Dump Truck Build

[ahub86]

(01-19-2021 )redbeard Wrote:  Getting ready to retire and one of my units is a super clean T800 with long wheelbase and originally a truck.
Thinking of adding a dump bed to it and keeping it for chore duty as clean dump trucks are nearly impossible to find at a reasonable price.
What does a new dump bed and pto run to install if I may ask?

This one is 19’6” long 1/4” floor 3/16 sides and front all AR 450 steel and I have the optional high lift tailgate. For the dump bed setup with hoist, pto,pump, tarp system ,and in cab controls my bill at the dump body dealer was about $25,500 after FET and sales tax. Probably could shave some money off that depending. If you wanted a thinner gauge steel or no lift gate (that I s a $1500 option). I mounted it myself so there are other costs to think of there, but the dealer who sold me
The body had quoted me about $10,000 to mount it and paint it with single stage paint. Or on the flip side if you want to spend more I also quoted an aluminum body with a steel floor. That was $38,000 plus install.

[redbeard]

You did a nice job ahub86, good to see such quality work coming out of an owners shop.
Please do not under estimate the value of up-grading your fuel pump plungers and tappets to newest and best. I wouldn’t even start it up again till I did a look see.
Are you part of the Cummins DOC campaign? And is your oil pressure bypass valve the updated one? A little white paint on the big plug up by oil filter housing is Cummins way of marking that the bypass was done at Cummins after sale, it has no effect on oil pressure at running temperatures, for bypassing if filter plugs or start up and cold thick oil
R

[ahub86]

Thank you red beard. The truck showed an open campaign on quickserve for the scr when I purchased it. My brother in law is service manager for a Cummins certified shop in my area. He took care of that for me in their shop.

So the oil pressure bypass is a question I still have. The plug IS painted. About half the plug is painted black. I assume this means someone had upgraded. Would I be able to see the difference in upgraded parts if I opened it up and looked?

I should have all the odds and ends of mounting the body wrapped up this week, the. The head is coming off that fuel pump. I have the parts sitting here ready to replace what’s inside. I can’t imagine getting all this work finished up and the truck painted and polished, and then have my pump plungers explode and take out my engine before I even haul a load. It would be hard to bring up the subject to my wife! Lol. I am on it.

[hhow55]

  Est_15058_from_HERRERA_FABRICATING_INC_14136.pdf (Size: 355.47 KB / Downloads: 174)

[ahub86]

Build and install and paint for $12,000? Wow that’s a deal. I thought my dealer was a little high at the $10k mark to install and paint this one. But if someone came to me now and asked me to install and paint a body for them I would tell them $10k. Lol.

[Kingman11]

Always liked looking at build threads. It turned out nice! Good work!

[Rawze]

One concern I see with that build is those rear axles.

I did not see anything indicating that the rear axles were upgraded to handle all the weight on the back end with the dump bed up and all the weight sitting back there. - Most dump-trucks with larger dump beds like that I have seen, have really stiff and extra big thick leaf suspension springs, cross-members, larger than normal torsion bars, extra heavy duty axles and housings to handle this so that the back-end does not get distorted over time and so that the back-end is not soft under the immense weight shifting onto the very back axle alone once it is all the way up.

The pivot point looks like it is a fair bit behind the back axle too... Seems it would make it more unstable than normal and possibly a bit dangerous under really heave loads?.

Not trying to burst anyone's bubble there, it is just what comes to mind when looking at the pics, etc. - I am just speculating, I have never owned a dump-truck, but these things would be my concern.

[ahub86]

(01-20-2021 )Rawze Wrote:  One concern I see with that build is those rear axles.

I did not see anything indicating that the rear axles were upgraded to handle all the weight on the back end with the dump bed up and all the weight sitting back there. - Most dump-trucks with larger dump beds like that I have seen, have really stiff and extra big thick leaf suspension springs, cross-members, larger than normal torsion bars, extra heavy duty axles and housings to handle this so that the back-end does not get distorted over time and so that the back-end is not soft under the immense weight shifting onto the very back axle alone once it is all the way up.

The pivot point looks like it is a fair bit behind the back axle too... Seems it would make it more unstable than normal and possibly a bit dangerous under really heave loads?.

Not trying to burst anyone's bubble there, it is just what comes to mind when looking at the pics, etc. - I am just speculating, I have never owned a dump-truck, but these things would be my concern.

Yes Rawze you are right these are all good things to look at. The truck has 46,000lb rears. Most proper setups for the weight we handle here in New York have a 20k steer axle, a 20k pusher and 46k rears. 86k worth of gvw and in the case of this wheelbase 73,750 lb gross max allowed. So typically with the bed down on the frame when loaded the weight is distributed properly that no axle is even close to over rating.

Tilting the bed up is a different story. The center of my pivot in my rear hinge is 5” behind the rear of the tire. That puts it about 6-7 inches from the last set of airbags where the rear axle bolts up to the frame. The hinge is built on 4x4x1/2 angle iron cut into and welded across the span of the frame rails. About 1-1/2” from that hinge I placed a crossmember. That spans across the area that the airbag hooks to at the bottom of the frame. This stiffens the rear section of frame up real well. One of the main things to worry about with a dump is when lifting the body on uneven ground, which is like 95%of the time (barely ever on perfectly level surface). So the twist action of the dump leaning from side to side is what we are trying to brace for in the back. The front axle takes most of the abuse when dumping as far as down pressure from weight. That hoist in the front starts pushing down on the frame behind the cab and takes a lot of the weight that was evenly distributed across the frame and localizes it right there behind the cab. You can actually see the front end go down or If you stop and start the body while it’s raising it will bounce those front springs hard. Granted the rear pin shares this load with the hoist, but the bulk of the weight is being lifted in the front. And the load when it comes out will start falling from the back of the pile first. So by the time the rear of the body and the hinge have gravel crossing it is flowing through, where the front still has a pile up in it. And there is especially a lot of side pressure on the pins and welds holding everything together. Where you have 22ton of material in a 6,000lb box lifted off the frame rails and you lean side to side or tailgate spread over uneven ground it’s tough on things. Takes experience to know what you should and shouldn’t do with it.

This truck is defiantly a heavier set up than a tractor. I have seen quite a few set ups like this with air trac suspension that have lasted quite some time with no problem. My buddy has one with 700k on the odometer. Which is high for a dump truck. But they do take more abuse as a dump for sure. If I was mounting a box on his 700k mile truck right now I know I would have to account for the frame having a slight upward hump. They develop a slight hump over the rear suspension which is usually more pronounced in a truck like a Mack with camelback suspension. In that case the rear suspension comes to a center point and then goes up to the frame where the trunnion stand bolds and kind of centralizes where the weight of the 2 rear axles is put on the frame. I mounted a body on my last truck(a Mack) and had to keep the body hinge up in the rear slightly to account for the hump so that when the bed was loaded and the frame flexed back down, the bed sat true on the frame rail from front to back. Otherwise you get a situation where the bed is loaded and whenThe bed frame comes down to contact the truck frame, it puts an upward pull on the rear hinge.

These things in consideration is why I chose to do the project myself. There is a certain way I wanted things done and some serious things to consider. Having air suspension on a dump isn’t for everybody. But instead of spring or beam it was what I was looking for in this project. First two trucks had solid suspension in the rear. No springs no rubber blocks. Solid beam between axles that pivoted on a trunnion between them. Very stable. Personally my business has changed over the years from mostly private off road work and site construction to road construction. That changed what my suspension needs to be Most guys working road construction with air suspension have no problem with stability. Unlike being off road out on uneven ground. And now I travel all NY and PA working on projects for one company. Surprising amount of my time is spent on road empty. I think my back will thank me for the air ride.

I am glad you were thinking about it this way. I didn’t really mention in my post how many Xm factors are included in setting up a dump truck properly. You won’t just buy any old truck and slap a body on and go to work. Even in my own business there are factors to think of that this truck isn’t set up right for. But I just have to set it up best I can for most of what I do. For example, there were multiple days last summer I went over 600 miles in a 12hour day. There were multiple days I went less than 20 miles in a 12 hour day. Also the truck has to be able to get out on the highway and cross the state at a reasonable speed to keep up with traffic, but I have to be able to gear slow enough to get under the boom of a milling machine and creep forward while being loaded. I have to have enough over hang at the back of the box to dump in a paver. Too much overhang and the rear of the box is too low to the ground when tipped up and won’t work in a paver. Lots of variables.

Sorry to write a book here. I just happened to have some down time right at the moment and I love talking about dump trucks. Lol

[Pigpen 2869]

You did a nice job. Did you remember to whack the back of the cab with a grinder and tell your customer “Fuckked if I know how it happened” ?????