BOMB Your Rear Hubs! (Long-even for me)

[Extreme1]

Here it is, for all you guys who can't leave well enough alone (or want to improve on a stock thing).



A few issues ago, one of the editors suggested tilting the truck to drain and refill the rear hubs when changing the diff lube. I recently did a rear brake job (which turned into 3 new bearings-but that's another story) and after disassembly realized that:

1. Mag Hytech covers rule! Due to their level checking and fill methods (and the o-ring cover seal, the main reason I bought it) you can make sure lube will get into the hubs.
   
2. You have to fill the diff nearly to the axle to get lube into the hubs.
   
3. Once it is in the hubs, you need to remove the axle to only get most of it out (I couldn't get much out when I tried tilting and now realize it was just in the tubes).
   
4. To get ALL the fluid out of the hubs, you must remove them.
   
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   So, I got to thinking. Then I called Dana and spoke with an engineer.
   
   
   
   I theororized:
   
   The hubs are WAY over designed for the weight they carry. (Theory confirmed).
   
   
   
   Drilling and tapping a 1/8" pipe plug into the hub won't hurt it. (It won't).
   
   
   
   Draining the lube at the hubs is a good idea. (It is).
   
   
   
   My solution was to drill into the hub about 1 5/8" from the surface the axle mounts to and tap the hole for a 1/8" pipe plug. This is just outboard of the area where the wheels pilot (on the outside) and just inboard of the radiused area where the outer bearing race stops (on the inside).
   
   
   
   I went with 1/8" plugs because I had 2 shiney new allen head plugs that size just lying around. In hindsight, smaller would make filling really hard! You need to make sure the holes are tapped deep enough so the plugs are slightly below the surface so they don't interfere with wheel installation.
   
   
   
   So, to drain the hubs, remove the plugs and rotate the hub so the hole is down. To refill, rotate so hole is up. Any excess on refill will run into the diff through the axle tubes. (unless you are pouring at a good rate, then it will run on the ground )
   
   
   
   When I asked about this marvelous (to me) idea, the engineer said: Yeah, well Navistar gun drills one of the axle mounting holes and does the same thing that way. Then they patented it! That is when I started to feel a little stupid, but not much. (Why didn't I think of that?) That is also an option but refilling would be more of a challenge unless you did the tilt method. Also, my method can be done with the stock cover and you won't have to pack grease into the wheel bearings!
   
   
   
   I also asked about grease in the wheel bearings. Dana can't recommend anything other than what the OEM (Dodge) states as service procedure. (And I know NOBODY on THIS site would EVER do anything other than what DODGE recommends. ) I was told that I wouldn't be the first to refill the hubs with just oil (without grease) and that I wouldn't have any problems.
   
   
   
   So, for those of you needing more detailed instructions:
   
   1. Remove the hubs from the truck per the FSM instructions.
      
   2. Remove (and discard) the seal and remove the inner bearing.
      
   3. Locate the area to drill and tap the hole. Double check that you are inboard of the outer bearing race stop radius and outboard of the wheel pilot area. Also, try to avoid the casting parting line and center the hole between a couple of studs. (Just engineering theory to minimize stress risers. )
      
   4. Drill and tap the hole so the 1/8" pipe plugs are just below the surface when tightened into place.
      
   5. Clean the hubs out. Make sure you get ALL the chips out!!!
      
   6. Clean and inspect the bearings. Now is a good time to replace any bad ones. NOTE: the bearings are the same from the first generation and are also the same for 60, 70 and 80 series rear ends. (According to NAPA. )
      
   7. Install the inner bearing (oiled with the same stuff you are going to fill the diff with) and a new seal. Use sealant on the outer edge of the seal so it can't leak between the hub and the seal.
      
   8. Reassemble per FSM instructions. (Including the bearing set up part. )
      
   9. Fill hubs with diff lube before installing wheels and install the plugs.
      
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      Go forth and modify!
      
      
      
      The disclaimer:
      
      As usuall, if you do this to your truck and something fails or you do it wrong, don't blame me. You are responsible for your truck, I am responsible for mine. If you don't think you can do this modification, I would agree with you. Don't do it. You know you better than I do.

 

[Archive]

Great Idea...........

Extreme 1, I would venture to guess you are a real stickler about keeping all of your fluid levels fresh, clean, and topped off. I'm not going to perform this modification untill I'm in the process of seeing to something else. (i. e. brake job) Thanks for the post.

 

[NVR FNSH]

pics?



Brian

 

[Extreme1]

Not really a stickler but...

Thanks, TopFuel.



I had both bearings spin on one side. When I dumped the oil out of one of the hubs there were lots of chips in it from the nut being rubbed by the outer bearing. At that point I was happy that it stayed in the hub. Then, after looking at the design, I figured that that oil had to have been in there since before I owned it until I added the Mag Hytech (80,000+ miles). Unless you pull the hub, no way to get it out. I wonder how long it was like that. Other side was fine except for the outer bearing being worn.



I wouldn't have done it unless I had it apart already to fix a seal or loose bearings (problem with mine). Glad I did though, it will make the next diff fluid change complete.



Pics? Not much to show except for a little plug in the hub. If I get a chance... (No digital camera and the Mrs just took all our vacation film in to get developed).