'96 Silverado ABS

[ejazz]

I have a '96 Silverado 4x4 with a V8. The problem I am having is with the ABS system. When braking slowly like pulling up to an intersection, the brake pedal will slowly go down and then the ABS system kicks in and the pedal starts to pulsate. When I pull the 60 amp fuse for the ABS system it takes care of the problem but then the light stays on the dash. I have replaced all shoes, pads, drums and rotors. When the fuse for the ABS is pulled, the brakes work awesome. I would like to keep the ABS. Where do I start, wheel sensors? Thanks.

[Blue Bowtie]

I believe the '96 used a Kelsey-Hayes system. There is no accelerometer, so it's all done with the VSS input and wheel/axle speed sensors. Unless something has been changed the system should operate normally. Changing a transfer case, front wheel hub, brake rotor, PCM, or VSS can affect the EBCM and make the unit think there is a locking wheel. If none of the brakes lock with the ABS disabled we can probably safely presume the brake bias is correct and the brake hardware is working normally.

If there is a mismatch in wheel speed sensor inputs the EBCM should turn on the amber ABS warning lamp just driving down the road without braking. Again, a different rotor, transfer case, or VSS, or a replaced PCM can cause the speed signals to change. If there is no warning light during normal driving, the EBCM is detecting what it interprets as wheel slip. A marginally weak sensor can do this, but usually also sets the code while driving. A poor connection can also do this if the inertial forces of stopping affect a wire harness or connector somewhere.

It may be best to connect an ABS capable scanner and read the codes as a starting point.

[ejazz]

Thank you for the input. I think I will start by removing the sensors and make sure the ends are clean and free of any debris. Yes, no ABS light comes on during normal driving.
Whenever the brakes are applied hard, the problem with the ABS does not occur. It is only when you gradually apply the brakes then the pedal slowly goes down more than normal and the ABS kicks in. Thanks again.