I have this 93 accord with abs and recently it was leaking from abs modulator. I found the leak and fixed it. I bled the abs modulator then I proceeded to bleed the brakes. The sequence stated in alldata says LR, RF, RR, LF. I did this twice! It gets pressure with engine off but when I start it it goes to the floor no matter how many times I pump it. I checked for leaks and found nothing. I also pumped the brake pedal 15 times with engine off and it holds pressure. Does anybody know what I am doing wrong? Any help appreciated. Thanks

 

Maybe you can try bleeding the brakes first then bleed the ABS modulator. Probably no harm except for wasted fluid, but try bleeding again and then bleed ABS.

 

Thanks jimblake for your reply. I tried bleeding brakes then abs but no luck. I have a feeling it is the master cylinder. Reason I say that because when I start the car the pedal has low pressure but when I pump it several times it gets more pressure but then starts to drop. I was thinking brake booster at first but I tested it according to the procedure given in alldata and found nothing wrong there.

 

Well, there have been a couple times when I have had to bleed again & again before FINALLY getting all the air out. Seemed like there was a bubble that hung out somewhere & took forever to come loose. Got clear fluid for awhile then finally got a handful of bubbles & it was good. Never really figured it out, so it's just a suggestion...?

 

You know what your right. I bled the brakes again and as I was bleeding I seen this big burst of foamy fluid, looks like I had a huge air bubble as well. Now I have some pressure, not perfect but doable. Appears I have to bleed them one more time and should be fine. But thank you so much for your advice, saved me from buying a MC.

 

dont bother bleeding the modulator, follow the sequence and youll get the air out.
i repair rotten brake lines constantly, including to the ABS never do i bleed mid system, go to the end result of hydraulic pressure, the air will get out, if not replace the master cylinder

 

This is strange. Last night I was driving and lost all pressure. The MC was almost empty and the abs reservoir was so full that it was leaking from the cap. How does that happen? Can a bad MC cause this? Or Proportioning valve?

 

To get a better idea on my situation, I bought this car from a guy who attempted to rebuild it but he couldnt finish it So I took it off his hands and finally got it running. The car had been sitting for a long time with the modulator not installed and brake reservoir empty. Im not sure if this helps but this is the last obstacle out of many and before I replace the MC I want your guys take on this before I spend more money and time. Thanks again.

 

One thing you can try is to take the car to a gravel parking lot and make the ABS work you may have a solanoid hanging up try 3 or moor panic stops be careful and good luck!

 

look at your brake booster below the master cylinder for fluid stains. if its even damp replace the master, if its dry then search the system for leaks, they stick out like a sore thumb if you pump the brakes.
sounds to me like the master cylinder is bad.
bench bleed the replacement and likely you wont need to bleed all 4 corners.