2001 e450 sinking brake pedal

[gonecrazyi]

I'm working on a 30ft motor home based on a 2001 e450 van chassis with a v10.

The symptoms are the pedal slowly sinking to the floor. the front brakes easily lock up but the tears don't seem to grab hard. There is plants of pressure and flow at each wheel and I. Getting no air bubbles.

I've replaced the master with a new unit and bled the brakes. I have also replaced the rear calipers and shoes. In lost as to why the pedal still sinks and the rear brakes aren't working correctly.

Any ides would be great. I'm thinking the ABS unit is bad.

 

[Optikalillushun]

Did u bleed the ABS valve? Are the rear rubber lines swelling under pressure? Dont know what else to suggest, used to work on the same platform but in shuttle bus style and never had that issue.

 

[gonecrazyi]

The ABS unit is right under the master. I did bleed it just to rule it out. I forgot I also replace the front runner lines. The back lines still look good.

 

[Optikalillushun]

No idea then, trying to remember if there were any funky things that stuck out in my mind about those chassies.