[jumpsoffrock]

Originally Posted by Bob B.

What year is your truck? I ask because around 1975 the DOT briefly required antilock brakes on all new heavy trucks and buses. Needless to say, it was a fiasco, the technology just wasn't there yet for reliable ABS on air brake equipped vehicles. Most operators removed the ABS components and replaced the complicated and failure-prone ABS control valves with standard relay valves. The sensor in your picture looks like an old wheel speed sensor.

That is VERY interesting history! Thank you for that. I'll have to read up on that. Really cool info!

Not sure if he found the year. It was a mystery at one point.