of a booster going bad are a solid pedal/more pedal effort, with loss of brake holding. sometimes, you may hear hissing in the cabin, as this is where air is pulled for assist. you can easily test the booster by applying the brake with engine off. with pedal applied, start the vehicle. the pedal should drop. if it doesn’t the booster is not pulling vacuum.
if there’s no external leaks and you’re absolutely positive all air is bled, it’s gonna be a seal(s) in the master cylinder. there are rebuild kits available, but for what it’s worth, i would just throw in a rebuilt unit. be sure to bench bleed first, then bleed the lines at the master cylinder as well. this way, you shouldn’t need to bleed at all 4 corners
i just went ahead and had my master cylinder replaced…no more sinking to the floor…try the master cylinder first…local advance had it for $45 +$20 core charge
[QUOTE=welfare;2243500]incorrect. the booster adds vacuum assist to the pedal, ultimately. the symptoms of a booster going bad are a solid pedal/more pedal effort, with loss of brake holding. sometimes, you may hear hissing in the cabin, as this is where air is pulled for assist. you can easily test the booster by applying the brake with engine off. with pedal applied, start the vehicle. the pedal should drop. if it doesn’t the booster is not pulling vacuum.
if there’s no external leaks and you’re absolutely positive all air is bled, it’s gonna be a seal(s) in the master cylinder. there are rebuild kits available, but for what it’s worth, i would just throw in a rebuilt unit. be sure to bench bleed first, then bleed the lines at the master cylinder as well. this way, you shouldn’t need to bleed at all 4 corners[/QUOTE]