The Stovebolt Site Forums The Shop Area General Truck Talk '39-'55 front axle swap

I'm working on a '39 3/4 ton. The front axle has "issues." I have located a '55 6 bolt unit. What kind of problems will I encounter putting the '55 onto the '39 frame?

I have done a lot of searching, but came up empty handed. Any info will help.

Thanks

Gary

The 39 3/4 ton axle is the same as the 39 1/2 ton. 1/2 ton axles should be straight bolt in through 1954. Not certain about 1955. Did they change the track?

Don,

Near as I can tell, the spring eyes are longer. I'm still trying to determine the eye to eye distance between the springs, and the hub to hub distance...or king pin to king pin.

Any info helps.

Thanks

Gary

should be able to find all the dimensions in the resto packs here - none listed for 39, but 40 should be the same as, and for the 55, the 1st and 2nd series will be different .... I'd expect the 55 to be quite a bit wider

Bill

Squeeze,

I'm checking it now.

thanks

GAry

Don't know about the springs, just the axle. I had what should have been a 51-53 front axle. It would have bolted right into my 39 3/4 ton. Different spindles, king pins, brakes, etc., but same track.

Don, Squeeze,

I'm downloading from the Heritage site, but it takes time. I'm still on dial-up. Apparently, there is a big difference between fist and second model '55s. I have to sort that out, and I have find out if the axle is from a 1st or 2nd. I have not seen it, and I am not close to it.

Thanks,

Gary

To all who are curious,

I am finally getting the info downloaded where I can read it. While a confusing mess, it appears that there is very little difference between the '39 and the '55 1st edition. The late model '55s have 2 inch springs as opposed to 1 3/4; the springs are much longer eye to eye (36" vs 44" I think), and the wheel base is several inches wider. Many differences. The spindles appear to be the same on both 55s, but different from the 39, outside bearings are the same, but inside are different. I have to re-read on the king pins.

So...an early 55 probably will work for the 39. The late model, or 2nd edition, would cause a lot of headaches, and probably put the tires into the fenders.

However, I would still appreaciate hearing from someone who has done the job.

Thanks,

Gary

OK, to all involved, It was a grand plan but it didn't work. The axle in question is from a 2 series '55, and doesn't easily attach to the '39

Merry Christmas to all.

Gary

I tried to verify that the '39 ¾-ton and the ½-ton have the same part # in the 1929-54 MPB. According to the book, a ½-ton is a series JC, a ¾-ton with 11" brakes is series JD and a ¾-ton with 14" brakes is a JE.

I cannot find an axle listed specifically for these models but I do find one for '34-40 Comm. and another for '41-54 ½-ton. From that I'd say Gary needs to find a '34-40 axle for a bolt in replacement. The '41-55.1 may be usable with some mods.

Gabster,

Yes, it's confusing. I pulled down all the specs I could find, and it does appear that the axle up to '54 should bolt to the '39 frame. It also seems that the 1st series '55 can be used, but may need some slight mods. I will continue looking for a 46 to 54. There has to be one someplace in the southern end of the state. When I find it, I will roll the dice, take it home, and see what happens.

Again, it appears that the outer bearings are the same, but the inners are a bit larger on the newer models. The pins appear to be the same, but, when they go from reamer fit to floating, there may be a change. Don't know about that one, but it's academic if I am using an axle/hub set from the same year. The brakes go from 1 3/4 to 2 inches, but that may not change the tread width. There is room in the 1 3/4 drums to increase them a 1/4 without changing the stance.

I guess it if was too easy it wouldn't be fun??

Thanks for your efforts on digging out the specs.

night

Gary