It applied before the CAT swap as well. pump to stop not slam em on. Let the shoes get a better grip with each release and application.
No argument. Your braking description used to be the standard, taught to everyone for every vehicle. Now they just teach "stomp it and let ABS modulate".
In the early days of ABS a skilled driver could get a shorter stopping distance than ABS. That hasn't been the case in quite some time.
Still, in most vehicles I could care less whether it has ABS or not. My 939series are the only trucks I actually want it in.
Let's digress and talk a moment about limits. Limits in anything. The only way to precisely define a limit is when you exceed it. Bursting strength on a line for instance. You put 1000psi on it. It didn't burst. You still have no idea whether the actual limit is 1001 or 10,000. You start adding pressure in 1psi increments. You still have no idea what the actual limit is, only that is is higher than what you have already applied. The line bursts at 1081psi. Now you can stick a hard number on the limit strength of the line at 1080psi. But until you exceeded it you had no idea.
Apply this to braking a 939series truck. You hit the brakes hard. They didn't' lock up. Obviously you weren't at the limit and could have hit them harder. How much harder? No way to know for sure until you lock them up.... with ABS in place you know you hit the limit when the ABS actuates. Without it you know you hit the limit when they lock up and kill the engine.
Experience gives us a good idea where we'll find the limit. This experience is informed by previous instances of exceeding the limit and extrapolation from similar experiences. But exceeding the limit of braking on a 939series truck without ABS has potentially dire consequences.
These big airbrake trucks handle differently than a pickup truck. Many people getting into the MV hobby don't' have experience driving anything more than a pickup truck. Lockup an m818 without ABS and you can recover. Lock up a 939series truck without ABS not so much.... an m818 had a manual transmission....
Further, a 939series truck brakes a lot different than a large civvy dump truck. My experience has been that a 939series truck will potentially lock up the rears much more easily than an empty civvy dump truck of roughly the same class. In the two instances where the ABS activated, I didn't think I was all that close to the limit.
So, applying experience from a pickup truck will bite you. Applying experience from a heavy-ish civvy truck will also bite you. And no vehicle other than a 939series truck without ABS has quite the same penalty for exceeding the braking limit.
This comes up every time the ABS is mentioned. "I'm a good driver. I learned without ABS. I don't need ABS. Only the incompetent inexperienced need ABS." With the dumbing down of everything in our world today, it's easy to dismiss the ABS as just another unnecessary safety feature. But the M939series truck is a different animal. The ABS on these trucks isn't about fixing driver skill - it's compensation for the deficient transmission/torque converter. Fix that torque converter and then you can relegate ABS to the category of unneeded safety device.
All of this is completely irrelevant to this thread though. The truck the guy is looking at has ABS.
