On Mar 25, 5:49*pm, Mark Rand wrote:
...
I'm confused here. Why do you lot have two axle vehicles with the brakes split
front/rear? Why aren't they split diagonally?

How do you control a vehicle, braking in a corner, if you've lost either the
front or rear anchors?

Expired minds need to know...

Mark Rand

The rear axle load in a pickup varies considerably, the front stays
more constant. Braking pressure that slows down the loaded truck
moderately can lock up the rears when it's empty. On my 91 only the
rear circuit has ABS which senses the average rear wheel speed at the
differential ring gear. A diagonal circuit would require two separate
controller channels, brake line solenoid valves and individual wheel
sensors.

It isn't as good as later ones but I've tested it HARD on ice and it
works pretty well to keep the truck pointed straight. The previous
version was simply a weight switch that detected when the bed was
light.

I was a test engineer on the 1975 version of ABS for big trucks, the
industry's first attempt at mass producing reliable safety-critical
electronics. They all failed miserably, so badly that Congress
repealed the truck stopping distance requirement. However the young
engineers hired for that project (and emissions controls) learned
fast. Previously the only electronic item in a car had been the radio.

jsw