Dump Truck Build: 2000 Mack DM690S

Hey man I’m really impressed. Not only are your skills seriously solid and your work confident, you’re a good writer too. Not that we’ve met or anything but you’ve got a plan, did the homework, have a plan b, probably multiple, so you’ve thought through the risks and have it mapped out. Serious kudos, from a guy in a completely different line of work. that kind of thinking anywhere is valuable, on top of the skills to make it happen.
 
Interesting looking wheels on the Mack.
They are called Dayton wheels. There is no center on the actual wheel, it's basically just a steel ring. They use wedge clamps that fit over the studs and are held on with nuts to basically wedge the steel wheel/ring to the cast hub and spokes. They are incredibly strong and are easier to change in the field because the wedges and nuts require far less torque than a Budd or Hub Pilot rim to stay tight. The down side is you have to center them on the hub when you install them. I lay a wood block next to the tire and spin the entire wheel end and you'll see the tire wobble in and out and you alternate tightening the nuts little by little until they run true.
 
Hey man I’m really impressed. Not only are your skills seriously solid and your work confident, you’re a good writer too. Not that we’ve met or anything but you’ve got a plan, did the homework, have a plan b, probably multiple, so you’ve thought through the risks and have it mapped out. Serious kudos, from a guy in a completely different line of work. that kind of thinking anywhere is valuable, on top of the skills to make it happen.
Thank you! I am trying to make a name for myself in this industry and feel like I am doing very well for 25 years old. Professionalism is the key to a young guy being taken seriously especially when you show up with a truck older than you to a technical recovery or complex crane job. You must never show wavering confidence in your plan to a customer even if you are having to change plans on the fly. I loosely follow the Big Stick ideology in that you are always humble in your skills but ready to throw any amount of equipment necessary to complete a job. I have a serious issue with saying no to a job or the word can't.
 
I have fallen behind both with progression this truck and with posting updates but here is a short one. I ended up having to replace the clutch and have completed that along with new U joints and carrier bearing in the drive shaft. I also replaced the output shaft seal in the transmission and a few other minor transmission parts. What you see here is prep work for the trunnion stand replacement. I decided to totally remove the rear drive axle because it is caked in concrete that I would like to clean off and it gives more room to tear down the suspension. For those wondering those U bolts are 1.250” in diameter and torque to 1650-1800 foot pounds. The springs have to be lifted by engine hoist or forklift. I bought a torque multiplier to use with the 3/4” torque wrench so I could do all of this in house. I installed the PTO unit on the transmission while it was out so it is now ready for the hydraulic pump when the time comes. The new 16.5’ bed should be ready for shipping on June 4th.
 

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Spring packs came off tonight! Spent most of the day at Mo-Kan watching the drag races but found time before dark to get these off.
 

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Trunnion stand is officially out! Time to paint the inside of the frame where it was and start putting the new one in.
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Great work and I admire your skills and ability to tackle such a heavy duty job all at one time. What exactly are you going to haul with it? I imagine almost anything that will fit on it?
 
Great work and I admire your skills and ability to tackle such a heavy duty job all at one time. What exactly are you going to haul with it? I imagine almost anything that will fit on it?
Thank you. I have a job offer to haul material for the local concrete plant so I hope it will stay busy with them and will fill in with work for local farmers as needed hauling gravel, sand, road stone, etc. I can slip a liner in and haul asphalt if I need to as well. I ordered the new bed with an asphalt apron as a backup plan.
 
Thank you. I have a job offer to haul material for the local concrete plant so I hope it will stay busy with them and will fill in with work for local farmers as needed hauling gravel, sand, road stone, etc. I can slip a liner in and haul asphalt if I need to as well. I ordered the new bed with an asphalt apron as a backup plan.
Awesome good to hear you will keep it on the road making money!
 
I took Thursday and Friday off to get another 4 day weekend to allow more time for some major steps in this build. Please remember that while I am building this truck I'm still working my 45-50 hour a week job on second shift. I have no plans to leave my employer and will stay even after the truck is complete and running.

I received the dump bed on Friday evening, I lifted the rear with my 750 Holmes wrecker and my buddy who helped remove the mixer lifted the front. It was transferred to one of my gooseneck trailers and it will stay there until I am ready to weld the hinge plate into the truck frame. At that point it will move to the truck for all of the fabrication to take place. The cab guard will have to be cut to look right with the width of the cab and welded onto the front of the bed at a suitable height to protect the cab from falling rocks and debris. The asphalt apron will be welded together and attached to the back of the bed. I will also install the front cylinder mount to the truck frame at that time. The bed will come back off after all fab work is done to be painted and installed one last time.

Photo credit goes to my dad. He is now retired but was a professional photographer his entire career.
 

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Mack springs are no joke. Much heavier and different than other makes. Nice work
Grew up around Mack’s … drove 18‘s and body load 10’s … get one in a ditch and a crane would just spin the front and then drop it like a bad habit, LoL …
But that’s not to say KW didn’t make some HD off-road units … just not as well known for doing it in the dirt.

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The new rear trunnion was also installed this weekend. This is a revised design that does not require removing all of the rear crossmembers and anything else behind it to install it. It slips between the frame rails and uses large spacers to close the gap. The hardware is much larger than original at 1" instead of 7/8" huck bolts. The first two pictures show the mounting holes being drilled out. The hardware was torqued in an X pattern to roughly 800 ft lbs. The torque multiplier was a huge back saver for tightening the bolts. It is the Klutch branded one from Northern Tool.
 

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Grew up around Mack’s … drove 18‘s and body load 10’s … get one in a ditch and a crane would just spin the front and then drop it like a bad habit, LoL …
But that’s not to say KW didn’t make some HD off-road units … just not as well known for doing it in the dirt.

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That is a C-500 if I'm not mistaken? Gorgeous truck, those oil field rigs always hold a special place with me. Sadly there isn't much oil industry where I am from so I never spent much time around them.
 
Incredible work here. I have a feeling you have much more builds in the future. Don‘t ever lose the positive curiosity which drives this and the can-do thinking.
 
Got the left trunnion bushings replaced and almost ready to reinstall. These are 3.5" ID and 3.75" OD. The brown stuff you see is excess copper antisieze that I coated the exterior of the bushings with. These are sealed by a Labyrinth seal and have a grease fitting on the outside. I will be using Schaeffer 219 Synforce Green Grease. That is what I use everywhere else and my local Schaeffer rep felt it was appropriate in these too. The custom driver was turned from a disc of 6061 aluminum and survived a 10lb sledge hammer. The bolt threads into an old piece of shafting that I drilled and threaded to 1/2"-13 to help keep things together when beating on it.
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Got the left trunnion bushings replaced and almost ready to reinstall. These are 3.5" ID and 3.75" OD. The brown stuff you see is excess copper antisieze that I coated the exterior of the bushings with. These are sealed by a Labyrinth seal and have a grease fitting on the outside. I will be using Schaeffer 219 Synforce Green Grease. That is what I use everywhere else and my local Schaeffer rep felt it was appropriate in these too. The custom driver was turned from a disc of 6061 aluminum and survived a 10lb sledge hammer. The bolt threads into an old piece of shafting that I drilled and threaded to 1/2"-13 to help keep things together when beating on it.
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**** son, you do some top of the mark work is all I can say. I always loved the style of the “R” Model Mack’s. Probably reason why dad bought his 83’ day cab R model from his old employer too 🍺🍺👍🇺🇸
 
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