AM stumped by a soft brake pedal and weak brakes. All new hardware at all four corners, new master cylinder and vacuum booster, all hoses good. Bled brakes properly including using a scan tool to activate the ABS pump. NO air in the system.

Any thoughts? BTW, not an amateur with tools, just baffled.

 

Welcome to the forum. Well, I am an amateur now but it sounds like you still have air trapped in there. Also, in those days they used weak accumulators in the BPMV that can bleed off the pedal generated pressure when an isolation/dump valve fails to close. Maybe you can try disconnecting and capping off one of the lines from the master cylinder to isolate the problem to the front vs. rear?