Axle hubs not fitting correctly.

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Axle hubs not fitting correctly.

Postby ECVJeeps » Thu Mar 08, 2012 5:07 am

I was getting ready to paint and install my rear axle on my wife’s M38CDN and found when I installed the drums that they were sitting too far out on the axle and leaving a gap between the edge of the drum and the backing plate.
The hubs are on as far as they can go, and the axles are making contact with each other on the ends, (with shims installed there is no contact).
I have removed the hub and checked how far the axles sit in the housing without the race and I can feel the two axle ends touching so they are in as far as they can go.

Image
Image

It was mentioned that I may have the wrong hubs on the axels; I thought that there would not be that much of a difference from one jeep to another and that you could take one hub from one jeep and install it on another.
This jeep is being assembled from spare parts to make one complete jeep; this keeps another one on the road and uses up some of my spare parts. I have already given away enough parts to build another jeep.
When this jeep is assembled all my “extra” parts and pieces will be going also, time to clean the shop of excess parts.
Does anyone have any idea of why my hubs are sitting so far out on the axels? I was just wondering is there that much of a difference between M38 hubs.

What am I missing, what did I do wrong?

Pat
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Re: Axle hubs not fitting correctly.

Postby Ben Dover » Thu Mar 08, 2012 6:02 am

The Hub/Axle taper on all M-Series Jeeps as well as Universal Jeeps is identical, they share the same part number. Are your Drums drilled with the 3 Countersunk Holes to attach them to the matching holes on the Hu bs? Another detail is that the Keys may be inserted incorrecyky. Always installthe Keys after the Hubs are in place on the Axles. Care must be taken to insert the keys in a manner that matches the taper of the axle shaft, you can tell when they are correctly installed when they can be inserted all the way with just finger pressure. Failure to install them incorrectly and drawing them in with the Axle Nut will distort and crack the Hub where it enters the Seal.
Did you install the shims and retainer rings for the shims in the correct order and use a dial indicator to give each shaft 0.001"-0.006" end play? This must be done for both sides. Also noted are the plugs installed on top of the Axle Housing Tubes, remove them and install the Relief Valves, failure to do so will blow your seals.
Did you consult the TM when assembling the rear axle assy.?
NOTE:
I have NOS Relief Valves.
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Re: Axle hubs not fitting correctly.

Postby ECVJeeps » Thu Mar 08, 2012 6:13 am

Hi Joel
The hubs have the three holes for the screws that anchor the drums onto the hubs; the lug nuts are both left for one side and right for the other. I am using brass screws to anchor the drums onto the hubs as I find that the brass won't rust like the steel.
The hubs were installed without the key, the key was added after.
Both axels were shimmed, so I took one axel out to see what was in the way and without the bearing race the axel can be felt hitting the end of the other axel.
The edge of the bearing is just showing past the end of the axel tube. I have more pictures and can send or post them tonight.
The plugs are correct and the grease nipple is only installed to prevent the vents from getting damaged when I sandblasted the housing. The correct vents will be installed after the axel assembly is installed and painted.
I tried to download the manual from the M site however there was an error every time I tried to download a copy. I have loaned my copy to someone and it seems to have grown wings!

Thanks, I will re-check everything tonight when I get home, this darn job keeps getting in the way of my garage time.

Pat
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Re: Axle hubs not fitting correctly.

Postby Ben Dover » Thu Mar 08, 2012 7:09 am

You may not have enough shims which allow the axles to contact the block, are the shims installed on the housong correctly? They are installed prior to installing the retainer ring. My thoughts are that if all the parts are correct that the shims could be the problem.
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Re: Axle hubs not fitting correctly.

Postby ECVJeeps » Sat Mar 10, 2012 1:56 pm

Joel you were as close as possible to being correct.
The rear axle assembly was missing the bearing retainer plates, the part that is labeled as shims in the manual.
With the bearing retainers in place and the axle re-shimmed everything fell into place. It would appear that the
manual has one part mis-labeled as a shim when it is in fact a bearing cone retainer. Without this part the backing
plate sits too far inboard and makes the drum appear to be sitting out too far.

Problem solved, thanks guys.
My wife's rear end is now as good as new! :wink:

Pat
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Re: Axle hubs not fitting correctly.

Postby Ben Dover » Sat Mar 10, 2012 3:24 pm

Thank you.
It had to be the problem. Which manual has the error, I am curious, the ORD9 SNL G-758 dated September 1956 as well as the Willys factory Parts List are OK.
When you add grease to the two rear wheel bearings, pump it in very slow untill the pin on top of the check valve just starts to lift and then stop. Pump it too fast and you will chance blowing the seals at the backing plate and greasing your brake shoes. Do not grease this location more often than every 12,000 miles.
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Re: Axle hubs not fitting correctly.

Postby ECVJeeps » Sat Mar 10, 2012 4:26 pm

The TM 9-1804B shows what appears to be two shims and labeled as shims part "E", # 7374982
when in fact it is one shim and one bearing retainer.
Just a bit confusing until you look real close and see that the two parts are different.

Curious about greasing the bearings, There is only a check valve and a pipe plug at the rear bearings, should there be a grease
fitting someplace there. I don't have a copy of the TM 9-840.

Cheers.
Pat
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Re: Axle hubs not fitting correctly.

Postby Ben Dover » Sat Mar 10, 2012 4:34 pm

The Army had an urgent MWO back in the mid 50's to temporarly remove the alemite grease fittings and install Pipe Plugs in order to prevent drivers and mechanics from having a too frequent urge to lubricate the rear wheelbearings. There were too many incidences of outer rear axle seal problems and greasy brake shoes. The fittings are reinstalled only at scheduled maintanence time.
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Re: Axle hubs not fitting correctly.

Postby ECVJeeps » Sat Mar 10, 2012 4:46 pm

So it would be ok to add the grease fittings again? They go in the bottom and the vents at the top I suspect.

Thanks again for the knowledge.

Pat
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Re: Axle hubs not fitting correctly.

Postby Ben Dover » Sat Mar 10, 2012 7:39 pm

Vents are at the top, and you say you have them?
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