Still having low brakes pedal

With brake lines clamped off on Drives side I have great brake. Remove clamp from either line front or back brakes pedal goes low to floor. I've done a complete overhaul trying to fix this problem on all 4 brakes

 

By "full overhaul" I assume you did a full replacement on the fluid..?

 

Yes full fluid replace. 5 or 6 times over

 

Misadjusted rear drums will cause poor pedal.

 

How did you bleed the lines?

 

I've tried just about everything from free bleeding to having someone pump them I even tried with a vacuum pump thr jar on bleeders. Key on, key off. Abs hooked up abs unhooked

 

Ive never experienced this personally on these trucks, but as I understand it, once there is air in the line it can be hard to get it all out because of the abs system. Ive flushed the systems out before, but not with air in the line. Older systems were quite easy to bleed all the air out.

 

So true. Thanks