1957 Commercial chassis

Started by Cymz@sbcglobal.net, March 07, 2020, 10:34:16 AM

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Cymz@sbcglobal.net

Hello, I recently purchased a 1957 Cadillac Superior that has been converted to a camper.  I am looking to update the entire underside of the car as it has been sitting a while.  I have heard that the rear ends are problematic and was first wondering if anyone has updated to a newer rear end.  Also, doe anyone know of an affordable  source for all the bushings, steering, and suspension components?  I think a front disc brake conversion would be a good update as well but has anyone done one of these and if so how did you source the parts?  I have not even gotten the car back from its current home in Canada yet and am posting this on anticipation of picking it up in April.  Thanks in advance

Cadman-iac

#1
Does your car have a leaf spring rear suspension,  or the coil and link design? Being a conversion, it's probably going to have leaf springs. It also may have an entirely different axle than what Cadillac would have used for a conventional car because of the weight of the camper. Are there single or dual wheels in the rear?
That makes a big difference in the ease of conversion.  My 56 has leafs, and I just took an axle from a 72 Coupe Deville, trimmed off the coil/link style brackets, and welded on new leaf spring perches.
That also gave me a newer design axle as well as better brakes.
For a link style suspension, you will have more work setting it up if you want to keep the original suspension components.
Otherwise,  you can get an aftermarket set up of your choosing for both the axle and the suspension.
  If it does have dual wheels on the rear, a good choice of axle for a replacement is the 14 bolt GM one used in a 1 ton truck. The older ones came in two widths, an 8 foot, and a 7 foot wide. I've got the 7 foot one in my '64 1 ton Flatbed Chevy.
There's also an Eaton axle that GM used from the '50s through the 70s, and the easiest way to identify these is the "pumpkin" unloads from the front. On the later 14 bolt, 10 1/2" ring gear axle, it has a  cover on the rear that everything is accessed by. Either one is a good choice, they both use a full float wheel hub, meaning that the weight of the vehicle is not carried by the axle shaft,  but by the wheel hub and bearings. There's two bearings per side, instead of just one like the typical car would have. Also,  both of these have a third pinion bearing like a Ford 9" does.
One drawback to the Eaton axle is the availability of replacement gears. Some of the ratios are not out there even used anymore.
With the GM 14 bolt, you can still get gears and bearings without any problem.
Also, if your camper has just one wheel per side, you can still get both an Eaton and  the  14 bolt axles, and they both will have the full float hubs. The hubs just have a different shape and shorter wheel studs. The dually's hubs are deeper to get the load centered on the hub with 2 wheels, and they have longer studs.
There is a similar axle with 14 bolts on the rear cover, it's a 9 1/2" ring gear axle, but it's only got 1 bearing on each side for the wheel, and the hub does not extend out beyond the drum like the full float ones do. Those are typically found in a 3/4 ton truck.
If your original axle is a 5 bolt wheel like a car would have,  swapping for a truck axle means you would need two spare tires then.
But that's all I can offer you in the way of choices. My experience with swapping Cadillac axles is limited to this one car.

Hope this helps a little.

Rick
1956 Coupe Deville A/C car "Norma Jean"

Cadman-iac

Here's a couple pictures of a narrow (7') GM 14 bolt dual wheel axle. The cover and the hub for identifying them.
1956 Coupe Deville A/C car "Norma Jean"

Cadman-iac

#3
This is the 14 bolt semi-float axle used in 3/4 tons. Note the difference between the drums and hubs. This one also only has a 9 1/2" ring gear,  whereas the full float axle is a 10 1/2" gear.
1956 Coupe Deville A/C car "Norma Jean"

Cadman-iac

#4
And finally, this is an Eaton axle. It's got a cover on the rear just for inspection and access, but the gear assembly comes out from the front.
Another feature found on some of these is a "thrust button" for the ring gear to try to keep the deflection down when there's a heavy load on it.(Last picture).
One big problem with these axles is that the pinion bearing is really hard to find anymore, and there were two styles. Both come as a unit with the front and rear bearings using a common close coupled  inner race assembly, and separate outer races. However, the earlier version had ball bearings, the later one used barrel style roller bearings.
The last one I did, I just had to use the best one I could find, as there were no new ones available anywhere. I can't remember which style that one was now, and I don't know if any new ones exist anymore.
That's something to consider when choosing a replacement axle.

The middle picture is of two different years of Eaton axles brake drums. The right one is out of a '68 3/4 ton, and the left one is a 3/4 ton from the 50's, not sure of the year.
1956 Coupe Deville A/C car "Norma Jean"

Cadman-iac

If anyone thinks that I give out too much information, let me know and I'll quit doing that.
I personally feel that the more you know, the better choice you can make. I've faced many decisions without benefit of someone else's knowledge, and I can tell you that TRIAL by ERROR  sucks!
Plus,  it's a habit that I got into from being asked many questions as a parts man. Not an excuse, just an explanation.

Just my humble opinion.
  Rick
1956 Coupe Deville A/C car "Norma Jean"

Cymz@sbcglobal.net

thank you for the response.  I used to build large 4x4 trucks so I am familiar with the 14 bolt.  It has single rear wheels but the hub actually looks like it should be a dually I am told.  Once I get t home I can see what is all underneath it.  I do want to stay with the standard 5 lug if that is what it currently has  thanks again

Lexi

Your info and details in explaining things I think is pretty good. No complaints here. Clay/Lexi

Cadman-iac

#8
That's interesting, but not surprising.  My dad had a motorhome back in 73 with the van nose, a class "C", and it had the single wheel axle. It held up the vehicle,  but it was really hard on tires. We used to say that it had square tires on it,  because if it sat very long in one place, it would get flat spots and until the tires warmed up, it rode like a freight truck.

It's too bad that they didn't make a dual wheel that would work with a 5 lug pattern, or some sort of adapter so you would only need one spare.
But it doesn't look like it's so big that just one wheel wouldn't work, as long as you use a really good tire.
It will be interesting to see what the wheel looks like. If you get the chance, I'd like to see it.

Great find!
1956 Coupe Deville A/C car "Norma Jean"

Cadman-iac

Quote from: lexi on March 08, 2020, 12:16:26 PM
Your info and details in explaining things I think is pretty good. No complaints here. Clay/Lexi
Thanks Clay, I  appreciate that. And I can say the same for you. You have been a big help with my own car. Thank you.

Rick
1956 Coupe Deville A/C car "Norma Jean"

Lexi

You are most welcome Rick. I think the digital age has impacted how people communicate and not always in the best way. When in doubt, a picture is still worth a 1,000 words. Clay/Lexi