Here's the whole story... I have 1996 Honda Accord EX... the ABS light was on and when I pulled the code it said I had a High Pressure Leak in the Modulator. So I bought an ABS unit off Ebay. I install and the ABS light goes away, but the brakes are very spongy. I figure there must be air in the system so I bleed the ABS and the brakes twice. Now the spongyness is gone but if I hold down the brake pedal the pedal will slow go down all the way to the floor. Under noraml braking all is fine, but when I'm stopped at a red light where I have to contiue to press the brake down, the pedal will go all the way down to the floor? What is the problem here, is the ABS unit bad? if it was wouldn't the light be on? Please help... thanks.

 

looks like there is still an air bubble on the line. Bleed the barkes in this order. 1st the right rear 2nd the left rear 3rd the right front and 4th the left front. This will get the air bubble out.

 

might want to look into the brake master cylinder....i assume abs equipped cars have one *Shrug* never drove an abs car before

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by madd &raquo;</TD></TR><TR><TD CLASS="quote">might want to look into the brake master cylinder....i assume abs equipped cars have one *Shrug* never drove an abs car before </TD></TR></TABLE>
Yes, they do and it sounds like his is bad.

 

aldotyper.. I thought the correct or order was RR, LF, RF, LR... can anyone else comment on this...

 

madd & Chiovnidca ... how can I check to see if the brake master cylinder is bad? Is the symptoms I've having typical when a brake master cylinder goes bad?

Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98LS4dr &raquo;</TD></TR><TR><TD CLASS="quote"> Is the symptoms I've having typical when a brake master cylinder goes bad?

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Yes, the sinking to the floor symptom.

 

ive always read that when you bleed your brakes, you start with the furthest point (im guessing from the master cylinder....so i would assume RR RL FR FL)

and yes, sinking to the floor is a good sign its bad heh

 

Is there a slave cylinder? I read in another post that its probably the slave cylinder because if it was the master cylinder ..brake fluid would be leaking everywhere. Is there any truth to this?

 

Sounds like there's still air in there. Make sure the ABS sensor is clean, sometimes dort can make it read wrong.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98LS4dr &raquo;</TD></TR><TR><TD CLASS="quote">Is there a slave cylinder? I read in another post that its probably the slave cylinder because if it was the master cylinder ..brake fluid would be leaking everywhere. Is there any truth to this?</TD></TR></TABLE>

The clutch has a slave, not the brakes. In a bad master cylinder the fluid squishes past the gaskets on the pushrod thereby lowering the pressure available to the system. Replace the MC, it's not a big job.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98LS4dr &raquo;</TD></TR><TR><TD CLASS="quote">Is there a slave cylinder? I read in another post that its probably the slave cylinder because if it was the master cylinder ..brake fluid would be leaking everywhere. Is there any truth to this?</TD></TR></TABLE>Other way around... If a caliper was leaking, it has to leak OUT somewhere. The master cylinder is the ONLY place where it can leak back into the reservoir.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by luckydog &raquo;</TD></TR><TR><TD CLASS="quote">The clutch has a slave, not the brakes...</TD></TR></TABLE>Yes the brake system has slave cylinders. Most people call them calipers. Actually, a brake slave cylinder is just the cylinder/piston part of the caliper, not really it's own separate part.

 

Thanks everyone... I'm going to replace the brake master cylinder. I"ll let you guys know if it solves the problem.

 

Anyone have a write up on how to replace the brake master cylinder? I want to know if there's anything special I need to do, or is it as simple as removing the old one and replacing with the new one.

 

Empty the reservoir. Put rags underneath the MC to catch the fluid drips. Use flare wrenches so you don't round off the flare nuts on the brake tubes. 2 brake tubes, & 2 mounting nuts. I've got a GSR & it helped to remove the shock-tower brace.

Carefully compare the length of piston-rod sticking out of the MC. If it doesn't match, you have to adjust the pushrod down at the pedal. Mine matched, so I didn't have to do this...

Bench-bleeding:
Find some tubing that fits into the holes where the brake tubes go. Fill the reservoir & loop those tubes up & into the reservoir. Pump the MC piston rod. You'll be pumping fluid thru the MC, out the tubes, back into the reservoir. Keep pumping until there's no more bubbles. This saves you bleeding time later.

Install - 2 mounting nuts & 2 tubes.

Bleed the brakes. If you didn't bench-bleed the MC, you'll have to bleed a LOT of fluid thru the system before all the air is gone.

 

Thanks for the write up JimBlake. Can you elaborate more on adjusting the piston-rod? I'm not really sure what you mean by it.

Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98LS4dr &raquo;</TD></TR><TR><TD CLASS="quote">... adjusting the piston-rod? I'm not really sure what you mean by it.</TD></TR></TABLE>I'm not really sure either, since I didn't have to.

There's a tool that you put up against the back of the MC, & adjust it so it just touches the piston rod. Then you put the other end of that tool into the booster, & adjust the push-rod down on the pedal, so it just about touches again. Hard to explain, but I think you'll probably find that your old & new MC's will match each other like mine did.

 

you have to bleed it the brakes in a Z fromation RR, RL, FR, FL

 

Okay.. I just picked up the brake master cylinder from dealer. They charge me $135 for it.... Should I just get one from Autozone or something or should I go with the dealer one? I'm installing this weekend... I'll let you guys know.

 

just an fyi, i dont know if its the same for honda, but on my buddys integra with abs, we bled the damn brakes 20 times, and it was still mushy. called a buddy at acura and he said you had to turn the key to on position and let abs light come on, then bleed. after that it was fine.