1955 LTH , The adventurous sister .

[1961H67]

Yes the transmission and rear ends are original, 10 speed Duplex with a divorced 3 speed Brown Lipe auxiliary transmission, lol , direct and overdrive . When I was talking to Wayne Hyatt about it, he asked if it still had the “ Brownie Box “ the way his Dad ordered it. And it would have had a drive shaft emergency brake, with a lever between the seats and a drum on the back of the transmission. I have no clue if that spring brake system was a aftermarket truck item or something from a off road vehicle,, it’s worked well for probably 60 years,, They had no worries about DOT or weight scales up there,, I think they had my drivers license number memorized at the westbound scale on I85 coming out of Charlotte with my Western Star! 

 

 

 

[Geoff Weeks]

I think spring brake was the only requirement that was made "retro-active" meaning any tractor had to be fit with them even if they didn't have them at the time it was built. Most requirements allow for "grandfathering" so if the vehicle was built to the regulations at the time of mfg, it didn't have to conform to newer regulation. AFAIK Spring brakes are the only exception to that.

Again, from what I remember reading, the Tru-stop driveshaft disk brake met the stopping distance requirement but not the self applying requirement of the spring brake law.

I can't remember if the spring brake law only applied to tractors or if it included straight trucks over a set GVW. 

I know I have seen plenty of straight trucks with a mechanical driveshaft brake over the years, but more recent ones used a hyd over mechanical on the front of the diff for lighter trucks without air brakes. 

[1961H67]

Good thoughts, I’m not sure when that became law, My 61 H Model had a driveline brake when I got it in 1995 , and they used it to move a 175 IHC loader for years before I got it ,,,but here in NC they were just state inspections , the federal inspection did not have to be done until about 1990 because I let my NC certificate go dead after that . Our 65 C Mack has a setup like the LTH but uses long rods instead of cables,,, Probably like you said,when they passed the law in the 60s there were several aftermarket companies making spring brake conversions.