Rear Axle Drum Offset

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ECVJeeps
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Rear Axle Drum Offset

Post by ECVJeeps »

I am about to paint and install my rear axle on the frame.However when I fit the rear drums on the axle they seem to sit out too far. It seems that the axle shafts are sitting out from the axle housing a bit far.
I have looked here for information on a correct dimension that the axles should be from the rear backing plate with no luck. I have checked the download section and the only thing I could find about the rear axle is how to clean and re-assemble the springs.
Here is a pic.

Image
Image
Image

The brake drum just covers the shoes and that is all, there is a gap from the edge of the drum to the backing plate.
What did I mess up guys?

Pat
1952 M38CDN (in progress)
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jam51m38cdn
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Post by jam51m38cdn »

Did you by chance install new hubs on the old tapered axles?
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ECVJeeps
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Post by ECVJeeps »

Never thought of that one, maybe I will have to try some of the other hubs I have laying around in the shop.

Thanks, I will try some tonight.
1952 M38CDN (in progress)
1942 GPW 51859(in waiting)
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jam51m38cdn
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Post by jam51m38cdn »

If I`m not mistaken there is a different taper on the new hubs than the old ones and you have to replace the axle as well so both match. I think I read that somewhere but I`m not 100 percent sure. Jim
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Post by ECVJeeps »

All my axels, drums, and hubs are take-off's from original M38's.
Nothing is new, the drums have been turned, the axels and hubs have been cleaned to remove any dirt or rust.
I thought that all the jeeps had the same taper to match axel and hubs?

I must have something else out of wack, I will check further tonight.

Thanks
1952 M38CDN (in progress)
1942 GPW 51859(in waiting)
M100 CDN #0548(in progress)
M100 CDN #0281
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ECVJeeps
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Post by ECVJeeps »

Here is a question, in the manual TM 9-1804B page 144 fig. 88 they show item "E" as shims, part #7374982.

Image

The two shims look different, the hole in the center looks smaller on the outboard one. Is one not a thicker plate that retains the bearing race or cone in the end of the axle tube, or is this job done by the backing plate itself.

My memory is not quite as good as it once was, but I seem to remember a thick (almost 1/8"-3/16") plate along with the shims in this location.
That would or should move my backing plates outboard and allow my drums to sit a bit further over my shoes and under the lip of the backing plate.

The image in the download section of this site is much clearer.
1952 M38CDN (in progress)
1942 GPW 51859(in waiting)
M100 CDN #0548(in progress)
M100 CDN #0281
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jimm
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Post by jimm »

You are correct and TM 9-1804B contains an error. The parts manual, ORD 9 SNL G-740 has the parts correctly labeled as Shim and Retainer in Fig. 11-4, p. 229. "Shim" is really multiple shims as neededto get the bearing freeplay correct, options listed on p. 234. The bearing retainer is listed on p. 233.

TM 9-8014B is really weak on the rear axle section. TM 9-8012 (Maintenance) covers it better.

Did you replace the bearing cones on the axles? Did you get them on all the way? If not, that would make the axle end stick out too far.
Jim McKim
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Slowly turning rusty parts into OD parts
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Post by Cacti_Ken »

jam51m38cdn wrote:If I`m not mistaken there is a different taper on the new hubs than the old ones and you have to replace the axle as well so both match. I think I read that somewhere but I`m not 100 percent sure. Jim
I have never read or heard of this. If it's true, it ain't good.
I don't know why a manufacturer would be making replacement parts different from the originals.
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ECVJeeps
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Post by ECVJeeps »

Problem solved!
It seems that a bearing retainer plate is required on each side of the rear axle. The part that is mis-represented in the M38 Manual as a shim and should be labeled as a bearing retainer plate.
The plate was missing from both sides of the rear axle assembly. Once I added these parts and adjusted the shims for the rear axle assembly everything fell right into place.

Thanks for everything guys, just had to look a bit closer to figure things out.
1952 M38CDN (in progress)
1942 GPW 51859(in waiting)
M100 CDN #0548(in progress)
M100 CDN #0281
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