Michigan 675 wheel loader project

[Arc weld]

I believe the tires were specially made for the 675 and were the largest tires in the world at the time. They were 10' in diameter but didn't have a very long lifespan. I think better tires came along later. Looking at pictures of the 675, they had much wider tires than the the prototype. The 14 production machines were built between 1973 and 1976. I don't know when the 2 were bought back and rebuilt as C models. The International 580 came out in 1971 and was also a big loader. 18 yd's later upgraded to 22 yd. It used a single engine. It had a much longer production and evolved into the Haulpack 4000 with 24 yd bucket and lasted till 1996. The Letourneau L2350 is the biggest loader now and has a standard bucket of 53 yd's!

 

[Renze]

for what reason were the B models rebuilt as C ? the B series had twin Detroits and the C had Cummins ?

 

[Arc weld]

A must have been the prototype model(s) with Detroit engines, no cab, no roll bar. You would definitely need hearing protection with 24 cylinders of screaming Detroit behind you! The B models were the production models with Cummins engines. Possibly to renew interest in the 675 is why Clark bought a couple back and added similar refinements and improvements to them as the smaller C series loaders. I would think with all the development costs, the 675 was a big money loser for Clark, although from watching the old Clark videos, the 475 and smaller loaders were a great success. Some have speculated that the 675 may have been ahead of its time.

 

[Renze]

You would definitely need hearing protection with 24 cylinders of screaming Detroit behind you!

The company i work(ed) for till december 31th, used to put Detroit Diesels in wheel loaders too, on customer demand. (standard was a DAF engine, which is the predecessor of the Paccar MX)
Of the older 70's ones, only those with Daf engines are still around, the ones with Detroit are rare (for obvious reasons). The servicemen remember that when they had to do a 500hrs service at the quarry, even two 6-71's (in little 17 ton loaders) were deafening...

anyways, it seems they built a fair bit of 475s in a couple of years, if you believe the videos... But the 675 was double the size of the 675, maybe they overstepped that a little... in this size, all components have to be purpose built, so i understand their way of thinking that you cant offer as wide of a size spectrum as in the high sales volume class...

 

[Arc weld]

Don't know why more weren't sold, maybe customers didn't like the dual engines, limited tire life, too costly, etc.? 475's were quite popular though and lasted through the C series. I remember they had an optional turbo transmission with a 10,000 hour warranty. The Hough (IH) 580 wasn't much smaller but versions of it were around till 1996. I don't know how many they sold though. There's been other big loaders and machines built that also seemed to be ahead of their time that are now surpassed in size. The O&K RH300 is example. It is small compared to mining excavators today but when it was built was the biggest in the world by a good margin. Only 3 were built.

 

[Renze]

Don't know why more weren't sold, maybe customers didn't like the dual engines, limited tire life, too costly, etc.?

i guess the remote torque converters (a pump wheel at each engine, feeding a common turbine on the transmission input shaft) cant be that fuel efficient either...