Why are air brakes still required on heavy trucks and buses when hydraulic or electric are more reliable.?

Fade......big old trucks use alot of brake shoe material you have to adjust them weekly,daily if you are in hilly terrain. Now I may be old school but I understand that huge amount of brake material on the shoe and "S" cam that engages them is the best most economical way to stop a semi or class 8 dump There maybe a better way or the technology may exist but changing the whole transport system to adapt would cost a lot and be hard to inter gate remember you hook to other equipment all the time trailers jeeptrucks dollies for trains all hook up and work together so it would be a matter of changing all the other stuff also.

Over 20 years of haulin' with air brakes i rarely had a problem and never a major failure they are also easy to repair even on the road if need be. My best stopping tool was me making damn sure my road speed was correct for my load and road and traffic conditions.

So any major change would take years and cost a bundle and air binders always worked well for me a care full operator the engine brake is also a major advantage when slowing them down.

How less reliable? Let air out truck stops Put air back in truck brakes turn off. Besides the size of the drums and shoes are huge! Weight alone pushes tires into the ground and trucks stop a lot faster than you think. Given number of miles cars wreck a whole lot more than professional CDL drivers. Remember this when a CDL driver gets a ticket they cannot attend comedy defensive driving to get the ticket removed! Next time you see 72,000lbs stop in time. Thank the Westinghouse Airbrake Company from the 1930's And newer self energizing air brakes on trucks today

Actually, Air brakes are more reliable. And can handle the heavy loads trucks have to carry. Let alone the environment extremes that they encounter, all over the continent. Also, there is a secondary system for the airbrakes, when there is no other means with hydraulics.

Most of the answer above are right on but they over look one point, The big truck need to be able to drop and hook to another trailer.

This is the advantage of air brakes verse hydraulic lines and i would like to see a mechanical break system to a trailer.

Air is alot more fail safe becouse of the size of the vehicle and the length of lines to run air is only used to hold breakes off massive springs push the brakes on also heavy vehicle breaking isnt behind everything else u can get ABS in trucks and everything

the answer before was correct except one thing big trucks also need more room to stop. if they are cut off by someone in a hurry they can find themselves run over.hydraulics would take approx. 5 to 6 secs to activate after the driver hits the brakes where as air only requires 2 to 3 secs. to activate. that is for trailer brakes not the truck itself is faster but harder to stop with 45,000 lbs pushing it.

because air reacts faster than liquid does,,and this make for a faster response for the brake system on a big truck,,good luck,,hope this helped.

Air breaks have the added advantage that if they loose pressure the breaks will lock.

dodge man said it best...