Educate me on the dump...the M929 / M930

[LCA078]

The dump bed on the M929/930 is shaped differently than civilian dump trucks and has an odd gate arrangement. I'm interested in getting one to move build roads on my place, haul brush/trees to the burn pit, etc. but not sure how well it's suited for those tasks. The civilian dump trucks are good at spreading road base by chaining the tailgate but no idea if the same can be done with the military dump.

And yes, I know the 930 is the rare w/winch version but listed it for someone searching the forum in the future. I'm asking about the bed/tailgate set ups.

 

[162tcat]

You can meter the gate with chains to spread gravel but keep in mind you’re only going to get about five or 6 yards in it versus 10 or 12 in a civilian dump truck. If your property is really muddy or swampy, it would probably be good for that. If your property is fairly dry and you just want a dump truck to move material, get a civilian dump truck. I have an M817 w/w which is pretty much an older version of the m930. The bed is the same.


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[simp5782]

817s are fairly cheap. 929s and 930s sell in the 20,000 range now. Along the lines of a m917 in private hands. The 917 can haul 19 yards and twice the power. just food for thought on the 929s

Almost cheaper to buy a M931 tractor and have a dump kit put on it over buying a 929 and a bigger bed

 

[fasttruck]

Read the reading: then operators manual, in the case of a M817 is TM 9-2320-260-10 explains how the tail gate works. and yes it can be used to spread gravel by manipulating the chains on the gate when the gate is in the top hinged moie.

 

[NDT]

The mil dumps are well suited to hauling stumps and brush with the tailgate configured in the rocker mode.

 

[BKubu]

You can meter the gate with chains to spread gravel but keep in mind you’re only going to get about five or 6 yards in it versus 10 or 12 in a civilian dump truck. If your property is really muddy or swampy, it would probably be good for that. If your property is fairly dry and you just want a dump truck to move material, get a civilian dump truck. I have an M817 w/w which is pretty much an older version of the m930. The bed is the same.


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The bed is the same, but the cab protector is taller on the M929/M930 to clear the exhaust and air intake behind the cab. I've seen pics of an M929?M930 beds on M817s and you can see the difference.

 

[LCA078]

Read the reading: then operators manual, in the case of a M817 is TM 9-2320-260-10 explains how the tail gate works. and yes it can be used to spread gravel by manipulating the chains on the gate when the gate is in the top hinged moie.

Ahhh, it's easier to see in the 800 series manual. The 939 series doesn't make sense to me as it refers to using the wings so I don't understand how it meters the dump. I uploaded the spreading section from each manual here.

 

[fasttruck]

Using M 817 dump body is "quarry mode" where load goes over top of gate. Care must be taken when changing from top to bottom hinge that you do not get both sides released at the same time as this will allow that very heavy gate to fall off which is usually a bad thing.

 

[LCA078]

I’m assuming quarry mode is named because of the raw unscreened rock and dirt fresh from the ground? And the purpose of quarry mode means a mixture of large and small things or sticky things like snow can flow over the over instead of jamming up trying to go below the top hinge?

 

[LCA078]

You can meter the gate with chains to spread gravel but keep in mind you’re only going to get about five or 6 yards in it versus 10 or 12 in a civilian dump truck.

Is the yardage limited by the dimensions of the bed or by the hoist? The truck itself should hold a lot more weight wise than just 5-6 yards when not on rough terrain.

 

[fasttruck]

Table 2-3 on pages 2-130 & 131 lists the weights of various materials expected to be hauled in 5 yard dump trucks. Most of these commodities will cube out before they weight out. A "snow cone" load of wet clay will overload the chassis. Table 2-3 is in the previously referenced TM 9-2320-260-10. People who haul "fluff" loads build sideboards to increase the cubic capacity.

 

[LCA078]

I saw the tables that show the weight per yard of various materials but it doesn't help me understand the true limitations of the M929. I agree with Wes's point of adding a commercial dump bed to a M939 series is a great solution. I have a M925 project truck that would make a great project for this since it's already has hydraulics- this is why I need to make a decision of either going the route of turning my 925 into a dump or picking up a 929/930/817/etc. My need for a dump is to improve my ranch so I'll be using the dump mainly 'offroad' but not in the true harsh conditions these trucks were designed to handle. I've priced out used commercial dumps here in Texas but I haven't found a good deal compared to building up my 925 or getting a mil dump ready to roll.

So after the feedback here and thinking through my options, my question is then what's the weight capacity of a M939 chassis? I know it's a '5-ton' but there is a lot of discussion these trucks can handle 20k of load when driven correctly. I think 20k may be excessive but if I put a commercial dump body on my 925, I need to know exactly my limiting factor so I don't hurt myself or someone else.

Edit: I'm still curious if the M929 dump is 'limited' to 5-tons because of the hoist configuration. It doesn't appear to be a scissor lift nor a multi-stage lift so maybe it's limited in the initial lift due to the geometry of it's set up. A commercial multi-stage setup pushing straight up is the most efficient use of force and minimizes strain on the frame. Anything that pushes bed upwards with a sideways component can easily overload a chassis even though the load is well within limits.

 

[simp5782]

I saw the tables that show the weight per yard of various materials but it doesn't help me understand the true limitations of the M929. I agree with Wes's point of adding a commercial dump bed to a M939 series is a great solution. I have a M925 project truck that would make a great project for this since it's already has hydraulics- this is why I need to make a decision of either going the route of turning my 925 into a dump or picking up a 929/930/817/etc. My need for a dump is to improve my ranch so I'll be using the dump mainly 'offroad' but not in the true harsh conditions these trucks were designed to handle. I've priced out used commercial dumps here in Texas but I haven't found a good deal compared to building up my 925 or getting a mil dump ready to roll.

So after the feedback here and thinking through my options, my question is then what's the weight capacity of a M939 chassis? I know it's a '5-ton' but there is a lot of discussion these trucks can handle 20k of load when driven correctly. I think 20k may be excessive but if I put a commercial dump body on my 925, I need to know exactly my limiting factor so I don't hurt myself or someone else.

 

[LCA078]

Thanks, Wes, for pointing it out it the TM. It was so obvious, I forgot it was there and just remembered folks discussing it. Looks like adding a commercial bed to a M939 series can add significant capacity over a M929/M930 and in a safe manner which matters a lot to me.

 

[fasttruck]

The issue everyone forgets to analyze is not how big a body I can put on this or does the hoist have the power to lift it, but how much can you STOP with Army brakes which did not envision these loads. A 5 ton dump truck is designed to support a construction engineer platoon when they go out to put a culvert in someplace. For volume and heavy hauling the Army bought International Paystars and later M 917 tri-axles to do this stuff. If you need to put 100K in the box get a DM Mack with a triple frame, 68000 rear and 24" rubber and knock yourself out. This site is besieged by ill informed people who want to make an Army truck into an aircraft carrier or tow a M105A2 trailer 300 miles home with their F150 pickup. Military trucks can tolerate being overloaded but the question is for how long. Can points everywhere are full of the ghosts of trucks whose operators tried and failed to overcome gravity which is instantaneous, irreversible and irrevocable.

 

[LCA078]

I hear ya, Fasttruck, and agree with your concerns as there are idiots out there that don't comprehend limitations of their equipment. Worse yet, are the clueless ones in the average size car or small SUV who will speed up and zip in front of a fully loaded truck plodding safely along in the right land and then almost slam on their brakes trying to make a right hand turn. Since I live in a rapidly developing semi-rural area with lots of strip malls and soccer moms, I've seen loaded trucks (dumps, roll-backs, heavy equipment haulers, etc.) lock up their brakes because the clueless idiot jumped in front instead of being safe and getting behind the truck to turn. Add in a over-loaded truck like you're referring to and it's a disaster waiting to happen. My truck will be used on my ranch and safely away from the knuckleheads. So acknowledge your statements but not sure how they play into my original questions about learning the limitations of my equipment.

 

[Glenngineer]

817s are fairly cheap. 929s and 930s sell in the 20,000 range now. Along the lines of a m917 in private hands. The 917 can haul 19 yards and twice the power. just food for thought on the 929s

Almost cheaper to buy a M931 tractor and have a dump kit put on it over buying a 929 and a bigger bed

This is a M931A1 with an aftermarket box ,if you want all the good stuff it's not inexpensive .

 

[LCA078]

Nice truck. Is that an electrically driven pump or did you tap off the transmission PTO or engine fan belts? PSI of system? What size reservoir needed for that multistage cylinder? I know, lots of questions, but that is pretty much the exact setup I'd want.

 

[fasttruck]

Reference is made to post 16: There is not much to understand. The design load limits are stated on the vehicle data plates and in the -10 manual. Exceed them at your own peril. The only way to really know what it will do is test it to destruction and then you will understand the parameters. Using the vehicle in an off the public road setting will limit your liability but it will not extend the service life of your equipment.

 

[Glenngineer]

Nice truck. Is that an electrically driven pump or did you tap off the transmission PTO or engine fan belts? PSI of system? What size reservoir needed for that multistage cylinder? I know, lots of questions, but that is pretty much the exact setup I'd want.

Air shift PTO with direct mount pump,not sure of the PSI or tank volume. I hired the job out because I work full time and I wanted it done for the spring.they did a great job it has all the good stuff .