So, I'm new to the Tons 'o fun group. I just picked up a 1951 GMC 250 dump truck and was told it is a 1 ton so here I am. Was told it ran when parked. Somewhere during it's life it received a 1962 261 chevy engine with the 12v electrical. I gave the fan a push and a pull and it seems to be free. soo now begins the project....along with the 1953 chevy 3/4 ton I've beem slowly bringing back around.
So my 1951 GMC 1ton has a big 5 lug pattern on the rear dually wheels, I've never seen this before, usually there are at least 8 lug. Don't supose any of you would happen to know much about this type of axle? possibly if someone out there has been able to track down brake parts for this type of setup. I've read a few posts about possibly having to have my hardware re-shoed, figured I'd ask around just incase someone has found some brake shoes redily available.
Regarding the red GMC pictured above it looks like a 1 ton by the front bumper and front axle. Rear wheels with 10 lugs at 7.25" bolt circle would be an axle from a 1.5 or 2 ton and would physically bolt in with the springs from the larger truck too. That size bed with even a half load of gravel looks like more than enough for a 1 ton.
Now I'm less sure what your rear axle is. I was thinking it might be 10 lug which often uses 5 of those same bolt pattern on the front in GM applications.. but that's not what you have.
Some 40's GMC's I think used 5 lug which might be what you have, and it may be more like a 1 ton axle. 48-53 GMC 1.5 ton sometimes had 5 lug "Motor wheels" which might be what you have. If 20" rear tires I'd suspect an axle larger than 1 ton. In any case it is not likely original to the 51 GMC you have. Might not even be from a GM truck. Post some more pictures of the axle and perhaps someone will know more. I think you can post more pictures in a reply.
1 ton and 3/4 ton front axles for 48-54 are somewhat the same, but also not. The axle beam is the same forging. The 3/4 ton uses 1.75" wide springs and the 1 ton has 2" wide springs, so the U-bolt holes are drilled appropriately in each axle for the springs. The hubs if single wheel are the same, 3/4 ton did not have dual wheels. Brakes on the 1 ton are larger than the 3/4 ton, so different drums, backing plates, shoes, and stuff. Spindles are the same, and I think but not sure on the steering arms.
