My brother asked me the other day why big trucks all have drum brakes. I could not answer him. I figured since old A bodies do have drum brakes, someone here might know why they are preferred on trucks. Anybody know.

Sam

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Drums are cheaper.

There are disc brakes for OTR trucks. With the new braking requirements, you will start seeing more of them on the road.

CJ

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Part of Tyrde-Browne Racing

Disc brakes have been on big trucks in Europe (and the rest of the industrialized world where the international, formerly "European", UN vehicle regs are recognized) for many years. The primary barrier to their adoption in North America has been US regulators moving with their usual molasses-in-January "speed" and odd priorities.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I know I've had some as late as 72 where "flaky" is a good word for how they worked. Some brands of trucks you can buy the parts to convert them because some came with disc. Dodge doesn't have that eurika moment. They werent made with disc or AC or power steering. You have to make it all yourself.

There is a guy claiming he will sue you if you make your own but I wouldn't pay much attention to him. I intend to make the disc brake plates that bolt to the spindle and sell them for a decent price. Might be a long time before I get there but it doesn't take a brain trust to make them yourself. Got torch?

Danny

I've seen medium duty 2 axle "box" trucks that have 4-wheel disc brakes. These are essentially just large versions of passenger car stuff- boosted hydraulic calipers. The BIG rigs have air brakes- do they make an air-controlled caliper/disc brake system? I'd be interested in how they accomplish that.

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63 Valiant Wagon
225 - 4 bbl

Air operated disc brakes are starting to come to the market.
What little I've heard from the people that have used them, it looks like it will be the wave of the future.

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66 Valiant, 225.
84 Van, 225.
71 Maxi-Van, 318
60 Valiant wagon, 225
87 Maxi-Van, 318 4spd

Having been a truck mechanic back in the '80's when disc brakes first started making the rounds, I can honestly tell you that they sucked. Rotors warped like plastic, pistons stuck, and drivers hated them because they were hard to get to work without locking up. Trailers with disc brakes on them could be bought incredibly cheap because nobody wanted the frikkin' brakes.

Hopefully they have been improved.

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Official Cookie and Mater Tormentor.

Correct me if I'm wrong, but I believe one of the main reasons for keeping drum brakes on big trucks is reduced maintenance due to the much greater mass of lining material.

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Joshua

I'm guessing that now that the parking braking situation is solved, and of course, air brakes now have a decent anti-skid system. The disc brake sets are now ready for prime time.
Having had a set of drums overheat on a 8% hill, and lose most of their effectivness. A set of discs that hold better when their hot would be nice.

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66 Valiant, 225.
84 Van, 225.
71 Maxi-Van, 318
60 Valiant wagon, 225
87 Maxi-Van, 318 4spd

I drove a '80 model Ford LT9000 with front discs. IIRC they had a master cylinder and the rears were air over drum.

Air brakes have lag time. Putting them on cars could cause problems.

As a driver I am required to check the brakes for wear on my pre-and post trip inspections. I can't see through the dust shields.

I can tell you one thing, they stop really good with the discs! If the ABS is malfunctioning and the trailer may or may not have ABS? Things could get weird.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick