Worst Part of pulling End-Dumps

The technique I use, of course making sure the trailer is as level as you can get it, not leaning left or right. My rig has the trailer suspension dump valve and the gate release valve mounted on the left-rear of the trailer.

1. Set brakes, trailer or tractor (parking).
2. Get out, walk to rear of trailer, undo the manual load locks, unroll tarp, if it's setting level, dump suspension, and release gate.
3. Get back in tractor, dump tractor suspension. Also my trailer is a spread-lift axle, so I make sure my lift axle is raised.
4. Now if I had set the tractor (parking) brakes, I will release them, and either set the trailer (red emergency) brake, or use the Trailer hand brake.
5. Engage PTO, start raising bed. Watch the bed and trailer tires in your mirrors. If you think you see your bed leaning, STOP!!! Set your parking brake, get out and look to see if it is. Sometimes the vision we get in the mirrors are not what's actually happening. Better to confirm it while you have a chance to stop it from going over. When bed is at the top of the 3rd stage, material generally is about 1/2 up on the tires. I'll release the hand brake, and apply light pressure to the foot/service brake. Applying too much pressure will also affect the trailer brakes. This will then allow the trailer to walk forward while the bed finishes raising.
6. Reduce pressure on the foot/service brake allowing trailer to roll forward from being pushed by material. This is controlled by keeping light pressure on the foot/service brake. This is done so that the material pile is neat and not strung way out.
7. Once I see that the material is done falling from the bed, I set the trailer brakes using the hand brake, and start lowering the bed.
8. Push the tractor suspension switch to fill it, then once the bed has lowered about 1/2 way, I slowly pull up enough so I can roll my tarp and clean up the rear of my trailer.

Our trailers are equipped with pneumatic vibrators. I will engage the vibrator once the bed is raised all the way up, unless there's some circumstances where I do not want to raise the bed fully (un-level ground, or very strong cross winds).

This is a general technique, and is not used in all situations. If the ground happens to be a little soft, or not quite level, I will not walk the trailer forward, I will always set the trailer brakes and walk the tractor back. Then once dumped, I will gently drive forward until I can start lowering the bed. If I have a nose-heavy load of material that is sticking, I'll make every effort to ensure the trailer and tractor, including the area behind the tractor, since this is the path the tractor will be moving on, is level. If not, I will string the material (AB-3 in the winter time) out.

Another quick note; When dumping in strong winds, always try to point your nose into the wind or away. If you can't, then do the best you can. A loaded trailer is more likely to layover than an empty one. The key is to get as much of the material that is in the front/nose, to the rear before raising it all the way.

 

The only time I've hauled any scrap material, was when I worked for a construction company. We helped with the clean up after a tornado hit a small town. The trailer was a 28' barrel (half round). We removed the end-gate after a short time, because the stuff would get lodged, half over the gate, and under. It will also damage the inside of the bed, pitting, denting, scarring it. Then when you want to haul loose bulk, it will not want to slide out. Other than that I think there's really no difference. Oh and pay attention to your loader-man. If it's some idiot, they may damage your rig just trying to load it, or be swinging over the cab, which is a big, big, no-no. Don't ever let a loader swing material above your cab!!

 

Well this past week I've had to violate both, no way around it. I did not want the tractor walking back, and really didn't want the trailer rolling forward, but the situation dictated otherwise. The situation;



That's looking at the area where I dumped CKD (Kiln Dust), downtown Amarillo. It was raining, and muddy. They had to blade a small area so we could dump. We backed into the far side, leaving our drive-axles on the concrete entrance. My drives were on the edge of this entrance. If I walked the tractor back, they would have dropped off of it, which was at least a 6-8" drop. I was angled into the entrance, no other way, due to the small street and cars parked along it. So if my drives dropped they would have dropped off at different times, big-time sway for the bed. So I set the parking brake, and allowed the trailer to walk forward.

When we step on the service brake, we feather it, so it does allow the trailer to move and also the tractor some. ALL of our experienced drivers (20+ yrs with rock buckets) do this. They also will only use the trolly. A situation where we do this a lot is when we dump Buildex® (CNL). That stuff comes out very fast, and we always dump it at DOT mixing strips, that are hard-surface (blacktop). Before your bed is at the top of the 2nd stage you have it piling up around your trailer tires, I mean all around them, so you need to be able to scoot forward, both tractor and trailer to keep from burying your tires in it.

Unless you have the service brake applied so hard that it is not allowing either to move, it will not damage the PTO. I'd be more concerned about the valves being damaged.

Now I found out that if you lose most of your secondary air pressure with the bed up, you're stuck!! It will not come down. This happened to me and the other driver that dumped in the above muddy lot. We lost the air having to jockey around to get in there. Before the bed will come down, you must get the air back up to around 85-100 psi. We also have air-vibrators on the trailers, which suck the air out big-time. We have to use the vibrators with kiln dust, that stuff will stick, especially when it's humid or wet. So we sit with our beds up, RPMs raised, running the vibrator for a few minutes. It's not an issue if you don't have to jockey around so much before you dump, you can keep the air pressure up above 110 psi.

To compound the bed being stuck in the air, I had power lines about 10' in front of my bed, the concrete entrance had mud on it, was wet (it was raining at the time), and my left-front drive tires were off the ground. I couldn't get any traction to move. I finally got the workers to blade the material from behind the trailer so I could go backwards. I finally managed to get the bed to come down enough so I could pull it over the entrance drop-off, then out into the street. What both of us discovered, is that there is something weird with our trailer air supply setup. Once the pressure had dropped too low, and we had brought it back up, we had to go back to the trailer suspension dump valve, dump it (pull it out), then push it right back in, to get the bed to lower. We both have no idea why, but it worked.

Just a final note, if anyone hauls kiln dust or fly-ash and has to dump in the rain, you'll have fun trying to brush off the dust on the rear of your trailer. Once it gets wet, it is not dust. It's more of a paste, that stuff just smears around. My trailer was a mess after that. Then I had to go "mud-buggy" following that. Drive across a pasture to load rock. I got plenty of practice controlling a jack-knife. This was a 1-1/2-2 mile road, slimy red clay stuff. Was suppose to be gravel, suppose to be. It was curvy with hills.