03 Dodge Caravan, had new wheel cyl rear, calipers and hoses and brakes all the way around. 6mos ago, now pedal goes all the way to the floor, so shop put a master cyl worked a week had air in lines put another master cyl same thing once a week has to bleed brakes. Does not loose fluid where is the air coming from!
Are they unhooking the load sensitive proportioning valve from the rear suspension? I assume that they still use them.