Mack B Series Trucks

Mack1a.jpg - 8.3 K
Mack B series
Mack1a.jpg - 8.3 K
Mack B series

This Mack joined our fleet to replace the SF180 Cornbinder. The Cummins 220 was much more powerful and the 10-12 yard box would hold half again as much rock. This oversized box probably lead to the ultimate demise of the truck, but not before it moved a lot of rock around our place.

In the 1950's and early 1960's Mack made the B series trucks. The Cab design came straight out of the 1940's. Unlike the cabs of freight trucks today which tend to be large, this cab you wore like a pair of pants. It was about the size of a pickup cab of the era. The Mack shown here is a very classic Mack truck. Mack has historically made more of the truck than any other manufacturer in the US and this truck was no exception other than it had a Cummins 220 in it instead of the traditional Mack Thermaldyne. This model was about a 1960 model, and by them the popularity of the Mack engine had declined somewhat because the Jacobs Engine brake was available on the Cummins but not the Mack engine, and the Cummins had a bit more power.

Of course, this truck did not have a Jacobs brake, but rather had a "Blue Ox" exhaust brake. Unlike the slide gate exhaust brakes of today such as those on the Military truck featured elsewhere on this site, the exhaust brake on this truck was of a butter fly valve type.

By the time we acquired this truck around 1980 it had spent many years on an Indian Reservation where it had acquired over 700,000 miles on it. the cab had shaken so much that there were fatigue cracks in the dashboard and the doors needed bunge cords to keep them closed. We used this old girl off highway so those cosmetic problems were not of direct concern. Indeed it was my first diesel dump truck. We had lots of logging roads to rock and this was actually the 3rd of many trucks that I used to accomplish the task. It all began with a single axle flatbed and moved to the IH SF180 shown elsewhere on this site. The End of it was when the frame no longer held together.

The transmission was a classic Mack quadraplex. This was a 5 speed box bolted directly to a 4 speed box. The gearing was 250 RPM apart all the way from barely moving to the truck's top speed. The minor shifts (second box only) could be easily made with or without the clutch by just adjusting the throttle a bit. Major shifts (up in one box and down in the other) where harder, but still could be done much easier than with most transmissions. Unlike the remote brownies which tend to have linkages that you have to chase all over creation, the brownie on this transmission ha a very short stroke (and a long handle). The tandems were also of the traditional Mack Camelback variety, where the spring doubles as the walking beam. The Manual steering was somewhere around 9 turns from lock to lock, and on crooked logging roads you really had to learn to spin that wheel, and I left a few creases here and there in trees where I didn't spin fast enough.

The beginning of the end for this truck was when the rear part of it upset. Pictures of that appear on the Link page. Oh to be sure it recovered from that fiasco, but this model had only a single frame and within the year after the upset the frame began to give way in the middle, Not sagging as you might think but slapping from left to right. The truck had always been a bit of a pain because warn bushing in the tandems allowed the rear end to wander, but when the frame started flexing excessively, you couldn't keep the back of the truck on the road. You would drive the front of the truck down the road, but if one side or the other of the logging road was a bit soft (and what logging road isn't--you would be out hauling rock if it didn't need it) the back of the truck would drive off the the road. Examination revealed that the frame was such a broken up mess than we really couldn't figure out how to fix it, so this truck when into the junk even though it still ran fine.

- - Updated 01/20/2013
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- - Updated 9/05/2005
- - Updated 03/27/2008