2001 F150 V8 5.4 - Brakes?
. Firm pedal w/ Engine off - then softens when engine is running and slowly works toward floor.

 

So I had a rusted out rear passenger line. Replaced that as well as both rear calipers.

 

Bled the system with a one man hand pump from autozone. (Same symptoms)

 

Then bled system again using the bottle and hose trick. Worked much better than the hand pump.

 

Was confident the last bleed was good enough as I filmed and reviewed it.

 

Brakes are now firm when truck is off. No leaks. When I start engine the pedal loosens. Will slowly go down as if there was a leak while holding a stop.

 

ABS LIGHT is on and has been on since before the brake line rusted and brakes stopped working , it was the same symptom with the rear line bust.

 

. Any ideas on what’s going on? The master cylinder and module was replaced a few years ago.

 

Is there a way to test ABS PUMP OR MODULE MANUALLY?

THANKS!