Christof13T
Junior Member
Swapped in a drw axle in a 96 2500 with the 5.9 diesel. Oem equipped with vacuum pump and vacuum booster. Replaced both sides front rotors, calipers, pads. After bleeding the system the brakes work. The truck stops. The pedal however slowly creeps to the floor with engine running. Brakes hold even at the floor but the symptoms are a little unsettling. I have been back through every bleeding process and combination imaginable. Replaced master cylinder and vacuum booster... Exact same symptoms. Disconnected the rwab valve with no change but an illuminated abs and brake light. Disconnected Batts for a fee minutes cleared the brake lights. Brakes do not fade or give in the slightest while the engine is not turning. The vacuum booster is seeing 25"hg and appears to be retaining vacuum. I'm damn near at a loss here.
Likely culprits:
The nee master cylinder is leaking internally.
The rwab module is hung open allowing bleed off to the accumulator.
The calipers on the new rear axle take much more volume than the cylinders on the old axle did and this is the response from the system doing it's best to supply the demand?
Even if the rwab Doo dad is bleeding off it should run out of space to fill against that spring that the pedal would get firm before it hits the floor right?
Likely culprits:
The nee master cylinder is leaking internally.
The rwab module is hung open allowing bleed off to the accumulator.
The calipers on the new rear axle take much more volume than the cylinders on the old axle did and this is the response from the system doing it's best to supply the demand?
Even if the rwab Doo dad is bleeding off it should run out of space to fill against that spring that the pedal would get firm before it hits the floor right?
