Brake pedal, low!
02-04-2008, 08:36 PM
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Brake pedal, low!
I know honda accords brake pedal tend to be low. But when im at a stop light, the brake drops then a 15 seconds later it drops again to the point i feel like im not really brakeing but just holding the car in place. I got the breaks checked out i was told they were new. Then the mechanic said my Master Cylinder seals were blown but when i see the MC it looks fine. Guys wanted to charge me 700 dollars to do it. LOL
02-07-2008, 11:52 PM
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Re: Brake pedal, low! (dirtycolombian)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dirtycolombian »</TD></TR><TR><TD CLASS="quote">I know honda accords brake pedal tend to be low. But when im at a stop light, the brake drops then a 15 seconds later it drops again to the point i feel like im not really brakeing but just holding the car in place. I got the breaks checked out i was told they were new. Then the mechanic said my Master Cylinder seals were blown but when i see the MC it looks fine. Guys wanted to charge me 700 dollars to do it. LOL</TD></TR></TABLE>
My car has the same problem (I must get around to fixing it!).
The problem is in the master cylinder. The MC is in effect two cylinders in one, one cylinder for the front brakes and one for the rear (one in front of the other). When the MC gets a bit long in the tooth pressure from one cylinder can leak past it's seal into the other cylinder or into the reseviour.
The MC is leaking internally, but not externally, so you see no signs of leakage and don't lose any fluid as leaked fluid ends up back in the reseviour. Sometimes the symptom will be evident and other times not, on my car the pedal tends to sink sometimes on hot days but is always firm on cooler days(?).
It really is something that does need to be addressed urgently as a matter of safety, because pressure is leaking from one cylinder the pressure in that cylinder won't be high enough. This will affect front to rear brake bias which can have a substantial adverse affect on braking performance, and may cause premature brake lock up at either the front or rear (not sure which end), which could cause loss of control (i.e. massive understeer or oversteer under brakes).
$700 does sound at least a bit steep to supply and fit a new MC, and bleed the brakes. Here in Australia new Accord MCs are around AUD$180 or so.
The pedal should be quite firm with little free play with a braking system in good condition, if yours typically isn't (before you had that sinking feeling) then the brakes probably need attention (bleeding most likely, but could also be a soft rubber hose, causing the hose to bulge under pressure, not good as it may burst).
My car has the same problem (I must get around to fixing it!).
The problem is in the master cylinder. The MC is in effect two cylinders in one, one cylinder for the front brakes and one for the rear (one in front of the other). When the MC gets a bit long in the tooth pressure from one cylinder can leak past it's seal into the other cylinder or into the reseviour.
The MC is leaking internally, but not externally, so you see no signs of leakage and don't lose any fluid as leaked fluid ends up back in the reseviour. Sometimes the symptom will be evident and other times not, on my car the pedal tends to sink sometimes on hot days but is always firm on cooler days(?).
It really is something that does need to be addressed urgently as a matter of safety, because pressure is leaking from one cylinder the pressure in that cylinder won't be high enough. This will affect front to rear brake bias which can have a substantial adverse affect on braking performance, and may cause premature brake lock up at either the front or rear (not sure which end), which could cause loss of control (i.e. massive understeer or oversteer under brakes).
$700 does sound at least a bit steep to supply and fit a new MC, and bleed the brakes. Here in Australia new Accord MCs are around AUD$180 or so.
The pedal should be quite firm with little free play with a braking system in good condition, if yours typically isn't (before you had that sinking feeling) then the brakes probably need attention (bleeding most likely, but could also be a soft rubber hose, causing the hose to bulge under pressure, not good as it may burst).
02-08-2008, 12:51 AM
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Re: Brake pedal, low! (johnlear)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by johnlear »</TD></TR><TR><TD CLASS="quote">
My car has the same problem (I must get around to fixing it!).
The problem is in the master cylinder. The MC is in effect two cylinders in one, one cylinder for the front brakes and one for the rear (one in front of the other). When the MC gets a bit long in the tooth pressure from one cylinder can leak past it's seal into the other cylinder or into the reseviour.
The MC is leaking internally, but not externally, so you see no signs of leakage and don't lose any fluid as leaked fluid ends up back in the reseviour. Sometimes the symptom will be evident and other times not, on my car the pedal tends to sink sometimes on hot days but is always firm on cooler days(?).
It really is something that does need to be addressed urgently as a matter of safety, because pressure is leaking from one cylinder the pressure in that cylinder won't be high enough. This will affect front to rear brake bias which can have a substantial adverse affect on braking performance, and may cause premature brake lock up at either the front or rear (not sure which end), which could cause loss of control (i.e. massive understeer or oversteer under brakes).
$700 does sound at least a bit steep to supply and fit a new MC, and bleed the brakes. Here in Australia new Accord MCs are around AUD$180 or so.
The pedal should be quite firm with little free play with a braking system in good condition, if yours typically isn't (before you had that sinking feeling) then the brakes probably need attention (bleeding most likely, but could also be a soft rubber hose, causing the hose to bulge under pressure, not good as it may burst).
</TD></TR></TABLE>
what?! your all over the place man. your right that a bad mastercylinder can not be visually seen. but whats all this non-sense about brake bias and premature lock up? the m/c doesnt control your brake bias, nor will it cause your wheels to lock, because once the master cylinder starts to go bad, your just losing brake pressure, no brake pressure = no force to stop wheels = no chance of lock up.
to the OP, what your describing is definately your MC, even your mech said so. so go and replace it asap! its dangerous.
My car has the same problem (I must get around to fixing it!).
The problem is in the master cylinder. The MC is in effect two cylinders in one, one cylinder for the front brakes and one for the rear (one in front of the other). When the MC gets a bit long in the tooth pressure from one cylinder can leak past it's seal into the other cylinder or into the reseviour.
The MC is leaking internally, but not externally, so you see no signs of leakage and don't lose any fluid as leaked fluid ends up back in the reseviour. Sometimes the symptom will be evident and other times not, on my car the pedal tends to sink sometimes on hot days but is always firm on cooler days(?).
It really is something that does need to be addressed urgently as a matter of safety, because pressure is leaking from one cylinder the pressure in that cylinder won't be high enough. This will affect front to rear brake bias which can have a substantial adverse affect on braking performance, and may cause premature brake lock up at either the front or rear (not sure which end), which could cause loss of control (i.e. massive understeer or oversteer under brakes).
$700 does sound at least a bit steep to supply and fit a new MC, and bleed the brakes. Here in Australia new Accord MCs are around AUD$180 or so.
The pedal should be quite firm with little free play with a braking system in good condition, if yours typically isn't (before you had that sinking feeling) then the brakes probably need attention (bleeding most likely, but could also be a soft rubber hose, causing the hose to bulge under pressure, not good as it may burst).
</TD></TR></TABLE>
what?! your all over the place man. your right that a bad mastercylinder can not be visually seen. but whats all this non-sense about brake bias and premature lock up? the m/c doesnt control your brake bias, nor will it cause your wheels to lock, because once the master cylinder starts to go bad, your just losing brake pressure, no brake pressure = no force to stop wheels = no chance of lock up.
to the OP, what your describing is definately your MC, even your mech said so. so go and replace it asap! its dangerous.
02-08-2008, 03:22 PM
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Re: Brake pedal, low! (pos_cd5)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pos_cd5 »</TD></TR><TR><TD CLASS="quote">
what?! your all over the place man. your right that a bad mastercylinder can not be visually seen. but whats all this non-sense about brake bias and premature lock up? the m/c doesnt control your brake bias, nor will it cause your wheels to lock, because once the master cylinder starts to go bad, your just losing brake pressure, no brake pressure = no force to stop wheels = no chance of lock up.
.</TD></TR></TABLE>
Sorry, you're correct. The car will have a diagonally split system, I was absent mindedly thinking of a front / rear split system where two seperate master cylinders are used, (as I used to have on an old racing car I had, and on karts with two front brakes as well as a single rear axle brake).
On a diagonally split system if you lose pressure in one circuit then my understanding is that you would lose braking effectiveness on one front brake and the diagonally opposite rear brake, and could still be in danger of premature lock up of a wheel in the diagonal circuit with the higher brake line pressure when braking hard, especially in slippery conditions.
Either way it's seriously unsafe in an emergency, I must fix mine! Problem is that it's easy to ignore if the problem is intermittent...
what?! your all over the place man. your right that a bad mastercylinder can not be visually seen. but whats all this non-sense about brake bias and premature lock up? the m/c doesnt control your brake bias, nor will it cause your wheels to lock, because once the master cylinder starts to go bad, your just losing brake pressure, no brake pressure = no force to stop wheels = no chance of lock up.
.</TD></TR></TABLE>
Sorry, you're correct. The car will have a diagonally split system, I was absent mindedly thinking of a front / rear split system where two seperate master cylinders are used, (as I used to have on an old racing car I had, and on karts with two front brakes as well as a single rear axle brake).
On a diagonally split system if you lose pressure in one circuit then my understanding is that you would lose braking effectiveness on one front brake and the diagonally opposite rear brake, and could still be in danger of premature lock up of a wheel in the diagonal circuit with the higher brake line pressure when braking hard, especially in slippery conditions.
Either way it's seriously unsafe in an emergency, I must fix mine! Problem is that it's easy to ignore if the problem is intermittent...
02-09-2008, 12:49 AM
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Re: Brake pedal, low! (johnlear)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by johnlear »</TD></TR><TR><TD CLASS="quote">
Either way it's seriously unsafe in an emergency, I must fix mine! Problem is that it's easy to ignore if the problem is intermittent...
</TD></TR></TABLE>
same here, mine was bad all the time, but would only be a real problem intermittently. until one day i was sitting in traffic with my foot on brake pedal. than my car started inching forward, and i pushed it to the floor as hard as i can and it wouldnt stop. had to pull the e-brake to keep from rear ending the car in front of me. needless to say i got a new one from honda and had it installed by the end of the night.
Either way it's seriously unsafe in an emergency, I must fix mine! Problem is that it's easy to ignore if the problem is intermittent...
</TD></TR></TABLE>
same here, mine was bad all the time, but would only be a real problem intermittently. until one day i was sitting in traffic with my foot on brake pedal. than my car started inching forward, and i pushed it to the floor as hard as i can and it wouldnt stop. had to pull the e-brake to keep from rear ending the car in front of me. needless to say i got a new one from honda and had it installed by the end of the night.
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02-09-2008, 02:40 AM
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Re: Brake pedal, low! (pos_cd5)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pos_cd5 »</TD></TR><TR><TD CLASS="quote">
same here, mine was bad all the time, but would only be a real problem intermittently. until one day i was sitting in traffic with my foot on brake pedal. than my car started inching forward, and i pushed it to the floor as hard as i can and it wouldnt stop. had to pull the e-brake to keep from rear ending the car in front of me. needless to say i got a new one from honda and had it installed by the end of the night.</TD></TR></TABLE>
At least you weren't going fast. A few weeks ago I was doing a lazy 100kmh and had to unexpectedly brake hard, the pedal went half way to the floor and I was seriously worried for a few of seconds whether the car would pull up. I pushed the pedal very hard and also pumped it a couple of times (to little effect), and it did actually pull up (just), but the braking was way less effective than usual.
Didn't actually lock anything up, but the car became quite directionally unstable. I think if it had been raining I would have locked up a wheel for certain. Brakes have worked almost perfectly since (with only a couple of slight sinkings waiting in traffic, dealt with by a slight pedal pump or two), but it could easily happen again. I think it's new MC time on Monday!
same here, mine was bad all the time, but would only be a real problem intermittently. until one day i was sitting in traffic with my foot on brake pedal. than my car started inching forward, and i pushed it to the floor as hard as i can and it wouldnt stop. had to pull the e-brake to keep from rear ending the car in front of me. needless to say i got a new one from honda and had it installed by the end of the night.</TD></TR></TABLE>
At least you weren't going fast. A few weeks ago I was doing a lazy 100kmh and had to unexpectedly brake hard, the pedal went half way to the floor and I was seriously worried for a few of seconds whether the car would pull up. I pushed the pedal very hard and also pumped it a couple of times (to little effect), and it did actually pull up (just), but the braking was way less effective than usual.
Didn't actually lock anything up, but the car became quite directionally unstable. I think if it had been raining I would have locked up a wheel for certain. Brakes have worked almost perfectly since (with only a couple of slight sinkings waiting in traffic, dealt with by a slight pedal pump or two), but it could easily happen again. I think it's new MC time on Monday!
02-09-2008, 06:40 AM
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Re: Brake pedal, low! (johnlear)
had the same prob with my accord, but i was sitting in my friends driveways and it slowely inched forward, unfortunatly i didnt notice until i bumped his car, o well who cares he drives a cavalier! 
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