I have a 1950 Chevy 1/2 ton truck with the original torque tube rear axle. As you know, the rear axle has pivots that clamp to the springs, so the axle itself isnt actually bolted down. Now, I still have the original rear axle, but Ive replaced the torque tube part with an open driveline differential out of a 62 Chevy. This means I have to find a way to clamp the rear axle to the springs so it doesnt pivot anymore. Ive heard of people welding the pivots up, but Im not sure I want to do it. I was also thinking of just using the original front u-bolt on the pivot just to keep it in place over the spring centers, then using a pair of u-bolts to clamp the axle to the springs like a modern vehicle. The only thing is that Im wondering if doing this might pivot the axle too far back and give it a weird driveline angle. I dont think it would but its something Id have to check out. So to those of you who have done this, what did you do to keep the axle in place, and what would you advise?
what the hell? why did you replace the torque tube if you didnt replace the rear end? also, how in the world does it seal on the rear end and the transmission??? ive never even heard of people putting driveshafts on torque tube axles(without a conversion kit) but to answer your question, you cut off the old mounts completely and grind it smooth and weld on a new set of solid perches. but in order to fit they need to be just as skinny as the springs, and i know those early ones were skinny. also you will need to get new u bolts that swing over the top of the rear axle.
My goal was to keep the original chassis and axles with the exception of having an open driveline, so I could go with a newer style engine and trans. As for converting it, some 55-64 1/2 ton Chevy trucks came with the same rear axle as the 47-53/55 1/2 tons, except that the differential was for an open driveline instead of a closed one. It bolts right in place of the old 47-55 torque tube differential. It must not be a well known fact since nobody Ive talked to has ever heard of doing this. As for cutting off the perches, Id rather not. Id like to be able to go back to the original torque tube and source out an Inline 6 and 4 speed if I ever so desire. Edit: But what you are describing is similar to what I want to do, except instead of cutting and welding on a new perch, I would just reuse the old perch, but still clamp the axle to the springs with new u-bolts. Basiclly, the new u-bolts would keep the axle from pivoting on the perch.
well i dont really see a safe way of doing it other then what i described. but anyway, i did not know that bit of info, pretty neat! a lot of guys change the rear ends just for the fact they cant have the torque tube. i will have to refrence this myself and maybe go dig some out of the junk yard for a later date....
My next door neighbor did the same conversion of parts that you have listed. He had the pivot area on the spring mount welded up by a welding shop. I have in the past used a heavy walled square tubing as the metal stock to build the narrower spring perches, when the already to weld on perches are too wide for the application. P.S. Be sure to set the pinion angle at around 2 degrees (diffential installed and weight of truck on rear tires), before tacking in position and then welding up the pivots.
One other thing I know I would have to watch for if I put new perches on is that the axle would then sit too far forward, I would need to make up a plate also to move it back. Here is a real quick sketch of what I was thinking of doing: As you can see, the original front u-bolt still holds the perch/pivot onto the centering pin as usual. The original rear u-bolt is removed, and instead 2 larger u-bolts go around the axle and clamp to the springs, holding the axle tube to the springs, taking the place of the original rear u-bolt, and also keeping the pivot from pivoting. Any reason why this wouldnt work?
The 55-64 was bolted on like a modern axle. They just used a differential that seperated from the housing.
watch that pinion angle, here is a $13 solution. don't do this. almost every truck for 50 years used the same design at the leaf spring. think about it.
I understand the concept, but would worry that there is alot of pressure in a very small spot on the lower axle housing whereas if the perch is welded on, it diffuses the pressure to a greater area. just my 2 cents.
You are way, way, way overthinking this. Just make some spring pads with the spring bolt hole where it needs to be to locate the wheels in the center of the wheel opening, carefully cut the existing brackets off your axle housing, and weld the new pads on. If you ever want to go back to the torque tube (?) at some point, cut the pads off, weld the old brackets back on. Brian
the jegs ones are too wide (made for a 2.5" spring i believe), currie has 2" and even 1.75" in 3 and 3.25 axle tubes but remember, the axle will be about 1.5-2" forward of center IF you don't redrill the centering hole..
If you insist on using the original rear end housing then you have four options as I see it. Weld on new spring perches, weld up the spring pivot, install ladder bars, or attach it as your drawing except there needs to be some sort of spring pad under the axle housing to maintain the correct pinion angle.
You can rig it up somehow or just bite the bullet in two ways. Weld on a proper set of perches and be done with it or create a torque arm for the center (beside the driveshaft) that approximates the original torque tube and keeps the axle from misaligning. Me...If for personal reasons the stock truck held an important place in my heart, I'd modify a different axle housing by welding on perches, (maybe the 62 that you pulled the diff from?) and put the original axle that you have into storage for safe keeping.
I just sold a chassis that had the original rear axle pumpkin swapped out for the later open drive pumpkin.This chassis had an adjustable link on each side of the axle similar to a ladder bar setup so you could use the original perches and adjust the pinion angle.
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