Disc Brakes and DOT Brake Check

Disc brakes started appearing on aircraft almost a soon as they were heavy enough to need them (1930's?)
They became the defacto standard on automobiles by the middle 70's, first just front wheels where 75% of the braking power is needed, then eventually all 4 wheels.
For YEARS the trucking industry has resisted because of the slight increase in initial equipment cost, which as has been stated here is more than totally recouped in less maintenance.
Let's forget for the moment how much better they perform in wet weather, below freezing temps (brake shoes stuck to drum) and far less fade down long grades. Particularly with trucks with automated transmissions which don't handle that scenario well with the less than stellar drivers in the pool these days.

In other words SAFETY.
At the moment less than 20% of all new trailers are so equipped, and probably less than 50% of tractors at all wheel ends.

Don't get me started....

 

Kentucky has a dyno they can use to test the Disc brakes. You have to know where the test mode button for your tractor is or the truck will flip out with you not moving but the wheels are and it will not pass from what l heard.

 

My truck has disc brakes and has 715k on the clock and the pads have been replaced once.

 

I've had level 1 with disc brakes. They just look at you and smile "oh you have disc brakes" and proceed to next part of inspection. Honestly on my kw pads lasted 900k.

 

I ordered a Great Dane dry van with discs about the time Covid hit. Still haven't heard back from that salesman. Of course I wouldn't buy it now because he probably wants double for it (quote was just over $40k then, very loaded dry van). On the 'don't get me started' theme, how does a dealer take info, put you in line on a 'list' he mentions in every conversation and then just simply drop you? I offered more than once to front some money. He wouldn't take it.

 

Just had new pads put on my flatbed this week. Close estimate to mileage is 500k and the shop said they still had lots of life left in them. If they don't get checked periodically and caliper or something screws up and the disc gets damaged, it can get expensive. I just figured while I was getting a couple wheel seals done may as well get them replaced.

Truck has them as well and in the 4 or 5 level one inspections it's been quick and painless. Gotten the sticker every time.

Personally would never own another truck or trailer without them.

 

Disc brakes have a measurement just like shoes. Seeing it is a different story.

I can see the rotors through tires. Outside. Inside not so much.

 

https://cvsa.org/wp-content/uploads/Inspection-Bulletin-2018-04-Air-Disc-Brake-Inspection.pdf