miro_gt

I had to stop hard (110MPH to 60MPH) , and my front wheels locked up, but my rear ones didn't. Since then, my brake pedal sinks, and I can't stop ... I've bleeded the brakes twice.

what's the problem ?

The car is 95 Civic EX Turbo, with ABS and stock brake system

10x

Throwdown

iTrader: (2)

did you check the master for leaks?? are you losing fluid?? check all the lines?

miro_gt

no brake fluid leaks - the can up top stays full

pdiggitydogg

Are you running rear drums? Its a lot more difficult to lock the rear wheels, than the front, even with disc. I honestly can say Ive never seen it, off-track.

I would flush the entire system, using new fluid.
You probably have an air bubble in there somewhere.
If flushing doesnt work...come back (?)

miro_gt

rear ones are drums

I've bleeded twice, but at the wheels only. I don't know where else to bleed from. It's all new fluid in the lines now, DOT 3

the system worked fine, but after a hard stop it would not work anymore. I think there's a bypass valve (prop valve) somewhere that may have gotten stuck open or something, so I'm loosing all the fluid pressure.

is there a way to reset the ABS computer ? (I'm not sure where it is located though). I did reset the ECU, but that didn't help.

pdiggitydogg

"bled"

Did you do it in the correct order? Did you make sure the MC didnt get dry when you did it?
You only bleed it at the wheels, unless you change the MC.
If its drums, you dont have ABS. Resetting the ECU wont do anything.

schardbody

you blew the seal in the master cylinder, get a new one.

the HARD stop most likely free-ed all the gunk from around the seal inside your master cylinder.

do this: using vise grips with a rag clamp off all 4 brake lines at one time, see how the pedal feels then, if its good then you have a stuck slide, cocked brake pad, or air at one of the wheels. while you hold the pedal get a buddy to remove the clamps one at a time, when you get to the problem wheel the pedal will start going down, check everything at that wheel.

if the pedal still sinks with the lines clamped off you have a faulty master cylinder.

miro_gt

I'm not sure if that's gonna help, but when the brake pedal sinks all the way down while driving (still no brakes), it reaches kinda like a limiter but I can push it just a bit more, and that's when my front right wheel locks up ..

also, when we were bleeding the brakes (the car is off), the pedal would harden (pressure-wise, not due to the brake booster) but would still sink little by little.

- did you mean to replace the seal in the master cylinder, or the whole master cylinder ? If it's not an ABS problem, then a MC problem would explain the symptones

10x for the help

pdiggitydogg

You shouldnt be driving this car...

Alright...youre building pressure, but youre not keeping it. Im going to say MC now too.

schardbody

the pressure will build with the car off only because of no vacuum assist.

that "limiter" you feel is the master cylinder piston bottoming out in the bore, the pedal will sink just a bit more before it hits the floor and stops.

i wouldnt rule out other possible causes yet. NORMALLY, when the master is going bad you wont build enough pressure to lock ANY wheel up. sounds like you might have blown the wheel cylinders out in the rear. pull the drums off and take a look before assuming anything. and i would also clamp the lines like i said. if you only have one clamp do one wheel at a time, and you can rule out hydraulic problems that way. almost garentee you its a hydraulic pressure lose in the rear system somewhere due to the fact that the front is locking up. most likely right rear if left front is locking up. hope that helps.

miro_gt

thank you

one guy just suggested that I unplug the ABS computer and see what's gonna happen. If nothing changes, then it may be the MC (or a brake piston/s at the wheel/s). If things get better, then it is the ABS system and I'll have to deal with it later.

I'll just have to find where the ABS computer is now

chrisw85

I'm not aware of a 92-95 civic that had rear drums and abs brakes. My 94 ex coupe is abs and has rear discs.


Modified by chrisw85 at 9:04 PM 12/30/2006

sasser43

My dx had drums on the back.

To the OP: If you have rear drums, you dont have ABS

miro_gt

Ah .. ****

I just finished reading 2/3s of the topics that the search yielded for "ABS" ... and it looks like I'm not having an ABS system. However, when I changed my axles, I had to order ABS-compatible axles from NAPA ..

so yeah, I don't see the box with the oringe connectors, and I have (6) total in/outlets on my proportional valve. I'm not sure if I've seen an ABS light, but I guess I'll go down and check. Also, I'll check under the battery to see for an ABS unit .. but I'll probably not find any ..

sorry for my incompetence on the subject..... I'll compensate for that with my turbo knowledge, LOL

chrisw85

only diff between the abs and non-abs axles is the abs ring, you can use abs axles on non-abs vehicles, but you cannot use non-abs axles on abs cars, unless you've disabled abs or dont use it.

miro_gt

Well, I don't have ABS.

So, my brake problem should be the Master Cylinder .. (I don't think it's the rear drum brakes, or the prop.valve)

- remanufactured MC costs 70 bux with the old one returned, or 95 bux and you keep the old one - from Advanced Auto Parts ... I guess I'll be changing that one tomorrow if they have one in stock. .. may check NAPA too ..


Thank You everyone for the help. I'll update after I'm done with that.

Miro

trrbl1bmx

When you "slammed" on brakes you generated ALOT of heat, therefore you probably didn't dissipate as much heat as you needed to, causing your brake fluid to boil. When brake fluid boils it does the same as water and gives off steam, so now you have air in your brake lines at the very least. Since you have kept driving it, you could now have a bad cup seal in the master cylinder, very rarely are you going to mess up and prop. valve. Do as schardbody said and clamp the wheels off and determine EXACTLY where your problem is. You really shouldn't use guess work when working with brakes, a lot of peoples lives are in your hands when you do that. If your not completely sure at where to start take it to a local shop ( on a truck ) and have them check it out.

highroller54

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by p00n &raquo;</TD></TR><TR><TD CLASS="quote">When you "slammed" on brakes you generated ALOT of heat, therefore you probably didn't dissipate as much heat as you needed to, causing your brake fluid to boil. </TD></TR></TABLE>

If brakes were that fragile how would anyone ever drive in the mountains, if the brakes are "locked up" they wont generate any heat.
Go buy a new master if you are 100% sure you have no leaks, bench bled the master, instal and bleed all 4 really well.

Luserkid

Im not saying its Master Cylinder just yet because it seems like no one caught this:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by miro_gt &raquo;</TD></TR><TR><TD CLASS="quote">
also, when we were bleeding the brakes (the car is off), the pedal would harden (pressure-wise, not due to the brake booster) but would still sink little by little.

</TD></TR></TABLE>

Your bleeding the brakes wrong. You have to have the car idling while bleeding brakes or else your just making it worse.

Car idle up in the air (block the front tire).
Start with pass rear and jack that side up, have someone pump 7 times and hold on 7.
Crack open bleeder valve til liquid stops and then close continue until you see a steady stream.
Repeat in this order: Pass rear, driver rear, pass front, driver front.
By the time you get to the driver front alot of air will come out.

Remember to keep a hose on the bleeder screw as well when you crack it open, and never let the MC go dry.

schardbody

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Luserkid &raquo;</TD></TR><TR><TD CLASS="quote">Your bleeding the brakes wrong. You have to have the car idling while bleeding brakes or else your just making it worse.

</TD></TR></TABLE>

and how do you figure that??? the only thing having the vehicle running will do is allow power assist, which isnt needed to bleed the brakes.

Luserkid

Because when you bleed the brakes without the help of the Brake Booster your not pushing the fluid fully to where it needs to go which allows for air to escape to different areas. If your going to do it without the BB then youll need a vac source of some kind to suck out the rest of the fluid/air through the bleeder screw.

highroller54

I do probably 10 brake jobs a week at work and I dont bled the brakes with the car running. I guess my automotive training/schooling has failed me again, I better give up my shop forman job because of my incompetance, stupid ase certification.

schardbody

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Luserkid &raquo;</TD></TR><TR><TD CLASS="quote">Because when you bleed the brakes without the help of the Brake Booster your not pushing the fluid fully to where it needs to go which allows for air to escape to different areas. If your going to do it without the BB then youll need a vac source of some kind to suck out the rest of the fluid/air through the bleeder screw. </TD></TR></TABLE>

so if you dont have vacuum assist while bleeding the brakes where does the air go??? it can only go one way, out. it is EASIER to bleed with it running cuz you dont have to push so hard, but it isnt required.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by highroller54 &raquo;</TD></TR><TR><TD CLASS="quote">I do probably 10 brake jobs a week at work and I dont bled the brakes with the car running. I guess my automotive training/schooling has failed me again, I better give up my shop forman job because of my incompetance, stupid ase certification. </TD></TR></TABLE>

i do about triple that, and also a master tech, damnit, i guess these 8 certifications were for nothing

schardbody

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by p00n &raquo;</TD></TR><TR><TD CLASS="quote">When you "slammed" on brakes you generated ALOT of heat, therefore you probably didn't dissipate as much heat as you needed to, causing your brake fluid to boil. When brake fluid boils it does the same as water and gives off steam, so now you have air in your brake lines at the very least. Since you have kept driving it, you could now have a bad cup seal in the master cylinder, very rarely are you going to mess up and prop. valve. Do as schardbody said and clamp the wheels off and determine EXACTLY where your problem is. You really shouldn't use guess work when working with brakes, a lot of peoples lives are in your hands when you do that. If your not completely sure at where to start take it to a local shop ( on a truck ) and have them check it out.</TD></TR></TABLE>

ashby, you're correct about boiling the brakes, but i havent EVER seen a stock vehicle boil the brakes with one stop unless there is something locked up causing ALOT of heat at that one wheel ie; LF caliper dragging causing the fluid to get hot, then a long hard stop. but just one hard stop shouldnt boil the fluid. in which case bleeding would have solved the problem anyways.

Luserkid

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by highroller54 &raquo;</TD></TR><TR><TD CLASS="quote">I do probably 10 brake jobs a week at work and I dont bled the brakes with the car running. I guess my automotive training/schooling has failed me again, I better give up my shop forman job because of my incompetance, stupid ase certification. </TD></TR></TABLE>

I wont get into how lame and stupid the ASE cert is but that doesnt mean anything to this thread. Everyone has there way of doing things. I do my brakes with the car on. The OP did it with the car off and to me that looks like it didnt work, try with the car on before you go out and spend money on something that might not even help your problem.