I started this thread because the Ford vs Dodge started to wander a bit. The subject of keeping control on steep grades and the use of jakes is good. But the getting to the point of having to use an escape ramp is totally the last resort. A few months after the new highway was opened on the Lewiston Id grade a driver for Reyerson steel got into trouble and used the ramp 2/3 the way down. It had rained, snowed, rained, froze repeatedly. When the truck hit the ramp it didn't sink in the pea gravel. He shot off the end some 50ft plus in the air. The load load of steel was impaled standing straight up through what was left of the cab. Some say you can still hear him screaming on that part of the road. DOT failed to keep the the ramp tilled. The Lewiston grade is the only one I've seen with the last escape ramp being in town. The escape ramps dropping into Jackson Hole are on the opposite side of the road, you have to cross the uphill traffic to get to them. If I remember right that grade is 10% for four plus miles.
I think the air brakes you are talking about here are like a variable pitch prop because no kind of brakes are going to help if the wheels are not on the ground.I must be a sick sob but just reading what you wrote made me smile because it was funny just visualizing that truck 50' in the air but it was not very funny to the driver I am sure,just a combination of circumstances out of anyones immediate control.It is something to think about once in a while for any driver.Thanks for the wakeup call.Ron G
Around here there is one runaway ramp that I know of. It is downhill all the way and after the 3 gravel piles there is a short ungraded section and then a deep cut onto the transcontinental railroad. I remember an old timer said a truck actually wound up down there at least once. https://goo.gl/maps/1HFkDCeTRwL2
Not sure what the point of this thread is but I will share a quick story. I was loaded in a triaxle driving down a flat road getting ready to take an offramp and it was fairly downhill to a stop sign. Went to touch my brakes as I was getting on the off ramp when I realize my brake pedal was gone. The pin had slipped out of it and it had fallen off onto the floor. After a brief moment of panic I quickly steered back on the the freeway and just started down shifting until I was slow enough to hit them emergence break. A break pedal falling off isn't something you normally check but I always do when getting into a truck now.
Yeah, I remember hearing about that accident, must have been the last sick joke... the terror of losing the brakes, making it to the runaway ramp, feeling relief as he steered into the pea gravel... and that last horrifying realization about halfway up that the truck wasn't slowing. Air brakes are wonderful things but they have their limits too, and those maxi brakes that come on if you lose air are only roughly equivalent to about 60psi of application pressure IF the brakes are adjusted properly. The further the slacks travel the less spring pressure you have and the angle increases losing even more. I have seen more than one truck or trailer burn out the brakes on a long grade and "cam over" the S cams, which locks the brakes on for that wheel, kind of. Stuff happens. Another story... back in the early days of ABS systems, my dad worked for the local county. They were running Detroits at the time, 8V71's. A couple of the drivers weren't really used to the whole concept and would come down the long grade from the crusher/asphalt plant loaded in too high a gear, the jake wasn't holding back well and they would ride the brakes instead of applying them intermittently. If they used too much foot brake the trailer wheels would try to lock up and the ABS system would release air for that wheel, another wheel would try to lock, etc, and the driver, not slowing down, would apply even more foot brake. Ran out of air at the bottom of the hill, blew through the stop sign. Solution was to drop two gears, keep the revs up, jake worked better, air compressor kept up, use brakes to slow it well down and then release... Learning curve.
The point is with the problems that can occur with air brakes and the things that happen even with a supposed fail safe maxi can, people trying to haul loads that juice brakes were not designed to control. With juice or electric brakes you have no maxi and no real parking brake for loading equipment. we all know what happens when loading and you lose tongue weight. Slip sliding Away, I think that was in a song. Truck Shop
One problem with maxi cans is the fact very few mechanics and owner op's pull the T-bolt plug and check for broken springs on a regular basis. Most of the time it isn't til the trailer try's to roll away when sliding the axle's or backing under to hook up that anyone notices the spring brakes or slacks, manual or auto need some attention. Truck Shop
Pulling the caps and checking for broken springs was part of our annual DOT inspection check list. Lot's of trucks only have spring brakes on one axle. Same with the trailers. So, it's conceivable that an 18 wheel truck might only have 2 wheels that have "emergency" brakes.
The FMVS rules haven't been updated in years when it comes to parking brakes or how many axles require maxi brakes. For years heavy haul or lowboy's were not required to have them, maybe they still don't. I haven't seen any 48' and up flat, van or refer that does not have four spring brakes in years. Our three axle 53' have six, tractors have four. Any A trains at least that I have seen going back to 1990 have four on the lead and two on the pup. Before that time there were alot of single maxi setups on tandems. Even Sysco and Food service tractors have been four for two, sometime now. And long stroke cans are very common now. But I will add that those are common spec's for steep highways west of the Rockies. No one orders a truck without jakes in the NW. I don't know about the rest of the country. Truck Shop
I got juice brakes so hot they gave out 1 time when i was about 18. I was pulling a trailer that didnt have brakes and was going to turn at the bottom of a hill. The only thing that happen was i went straight and took the long way to were i was going. The worst thing about this is every once in a while i have a nightmare were im driveing a truck and hit the brakes and pickup speed then i come to a hill thinking i will slow down but i just keep rolling along untill i wake up.
It always made me stop and think when i was about to drive a old gas tractor that didnt have any maxi cans on it the only parkbrake was on the trans. I often wonder how many times some one drove off with no air and had to stop? Or had a air over HYD system and didnt have any air.
Seems like trailers are required to have spring brakes on all axles after 1964. I know I have seen them with no spring brakes. Those must have been ancient...
This dosent seam wright because i worked at a place that some of their trailers didnt have any and the DOT boys never said any thing.
Nope, after 19 74 , trailers were required to have spring brakes on at least one axle.
Hell I don't know.
Seen Cozad style lowboy trailers with only maxi's on the back axle.. worked great when you dropped the trailer on the ground and then tried to get it hooked up empty. Chase it until it hits something, lol.
Another difference most people don't consider: The rig in the other thread is an 8-10,000 trailer, 24,000 load, and a 6-8,000 p'up, so, 38-42,000 lbs gross. Hooked up and loaded, the four wheels, (not tires) of the p'up might be carrying 12,000 lbs, and the trailer is carrying 26-30,000. A tractor-trailer loaded to the fed formula weighs 80,000 lbs. 46,000 on the six wheels of the tractor, and 34,000 on the trailer. Ok, a couple of scenarios: Break one wire and lose trailer brakes, 42,000 lbs being stopped by 4 brakes designed for 12,000 lbs, over 300% overload. or Two or more things go wrong, and you lose trailer brakes, 80,000 being stopped by 6 brakes designed for 50,000 lbs, 60% overload A sudden change of direction is needed, 12,000 lbs trying to control 30,000 lbs or 46,000 trying to control 34,000
Getting under a trailer is no problem if you hook the hoses up first.Ron G
Ditto
True, IF your hoses will reach the back of the frame ramps, and if the dumb driver doesn't manage to cut one of those hoses on the frame somehow while trying to couple up, LOL.
I pull a Murray lowbed, and there are no spring brakes on it. Parking is by air pressure, and when that bleeds off, there are no brakes. To hook up, I have an extension so my air line will reach to charge up the air, then set the brakes so I can back under the ramps. Emergency braking would only work until the air supply ran out. As far as hills, my goal is all the way down without any brakes. I consider it a personal failure if I have to use the brake pedal for anything but an unexpected event, like a dumbazz pulling out in front of me. That way the brakes are nice and cool for the sake of said dumbazz so he can live to do it again. That said, if I do need the brakes, it is to slow to grab a lower gear in the event I did not start out low enough.