Good healthy carnage

[ahart]

Angle cylinder pin broke on D6N and they shoved the rod through the back side of the blade. Don’t know where they get these guys.

 

[Truck Shop]

Don’t know where they get these guys.

Look at all the money these guys generate in repairs, it's built into the work force, they keep
the mechanic/welder trade busy. Without them everyone on here would be busy carving out
a wooden bill so they could peck sh!t with the chickens.

 

[Nige]

785D Haul Truck - 125 hours from new. Final drive let go and locked up. The truck was loaded and stuck right in the middle of a haul road at the time.......
IIRC correctly it was a bolt from one of the 2nd reduction planetary shaft retainer plates that fell out and went through the gear train. CORRECTION: It was a 2nd reduction bearing failure by the looks of it.
Basically the boys went in the housing with a shovel and dug out the debris.

 

[Nige]

Photos Part Deux

 

[Truck Shop]

Photos Part Deux

What's a rough estimate for repair of that on a out of warranty machine?

 

[ahart]

I wish I still had pictures of the D11R I had to cut the planetary carrier out of it to get the axle shaft out to pull the final. That was the worst exploded final I ever came across.

 

[Acoals]

A problem built into air disc-Heat. The cavity where the seal is small plus the rotor is tucked inside
the drop center of wheel. Which allows for very little cooling through the rotor veins. Depending
on brake usage the seals cook, especially the National type OEM. Air disc works in some applications,
out here in many cases trucks are spec'd with disc on the steer drum on tag and drive. My experience
with air disc-it's definitely not cost effective in a fleet-OO maybe.

So what is the benefit of disc? Isn't heat dissipation the point of disc?

 

[ahart]

Truckshop- a reman final and brake group for that 785D is pushing 90k, no telling what they’d charge in add bills or core value deductions.

 

[Truck Shop]

So what is the benefit of disc? Isn't heat dissipation the point of disc?

NHTSB--stopping distance-which is really negligible in the real world, not on a test track.
Trucks are not required to have air disc, but many jumped on the band wagon with sales pitch.
Problem is the thinner the rotor gets the faster it heats. Drums have x amount more
friction surface and a open cavity for air, Disc doesn't do well in stop and go traffic.
*
The real benefit of air disc is the manufacture keeps your wallet vacuumed, a complete brake
replacement with disc on a three axle tractor can hit $8,000. Drum $2,000.

 

[Acoals]

NHTSB--stopping distance-which is really negligible in the real world, not on a test track.
Trucks are not required to have air disc, but many jumped on the band wagon with sales pitch.
Problem is the thinner the rotor gets the faster it heats. Drums have x amount more
friction surface and a open cavity for air, Disc doesn't do well in stop and go traffic.
*
The real benefit of air disc is the manufacture keeps your wallet vacuumed, a complete brake
replacement with disc on a three axle tractor can hit $8,000. Drum $2,000.

Sounds about right. The Fed will be mandating that soon enough . . .

 

[Truck Shop]

Truckshop- a reman final and brake group for that 785D is pushing 90k, no telling what they’d charge in add bills or core value deductions.

I was seeing major dollar signs. Thanks for answering.

 

[Truck Shop]

Sounds about right. The Fed will be mandating that soon enough . . .

Well people are finding out and in some cases, dropping the disc and going with drum. I put a stop to it
a two years ago. I told him not to buy them in the beginning.

 

[Nige]

I wish I still had pictures of the D11R I had to cut the planetary carrier out of it to get the axle shaft out to pull the final. That was the worst exploded final I ever came across.

I’ve seen a few haul truck finals that had to be gas axed apart to get the guts out. Last I heard Reman 793 finals were going for $200k a copy not including the Core Charge Credit, trash one and it would probably be upwards of 250k.

 

[Truck Shop]

I’ve seen a few haul truck finals that had to be gas axed apart to get the guts out. Last I heard Reman 793 finals were going for $200k a copy not including the Core Charge Credit, trash one and it would probably be upwards of 250k.

Holy Moly.

 

[Nige]

Last fleet I worked with were 785D, small by mining standards, only 150 ton payload. A planned component replacement at 18k hours for everything in the power train from the radiator through to the final drives, steering overhaul, suspension, & dump body cylinders came to just short of $1m a copy in parts. We had 35 trucks and basically at any given time one of them was going through that process.

We could turn one round in 30 days, so 12 trucks a year. With each truck working on average 6k hours each year the math worked out perfectly.

 

[Acoals]

Last fleet I worked with were 785D, small by mining standards, only 150 ton payload. A planned component replacement at 18k hours for everything in the power train from the radiator through to the final drives, steering overhaul, suspension, & dump body cylinders came to just short of $1m a copy in parts. We had 35 trucks and basically at any given time one of them was going through that process.

We could turn one round in 30 days, so 12 trucks a year. With each truck working on average 6k hours each year the math worked out perfectly.

Two curious questions; What were those 785d's new, and how many times would you overhaul them like that before it wasn't worth it?

 

[Nige]

About $2m a copy. Planned life for them on that job was set at approximately 90,000 hours, so 4 overhauls from new then scrap.
EDIT: The life expectancy of any mining machine is dependent on the life of the chassi/frame because everything else is a bolt-on, even stuff such as cabs.

 

[Tyler d4c]

Last fleet I worked with were 785D, small by mining standards, only 150 ton payload. A planned component replacement at 18k hours for everything in the power train from the radiator through to the final drives, steering overhaul, suspension, & dump body cylinders came to just short of $1m a copy in parts. We had 35 trucks and basically at any given time one of them was going through that process.

We could turn one round in 30 days, so 12 trucks a year. With each truck working on average 6k hours each year the math worked out perfectly.

I got bored doing certified power trains at the cat shop I worked at after 2 or 3 months id probably be looking for more exciting work

 

[OzDozer]

Maybe 20 years ago, I saw a D10 that was absolute scrap after 22,000hrs of working on iron ore.
Never seen a tractor with so many weld-on patches on components such as track frame, and even the main frame.

 

[ahart]

Side note on rebuilds, it may no longer be worth it on the site it’s on but we’ve moved plenty of 793 trucks across the US to a different surface strip job where they were put back in service and reframed with over 100k hours on the frames. When I left that strip job, they were exchanging engines/torques at 21k-22k hours in a 793C. As the budget gets tighter due to coal demand going down, those hours get pushed more and more. We would almost always swing a 3508 in a D11 at 12,500 hrs no matter what but I’ve heard they are pushing them to 15k or more these days and just rolling the dice on the core. And Nige is 100% correct, on a job that size there’s always a 793 and a D11 getting an engine changed. Seems like we did very few of them in the shop too, most were done outside in the parking ditch.