Hi All,
my 07 accord, has about 140,000 miles. with the engine off, I pump the brakes and the pedal gets hard. When I start the engine, the pedal goes way down, almost to the floor. I have replaced the master cylinder and bled a whole bunch of fluid through the system, all 4 wheel cylinders. The master cylinder has a bunch of green sludge in it, which is why I replaced it. Pedal was spongy before but not this bad. No idea what to do next. I can't find where the check valve is located. Any help greatly appreciated!
Thanks
Redd

 

Don't know much about the 07Accord.
Did you have to do anything to the ABS unit in order to bleed the brakes?
All 4 wheel cylinders? Do you have all four drums?
Or do you have brake calipers in front and drums in the back?
Or is it all disc brakes?
If you have calipers then look at them and check to see if the brake bleeder screw is on top or bottom of brake fluid chamber??
If you have drums in the back then try adjusting them a bit tighter to get rid of the empty space??
Don't forget to inspect brake lines for leaks and brake hoses for bubbling??

 

Thanks! this one has 4 wheel disc brakes. I had replaced the front calipers recently, without any problems, bled out fine and brakes were good. The rear calipers were done about 1 1/2 years ago, similar, braking was fine. Few months ago, there was a bunch of green residue in the master cylinder. I cleaned and flushed but the green residue got worse. I think its something about the fluid level sensor that corrodes. Anyway at this point, all 4 calipers are new, and the master cylinder. I always bled by having someone sit in the car and put pressure on the brake pedal, then I open the caliper bleeder valve until the pedal drops, tighten the bleeder, then repeat. I don't have any access to open the ABS. I read someplace that you need a computer and send a code in to do that. maybe that's the problem?

 

Will check the brake hoses again, thanks haven't done that carefully in a while.

 

A possibility could be the new master cylinder isn't the right one for your vehicle?
Is it aftermarket or Honda OEM?
Don't know.