Another RABS issue

[Slade]

After searching I can't find the answer I'm looking for. My ABS light has started coming on. When the lights on brakes work fine. When it's off the brake pedals bad with a clinking sound and strange pulsing feeling. I seem to remember a thread that talked about eliminating the sensor in the rear since this system is more trouble than its worth. Any ideas.

 

[LCAM-01XA]

You have a '94, you can't touch that VSS sensor cause you'll lose speedometer and cruise. It seems that for some reason your RABS thinks the rears are locking up during normal braking and so it dumps the line pressure (hence the pulsing pedal poor stopping power), then at some point the brain realizes there's something very wrong and shuts the entire system down which disables the HCU and your brakes start working pretty much like they would on a non-RABS truck. Why that happens tho idk, there are ways to pull codes off the RABS brain and maybe those will help figure out what's going on exactly.