1957 DeSoto 8 3/4"

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JGC403

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Here is what we are working on:

First is a 1957 DeSoto that we are finishing up to get her back on the road. Part of that is disc brake conversion front and rear. Right now we are replacing the old leaf springs with new ones from ESPO. Since the rear is out I want to upgrade it and do the disc conversion now. There is nothing available for the stock tapered axle shafts. So can I convert the stock 8 3/4 to a flanged axle shaft? I want to retain the tapered roller bearings. I know the stock rear uses shims to set the end play, so it would have to be converted over to the later threaded adjuster. Does anyone know if this is possible?

I don't want to trow the DeSoto 8 3/4" away so If the above won't work can I shorten the DeSoto 8 3/4" to fit my 1968 Barracuda and install new Moser Axle Ends. I want to use tapered roller bearings and a flanged axle shafts with that set up as well.

Help.
 
You would have to change the axle ends to make the Flange axles work. I would find a latter model, maybe a 68-70 B body 8 3/4" rear housing? I don't know what your rear housing measures.
 
You would have to change the axle ends to make the Flange axles work. I would find a latter model, maybe a 68-70 B body 8 3/4" rear housing? I don't know what your rear housing measures.

Roy is correct. The axle housing ends need to be cut off and the correct ones welded on. This is a very simple, straight forward procedure, even if not done yourself. Very affordable to pay someone to do, so don't let it deter you from doing this.
 
Yes plus you will need axles and install the thrust button in the carrier if it will accept them.
 
Roy is correct. The axle housing ends need to be cut off and the correct ones welded on. This is a very simple, straight forward procedure, even if not done yourself. Very affordable to pay someone to do, so don't let it deter you from doing this.

Are the Moser end that I posed in post #3 the correct ones?
 
Are the Moser end that I posed in post #3 the correct ones?

I believe so, yes. But call them to be sure. Just tell them what you have and see if those are correct. I am almost positive they are.
 
I have never worked on the older non flange rear ends, so sorry if this dumb. Can you remove all the drum stuff and use the stock hub with a disk brake kit? Keeping the stock axle ends, bearings, and hubs?
 
I have never worked on the older non flange rear ends, so sorry if this dumb. Can you remove all the drum stuff and use the stock hub with a disk brake kit? Keeping the stock axle ends, bearings, and hubs?
That I have never done. Chances are your going to have to call the Disc brake kit manufacture.
 
I bought a truck bed trailer with one of those old tapered axle rear ends. The guy had torched off all the brakes because they were stuck and he didn’t have the means to properly remove the drum. It looks like disk brakes could be added just like it is... if you found a rotor that could slide on and fit right, along with some kind of caliper bracket welded to the housing. A guy I know does that kind of thing with Dana 60s in his rock crawling rigs.

There probably is no kit, you would need to fabricate and modify everything.
 
It would be easier to convert it to flanged axle shaft. With the stock tapered shaft the wheel studs are in the drum. The axle shaft has a key way and the drum is an interference fit with the tapered axle shaft the key just keeps if from slipping and a nut with a cotter keeps everything together. Flanged axle would be stronger to. I don't think its worth messing with the old tapered shafts.
 
It would be easier to convert it to flanged axle shaft. With the stock tapered shaft the wheel studs are in the drum. The axle shaft has a key way and the drum is an interference fit with the tapered axle shaft the key just keeps if from slipping and a nut with a cotter keeps everything together. Flanged axle would be stronger to. I don't think its worth messing with the old tapered shafts.

I agree.....and cheaper still than paying stupid ridiculous prices like some of these folks around here for an A body 8.75, for example. 1K bucks is the going asking price. I bought a Dana 70 for 100 bucks. DEELIVERED. lol
 
Depending on how wide your housing is you could put new ends on and set it up for stock lenght B or E body axle shafts.
 
We had a 57 Plymouth back in the day. We used an 8 3/4 out of a 69 Furyy III. IIRC, it bolted right in.
 
I’m changing the axle out in my tapered axle in my 64 truck. There’s nothing wrong with the setup except I don’t think you can get drums. I have the old tools and have worked on the 57-64 diffs. My research yielded no way to go to disk without custom modifications. I was lucky because the 65-71 is the same width. Now I'm disk ready with off the shelf stuff. You need to measure and check the charts because there’s probably something the same width. Post up the width. My 2 cents. Craig
 
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So I'm going to rebuild the center section that came out of the DeSoto 8.75. The casting numbers on the case end in 983, i think its basically the same as a 741 center section. If I buy a rebuild kit for a 741 should everything fit the 983?
 
I Think ur right. But to be sure u could take the diff apart and get all the numbers from the bearings and races. Kim
 
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I Think ur right. But to be sure u could rage the diff apart and get all the numbers from the bearings and races. Kim

That is a good idea.

Alright one last question as of now anyways. I'm using 1965 C-body housing and axle shaft and the 1957 DeSoto center section. It looks like the thrust block in the differential is different width or the 1965 axle shafts are slightly longer compared to the DeSoto axle shafts. So could I cut a little off the axle shafts or is there a different thrust block to put in the differential? How much clearence should there be between the axle shafts and the thrust block?
 
I know a fella out here that sells a disc brake conversion that uses stock spindles and a homologation of parts off chebbies n such.... if he is still alive, i have his number.
 
That is a good idea.

Alright one last question as of now anyways. I'm using 1965 C-body housing and axle shaft and the 1957 DeSoto center section. It looks like the thrust block in the differential is different width or the 1965 axle shafts are slightly longer compared to the DeSoto axle shafts. So could I cut a little off the axle shafts or is there a different thrust block to put in the differential? How much clearence should there be between the axle shafts and the thrust block?

To clarify. This 65 cbody housing is flange with the 5 bolt holes? You’re using the correct backing plates and axles that came with it. If so, you shouldn’t need to change anything. Just put the chunk in.
 
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To clarify. This 65 cbody housing is flange with the 5 bolt holes? You’re using the correct backing plates and axles that came with it. If so, you shouldn’t need to change anything. Just but the chunk in.

Correct. 1965 C-body housing, 1965 C-body flanged axle shafts, 1957 DeSoto center section, I'll be converting it to disc brakes.
 
I believe the block in the 1957 set is only 1 inch wide. I could be wrong though. The clutch sure grip the 2 pins measure 1 3/8ths. The newer open and cone type it is CX 1 1/2 wide. I have had axles shortened 1/4 in each side with no ill effects. U won’t have to shorten the 65 axles as the block isn’t as wide as the 65 up blocks. Do a measurement to be sure. Kim
 
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