M1123 12K Halfshafts...a few questions:

[JO-0321]

Howdy...

Finally got around to tearing into my halfshaft project on this new rig. A couple of the boots were rotten and torn so my plan was to just remove, relube, and replace the boots. Ran into an issue with one of the halfshafts. Pardon my terminology errors, I'm sure I'll mess some of it up...but I'll do the best I can. The "spider assembly" as it's referred to in the TM had thrown one of the bearings on it. I haven't cleaned it up much yet to fully inspect, but so far it looks good other than the bearing having come apart.

So...here are the questions:

1) I can't find this piece (spider assembly) for order anywhere...I assume this halfshaft will just need to be replaced, yeah?

2) If I need to replace one...would it be wise to just replace them all?

3) If it's recommended that I replace one or all of them, where's the best price for these things? I'd like to buy OEM...does anyone know if Midwest Military Equipment's half shafts are OEM? Otherwise, best price I'm finding is on GenuineHumveeParts.com

4) Lastly...if I go down the route of replacement, can anyone confirm these NSN's just so I know I'm ordering the right parts:

• 1x - 12460369-6 (LH Front)
• 1x - 12460369-5 (RH Front)
• 2x - 12460369-4 (Rear)

I need to figure this out quick....I'm blocking the driveway into the garage so my wife has to park outside...and she's not happy about it.

Thanks a million!

Funny side note: My nephew has been working on these things in the Army for the past 21 years. When I called and asked him for advice on replacing the halfshaft boots, he just laughed and me and said they replace the whole thing when the boots go bad. Later on, he looked up prices for halfshafts, called me back and said he's probably thrown a million dollars worth of those things away over the years that were perfectly good other than the boots! Ha!

 

[Coug]

#1 I can't answer. I did a search for both the part number and the kit it is part of, and neither shows up anywhere as available.

#2 there should be no reason to replace them all if the rest are in good condition other than the boots. A set of boots is a lot cheaper than the shafts are.

#3 Genuinehumveeparts is AM General's website. It's the most reliable place to purchase OEM parts.
Other than that MacMotors, HPG and Kascar are the go-to sites.

#4
According to the manual, LH Front is NSN 2520014214588

None of those match the part number you have listed.

Remember that there are actually several versions of the 12k shafts. The ones for the solid brake disc are different than the ones for the vented disc.
The one you have shows 12460369 is for the solid or wilwood discs according to HPG

12460369-6 / 01-474-4012 / 2520-01-474-4012 - HALFSHAFT, FRONT (LH 12.1 GVW) [GKN] | Hummer Parts Guy (HPG)

www.hummerpartsguy.com

In the parts manual use "NNN" for the UOC (Usable On Code) in the righthand column to match up different parts with the model they are specific to. "NNN" is for M1123.

Doing web searches for the NSN is also better than just the part number, as too many of them are a number then a "-3" or "-6" and all it takes is someone entering the wrong number, or your search engine using fuzzy logic, to come up with wrong parts.

 

[JO-0321]

#2 there should be no reason to replace them all if the rest are in good condition other than the boots. A set of boots is a lot cheaper than the shafts are.

Okay…I noticed that the grease in the inner joint on the two halfshafts that I removed (rear) was slightlymilk chocolaty colored as opposed to the outer joints that looked darker. Is this an indication of anything bad?

I wouldn’t be surprised if these are the original halfshafts…they look well used. Insides seem to be okay though. There is this heat stain on the other shaft that made me wonder…see photo…any reason for concern there?

 

[Coug]

I'm no expert on halfshafts, but as long as there was grease in the boot, and there isn't anything that looks damaged/excessively worn, I'd put new grease, reassemble with new boots, and run them til they fail. The difference in cost between boots and shafts is more than worth the risk, and even if it fails in a few thousand miles, that's still decent.
Even if I was ordering new shafts, I'd still rebuild the old ones to keep around as emergency spares, as you never know when you might need one right away.

 

[JO-0321]

I'm no expert on halfshafts, but as long as there was grease in the boot, and there isn't anything that looks damaged/excessively worn, I'd put new grease, reassemble with new boots, and run them til they fail. The difference in cost between boots and shafts is more than worth the risk, and even if it fails in a few thousand miles, that's still decent.
Even if I was ordering new shafts, I'd still rebuild the old ones to keep around as emergency spares, as you never know when you might need one right away.

Excellent...thank you. And thank you for the catch on the halfshaft NSN's. I have the 12.1 vented rotor.

Quick follow up question: When you re-build, how well do you clean out the old grease? The first one I took off, I did NOT remove the outer joint from the shaft as I don't think the joint would come apart even if I did remove from the shaft. I soaked the outer joint in solvent for a long time to get the old grease out of there...not sure if that's necessary...maybe better to just get out what I can and then put new stuff in on top of what's left of the old stuff.

 

[Coug]

I'm not 100% clear on how far you disassembled, but as long as it's out of the cup portion and you can get to it all, then it should be far enough.
After soaking with the solvent and getting what you can with solvent and plastic brush, some compressed air and brake clean to get as much of the rest as you can. Once you've soaked it in solvent, any remaining grease is contaminated, and will in turn contaminate the new grease.

If not soaking in solvent or using brake clean, as long as there's no contamination or metal shavings, you should be okay with getting what you can out and then adding new. Not necessarily the best method, but a lot easier and cleaner.

 

[JO-0321]

I'm not 100% clear on how far you disassembled, but as long as it's out of the cup portion and you can get to it all, then it should be far enough.
After soaking with the solvent and getting what you can with solvent and plastic brush, some compressed air and brake clean to get as much of the rest as you can. Once you've soaked it in solvent, any remaining grease is contaminated, and will in turn contaminate the new grease.

The upper joint is fully disassembled and out of the cup portion. I don't believe the lower joint (wheel side) comes out of the cup...even if removed from the shaft...at least as far as I can tell...but I have no idea really. I'm kinda just going off the photos in the TM. I've struggled to find much information on disassembly of that lower joint on this halfshaft.

 

[Mogman]

That "heat stain" is where the parts are hardened