Disc brakes on a semi?

And yet after all this time there still seems to be misunderstandings (I’m being nice here )as to how brakes work.

 

I think the tractor abs cured the old problem of disc on the truck and drum on the trailer. I know several that are running them on the haul road and pulling drum trailers all the time, I have not heard of a problem.
The thing I have heard is they seem to not last as long in our environment and are expensive.
If there was any sort of problem with the truck trying to stop first, it would not work at all on the haul road.

A guy I knew died 3 or 4 years ago, and in his shop he had a 87 359 pete V8 cat 6 X4 with disc brakes.
It had the sum total of 46,000 miles since new, because he didn't like it with drum brake trailers.

 

I won’t go back to drums any more than I’d go back to a 10 manual. Both suck.

 

Never had a problem with drums, but never tried discs either. I likely wont either, as I have no intention of buying a new truck, and sure will not be retrofitting mine.

Like I said there are some complaints on the longevity on the new ones here, but we run in somewhat extreme circumstances, that highway trucks seldom or even more realistic, never see.

 

Are these air powered disk brakes? When the air gets cut off do the disk brakes lock up?

 

When air is evacuated, yes they lock up.

 

They need air to release parking brakes, and a seperate air supply to apply them.

Im not current on discs in trucks, ive seen a few more than 20 years ago. They beat drums in all areas of performance.

They probably will be superior to drum in mountain work or very responsive in ice or packed snow. Don't need anywhere near as much. For me something that big will need to be vented and slotted. I would not want solid metal discs. It's not necessary and maybe a problem in mountain work.

Ive had both. But disc brakes will take much more before they finally break apart, and when they do.. it's going to be expensive because the pads were not replaced in time. Pads are cheap, discs are not. If you do your daily pretrip you will recognize when the discs have had quite enough. The surface of the disks facing the pads will show vertical marks of the venting between them before they fall out in pieces.

 

The difference between discs and drums?

Disc is ALWAYS ready. ALWAYS predictable. Your big toe will suffice for slowing most of the time

Drums are (say prayer) before applying full force via size 13 steel toe.

Disc on trailer = Heaven.

No more adjustments.