I just discovered a problem with my front hubs, the right side being so severe, it locked up the outer wheel bearing. After pulling the hub and cleaning out the grease, I found 3 bulges in the inner wall of the hub that are directly associated with the bolt holes for the locking hub. Here's a few photos of the right side. I found one bulge on the left hub that is not a problem, but is still a concern. If anyone has experienced the same issue, please post. I can't really figure out what caused this problem other than over-torquing the bolts for the hub locks and/or silicone sealant used to seal the hub lock getting into the bolt holes and forcing the metal to expand... which seems to me to be unlikely. But you never know... <img src="/forums/images/graemlins/zombie.gif" alt="" />

Here you can see 2 bulges and a third that was worn flat, along with a rough patch on the surface of the race right below the flat. <img src="/forums/images/graemlins/scared.gif" alt="" />

After much contemplation and examination of the hub shown above, the only thing I can find that would have caused the inner wall to bulge is the compacting of the black sealant used to seal the locking hub. The bolt holes have an accumulation of the sealant in the bottom of the threads, which is where the bulging occurs. I never thought about that being a problem. And it's probably worsened by the multiple times I've pulled the manual locks for various projects. I resealed them every time, not realizing the compound was gathering inside of the holes. Factor in the heat from braking and it might just be the perfect storm that caused the problem. I can't see the torque from running with the hubs locked being the problem, as I have very little time driving that way. And I suspect that any looseness in the bolts would produce an ovaling of the holes, where the bulges would require the tips of the bolts to be pulled inward, towards the bearing. That makes no sense to me because all of the forces applied by the drive system are rotational. That said, you should be cautious when using a sealing compound like RTV or a canned compound (I used the latter) so it does not get inside the bolt holes of the hub. Enough material building up might cause problems like I've encountered.

I have new hubs and parts to install. I will likely use a small amount of RTV this time, only applying it to the o-ring area of the locking hub so the excess can't get pulled into the holes during assembly. I'll be sure to post a follow-up to this after it's all back together and I've got some miles on the odometer.

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Hi, I have seen this type of damage before though not in a wheel hub. Being that the holes are blind holes, if there is an excessive amount of sealant in the hole when the bolt or screw is tightened there is not enough space and you basically(spelling?) created a hydraulic ram. Something has to give and since the sealant can not travel back up the threads it deforms the metal. I actually broke part of a two piece valve cover because of this. The tech that worked on the engine before me used too much and I did not check the holes before I installed it. $200 part broken that the shop had to eat and my <img src="/forums/images/graemlins/butwiggle.gif" alt="" /> chewed out.

Thanks for the response. It really helps to confirm the source of the problem. This fix required 2 new hubs, 2 full sets of wheel bearings and 2 sets of new wheel studs. The end cost was close to $300, primarily because I ordered the hubs through Amazon Prime to get them in time for installation on Friday. That's all done and I can focus on finishing up wiring my electric fans to finish my extensive overhaul... <img src="/forums/images/graemlins/baby.gif" alt="" /> That noted, I was very sparing with the RTV Black (tube-type, not the canned). I think everything will be OK now. Lesson learned! <img src="/forums/images/graemlins/shiner.gif" alt="" />

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I actually never use sealant on my manual hubs when I put them on, and have never had a problem even after driving through mudholes and standing water. I figured there would be all sorts of nastiness in my hubs, but nada. I don't even use threadlocker. <img src="/forums/images/graemlins/lol.gif" alt="" />