Brakes Locked up on Freightliner While Bobtailing?

On my dads old IH think 2290 model trucks. 60's. Can't remember if my old Fleetstar had it. It was a1970.

 

Edit it was model 190.

 

It probably did... I used to drive a 1974 Mack Dump truck that had it as well.... And it had wigwags for the low air alarm.

 

A vintage Bendix-Westinghouse out of an A-car

 

If the ABS was not working the drive tires will lockup first and slide on top on the road because their is no enough weight to keep them on the road.

I had this happen to me before. Driving bobtailing and hits the brakes hard to stop. Because of bobtailing truck won't stop. So you have to really push hard on the brakes. I'm talking like 60+ PSI if truck had applied brake pressure gauge you can see this. Since only the steer axle brakes are stopping the truck. The drive tires just slide on top on pavement. So the ABS stops them from locking up. When you apply lots pressure to the front brakes. They will can pull to left or right. Since drivers don't normally put that much pressure to the brakes. It can be a surprise when the steer tires have so much pull.

It just a guess because the front brakes are the hardest to lock up. They also get the least amount of use. So thay can pull left or right more when you really put a lot pressure to them. The computer on the truck might show how hard the brakes were applied.

I think someone already said this, bobtailing is the most dangerous way to drive and the hardest to stop. Because you have to many tires on the ground for the weight of the tractor.

 

Looking at the skid marks, they are all from the Truck. The 2 steers, go into the wall. The dual drives going sideways, get closer together, finally going together as 1, as The bobtail spun around. Looks pretty clear, they were all locked up, not just the steers. Actually You can see, the Drives locked up, long before He stood on it, and put it into the wall. At least He didn’t rear end anyone.

 

Looking back at that pic, I think you're right on the money there!

 

Even looks like the Drives bounced when He hit the wall, interrupting the skid marks.

 

Not in a million years. You lock up the steers and there's no more steering. You get air failure and locked up drives you can at least counter steer if your steers are free. It's always been that way.

 

My 1974 Pete 359 didn’t have any front brakes on it from the factory.
Just a spindle with a hub and a tire.
I really don’t recall any stoping issues with it bobtailing either?