The Kelsey Hayes 4WAL systems used on many GM pickups are very unique in their operation and can be very expensive to fix. This course covers differences in the system over the years and explains the systems in great detail. A working Kelsey Hayes system will be used in class and be used for demonstration. The student will also be shown how to disassemble a HCU in order to better understand the operation of the system and learn the details of proper brake bleeding procedures. A detailed student manual is included.