as far as i know master cylinder on my lude is bad right now and i also have ABS lighs on when rolling , i was thinking if master cylinder affect ABS lights to pop out on panel?? i hope so ....anyone ??pls help

 

how do u know ur MC is bad? give us all the info you have including symptoms and stuff u see/smell.. then we can help u by telling you what we(the prelude community) have experienced before w/ similar problems.

 

If the master cylinder was bad, your brake light would go on. Try to pull your codes

 

hey, check to see if your parking brake is all the way off and that the switch hasnt gone bad. This will cause the problem you speak off

 

i know what he is talking about i had the same problem, the abs lights turns on. the brake master cylinder can cause the light to go on if it is bad. do you feel the brake pedal slowly start to fade in? if so then you have bad brake master. but it can be other things too

 

ok this is 94 prelude Si and yes the brake faded while pushing it, and i know that only master cylinder that pushes the fluid to the caliper if that one has bad o rings it will fade, but my question is does it affect the ABS system fault i hope thats the problem... as far as other light nothing everything is working fine except that ABS thing and my MC fading....thanx guyz for helping i hope i get this thing done and will help other owners in the future...take care

 

Yeah i have a 94 prelude si too, change the brake master cylinder that is mostly your bad part, it will most likely fix the problem. yes it does affect the abs light.

 

a bad master cylinder makes the pedal sink to the floor, can someone explain how it could turn the ABS light on cuz im pretty damn sure thats impossible.

if it only comes on when you start rolling, its almost for sure a wheel speed sensor problem

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheWalrus &raquo;</TD></TR><TR><TD CLASS="quote">a bad master cylinder makes the pedal sink to the floor, can someone explain how it could turn the ABS light on cuz im pretty damn sure thats impossible.

if it only comes on when you start rolling, its almost for sure a wheel speed sensor problem</TD></TR></TABLE>

Often faults in the braking system will cause the ABS system to override to prevent failure.

 

i let evryone know as soon i change that MC i hope thats about it...i also clean those speed sensors 4 of them very easy... for those who have speed sensor problem its realy easy to clean ,...thanx guyz...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ~sp33~ &raquo;</TD></TR><TR><TD CLASS="quote">

Often faults in the braking system will cause the ABS system to override to prevent failure.</TD></TR></TABLE>

i disagree...the regular brake system is all hydraulic and the fluid does go through the abs system so it can be modulated if a wheel starts to lock up. But the abs system does nothing until a wheel speed sensor says a wheel is going slower than the others, thats the only way it knows theres a problem.

the master cylinder only controls fluid pressure to the calipers, the abs system has nothing to do with fluid pressure. i work at a shop and fix brake lines, MCs and other fluid pressure problems, never seen it turn on an abs light even when the pedal goes straight to the floor

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheWalrus &raquo;</TD></TR><TR><TD CLASS="quote">

i disagree...the regular brake system is all hydraulic and the fluid does go through the abs system so it can be modulated if a wheel starts to lock up. But the abs system does nothing until a wheel speed sensor says a wheel is going slower than the others, thats the only way it knows theres a problem.

the master cylinder only controls fluid pressure to the calipers, the abs system has nothing to do with fluid pressure. i work at a shop and fix brake lines, MCs and other fluid pressure problems, never seen it turn on an abs light even when the pedal goes straight to the floor </TD></TR></TABLE>

I thought ABS modulates the pressure? And if a wheel for example would stop rotating (jam's) and the ABS couldn't get it moving again, doesn't the system suspect a faulty sensor and overide? Not arguing, just trying to learn something.

 

i cleaned the speed sensors i have test the car coz im buzy, anyway where is the relay located anyway???

 

ok i change the MC and the brake pedal felt really good no more fading but as soon as i hit the brake ABS light came out now its either modulator, relay, or really bad speed sensor...ill give it a try on weekend again to change the relay...hope this time works...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ~sp33~ &raquo;</TD></TR><TR><TD CLASS="quote">

I thought ABS modulates the pressure? And if a wheel for example would stop rotating (jam's) and the ABS couldn't get it moving again, doesn't the system suspect a faulty sensor and overide? Not arguing, just trying to learn something.</TD></TR></TABLE>

yes abs modulates the pressure (basically pumps the pedal for you) if it sees a wheel stop and skid while the others keep going. the whole abs system will stop working if theres no signal from 1 wheel speed sensor

logicmobile do you know how to pull the abs codes?? its the same as checking the check engine code on 4th gens...therell be a 2sec pause, then itll flash X amount of times, then a 1 sec pause, and itll flash another X amount of times. the first X = main code, second X = sub code

for a wheel speed sensor, itll flash 4 times for the main code...then pause 1sec, then for subcode...1flash=right front, 2=left front, 4=right rear, 8=left rear

 

iima check that so i wont be guessing ,, anyway it should be located under the glove box right? the jumper to see the code.?

 

no, its on the driver's side half of the center console, just right of the gas pedal, just reach behind the center console youll find it. its a blue plug not connected to anything, but its got a blue plastic piece sticking out of it. unplug it from the plastic piece and connect the pins with a cotter pin or paper clip, then turn the key to the on position and count the blinks from the abs light

 

thanx, i have a 94 honda prelude si and was wondering what that plug was for!!! now i know

 

anyway the story continue about ABS popping on during rolling after couple of second...so i change the Mc and test it and ABS light pop out again so i said ok...imma end up checking the code....and also its time to smog and so i went to smog station and i believe the guy so it but i didnt think he'll make something out of it so smog test is done and we went to drive to DMV its about 4 miles from that time ABS didnt pop out for some reason....i dunno what he did , i just saw he plug in something in the engine compartment but i dunno if that part of the test,,,,so yea i will check soon again as soon as i drive the car let you know guyz the update ...if no ABS light goes off imma go back to the smog station and ask the guy what did he do to the car...