this spongy brake problem has got me stumped. my brother bought a used 91 accord and the brakes were a little soft, but we just figured it needed pads or bleeding. Fast forward to now, and we've changed the front pads, rear pads, master cylinder and bled the crap out of the system. The pedal is really firm with key off; but as soon as we turn car on, its spongy again.

I used wd-40 and checked for vacuum leaks with no luck. while changing the pads, we noticed the previous owner had cut the ABS sensor wires on both sides. the bulb is blown in the abs dash light and the abs motor isn't coming on. Does the abs pump have to presurrize the system in order to get firm brakes? do i need the abs sensors in place to get the pump working? any help with this is appreciated. i have a civic but i'm not familiar with this ABS issue.