My brakes are smoking when on steep grades.

My company truck has all disc brakes. I would not go back to drums unless we had to. Disc are so much better. I think one big advantage over drums is no slack adjusters to worry about. Disc brakes can take more heat without overheating. Plus no brake fade. I have not seen or read anything about how much heat disc brakes take. As they get hotter they would expand against the pads. No slack adjusters to worry about if big in my opinion. They basically are always in adjustment unless something goes wrong.

 

I hope it was not a fuel tanker

No, the only emergency in your case is to ask your company to teach you how to operate an automatic transmission properly in mountains in order to maintain safe environment around and in front of a heavy equipment you took responsibility to operate.

PS: I really have a trollish feeling about the OPs post, but we post for public consensus, aren't we?)

 

Another solution to smoking brakes is the way I was trained to drive the mountains. Light Steady Pressure on the brakes. You can ride the brakes all day and they won't overheat or smoke. The trick they don't teach much anymore or people don't know . Drum brakes dissipate heat. The secret is not to apply more brakes pressure (heat) then the drums can dissipate. They already figured out the correct answer. It's 10 PSI or brakes pressure and you can ride the brakes all day and they won't overheat. You also need a truck with Applied Brake Pressure gauge. It's not standard gauge from factory.

 

And when they get hotter, they start to melt just like any drum breaks.. which is the same as grease, no matter how expanded they are against anything. Or am I wrong with the math?

 

10PSI at 10mph and 10PSI at 70mps is a bit of a dilemma with your theory.

 

@Grant3787
I drive the same truck you drive, difference being I haul gasoline instead of chemical.
I have 2 hills that are similar to the grapevine that I run in east Tennessee.
Here's how I run those hills loaded...
As I get closer to the downhill run, I slow to 30,and put the engine brake into 2.
As I start down the hill, I let it come up to 36,then brake back down to 30.
If it starts coming back up too quick, I do my Jake to 3,and repeat the process...
Biggest thing is preventing the brakes from getting too hot, and building up too much speed downhill.
Better to stay slow and in control than have it get away from you.
You'll quickly learn which gear you need to be in to maintain speed safely... I think I run in 7 or 6...I know it by feel and sound when I'm in the seat.
Better to go slower than trying to pull it back down in that truck.

 

I don't think it's possible for disc to melt. Drums get hot and expand. Drums will get so hot and expand the brake shoes can't reach the drums anymore. That were the brakes don't work anymore. Once the drums cool again they get smaller and the brakes shoes can reach them and the brakes work again.

When disc brakes get hotter they will expand against the brakes pad because the pads are on the outside pushing against the disc. Drums the shoes and inside the drums and can only push out so much. The drums can keep expanding beyond the reach brakes shoes.

 

In the last auto Cascadia I drove all you had to do to downshift was to push that shift lever toward the dash. There was no manual mode switch.

 

Wonder If Brakes Were Smoked:
CHP issues runaway ramp reminder following I-5 crash

 

I'm intrigued on the weight part. I've heard both claims. I dont know. The disc look heavy to me.

Good advise from everyone. But I will add this. Disc brakes can have fad. Its not as prominent as with drums. But they can in severe applications. The hot material gives off gases and can act as a pocket between rotor and pad. This is a big reason why you don't "fan" the brakes. Get on them, and stay on them. Let off stay off. Its ok to cycle them, just not to often.

This is why you see drilled rotors in performance applications. Give the gas a exit.

Disc brakes will glaze just like drums, if you have got them excessively hot, they need deglazed or replaced.