1995 Nissan Pickup No Brake Pedal
Sometimes following thier specific procedure make the difference. Use gradual, slow pressure and return.
It sounds like either the master cylinder tht was replaced may be defective or possibly air is coming back into the system.
I question the master cylinder for a couple reasons. When you lose a pedal and it hits the floor, the master cylinder can be damaged. Thus the replacement. Re-man masters are not always the most reliable ones. You can check the master by plugging the line recepticles after removing the line from it. The pedal should be hard.
I have had bleed problems where air comes back into the line, but doesn't leak fluid out. Why I don't know, but I just know what happens. We were able to narrow it down to the bad line/wheel sector because it did give air.
I would open the bleeders and see if any bubble come out, next check the adjustment of the brake shoes they could be way out.
Suggested Repair
Bleed in order: left rear, right rear, left front, right front, then the R-ABS actuator, using slow gradual pedal strokes. If the pedal still sinks, plug the master-cylinder outlets to test it; a reman unit may be defective. Also check for air returning at the bleeders and inspect rear shoe adjustment.
Conversation Summary
A 1995 Nissan Pickup has no brake pedal after a brake line and reman master cylinder were replaced and the system was bled repeatedly. The pedal can be pumped up with the engine off but goes soft, and there is no pedal with the engine running, with no visible leaks. The expert advised bleeding the R-ABS actuator in the specified order, testing the master by plugging its outlets, checking for air re-entering the lines, and verifying brake shoe adjustment.
