Project Money Pit

Page 17


Warn Hub Problems

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I have done quite a bit of crawling with the new suspension.  So far everything is working like I wanted it to.  I have found a few weak spots, check out the 4 link article for more updates.

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Project MP got a new exhaust system!  The old one was a hodge podge of original and aftermarket components that was barely hanging on.  I won't mention the shop that did the old setup, needless to say I won't be going back.  The new system was installed by Mighty Muffler (602-944-5210) to my specs.  I wanted a smaller catalytic converter, tucked as high as possible with flanges so I could easily remove sections for trail repairs.  2" exhaust tubing was used (same as stock) and the muffler ended up being a glass pack to conserve space.  With the smaller catalytic converter in place I can now design some skid plates to protect the exhaust from behind the front tire to the t-case.  This is the one area I get hung up on if I misjudge the size of an obstacle.

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I had the rear axles out in the top picture to weld up a small crack in my differential housing.   Here's what the splines look like after a year and a half of hard wheeling.  I was actually pretty surprised there was no twist evident in the splines.  There is some slight deformation showing, looks like the splines are kind of squished for lack of a better technical term.  For now these went back in, well the passenger side did.  The drivers side had a bad bearing, really bad actually.  It wobbled pretty nicely when spun.  I ended up installing my spare axle on the drivers side.  New bearings are on the to do list and Within the next year or so I'll most likely upgrade to the All-Pro cro-moly rear axles at the same time.  

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Once I got the back all put back together I turned my attention to the front. I am running Warn premium hubs up front and had been having problems keeping the mounting nuts tight.  It had gotten to the point where they were loose after every trip.  Eventually I sheared a few studs off of one side.  On closer examination I sheared 3 studs (one fell out on hub removal) and one of the dowel pins.  The dowel pin holes were egged out in the hubs so I exchanged the hubs for some new ones.  I managed to fish the broken studs out of my wheel hub with a screw extractor, the broken dowel was a little more challenging.  I ended up having to put the wheel hub in the mill at work so I could drill a hole in the middle of the dowel using a carbide end mill (not something the average person can do at home on a drill press).  Once the hole was drilled I used another screw extractor to pull the dowel remnants out.

Sheared stud and dowel extract via a carbide end mill and screw extractor

I actually skipped a few steps, before I even thought about repairing my wheel hub and exchanging the locking hubs under warranty I went to install my spares.  The spare parts came from a truck that had run 33" tires.  I was surprised to find sheared dowels on each side of that axle as well as broken studs. This didn't seem right.  If the dowel was doing it job of locating the locking hub, the studs shouldn't be seeing a shear load and shouldn't work loose. So I determined I needed to swap out my locking hubs for a new set, replace the dowels and studs and everything would be fine.

To my amazement the dowel pins flopped around in the dowel holes on the new locking hubs.  Using some gage pins and a micrometer I determined the dowel holes on the Warn hubs measured .290", the dowel pin is .2756".  This tells me the dowel serves no purpose.  With that much slop it can neither accurately locate the locking hub nor help retain it's orientation, the two reasons a dowel should be used.  So without the dowel taking the shear forces, the studs will see the forces if the nuts work loose.  As I have discovered,  the lock washers used on the Warn hubs do not provide enough clamping force to keep the hub body from rocking which leads to sheared studs and dowels.

Stock hubs have one critical difference when compared to the Warn hubs, cone washers.  By using cone washers on the studs, the stock hubs basically turn all 6 studs into dowels, allowing no movement of the hub as long as the nut is tight (and remember the cone washers squeeze the stud when you tighten the nut helping to ensure a good tight grip).  So what does Warn say about this flaw (and they must have said something otherwise I wouldn't have wrote all of this)?

I was told the dowel holes on the Warn hubs are used only for alignment.  Their official spec for the holes is .290 +/-.003 which is way to big to be a slip fit for a 7mm dowel, hence worthless as an alignment feature.  I suggested they tighten up that tolerance to make their product better.  Ignoring my advice I was asked what size tire I was running and then told my tires were to big.  Hold on a minute.  When I look at the way Warn advertises their premium hubs I am a little confused.  From the Warn website:

"A no-comprehensive hub designed for the hardcore off-roader who will accept nothing less than the industry standard in performance. "

Apparently the industry standard is lower than the OEM standards. The stock hubs hold up just fine with even bigger tires without working their way loose after every trail ride. I'd also like to know their definition of hardcore.  33" tires are not considered hardcore, yet they are apparently enough to also cause the same problems as witnessed by the condition of my spare parts axle.  So as you may have guessed I am going to run some stock locking hubs.  I feel the cone washers used to secure the stock locking hubs are critical if you are going to run anything bigger than a stock tire.  I would also be wary of buying another Warn product due to the deceptive way they advertise. Makes you wonder what the fine print in their winch manual says, or their full floater axle kits?

Anyway, I have a set of brand new Warn hubs for sale, great for hardcore mall crawling.

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