Project Money Pit

Page 18


Driveshaft/Hub Stud Issues

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It's been nearly a year since my last update to Project Money Pit.   I have done a few upgrades since then, In January I posted an article on beefing up the stock Toyota axle housing after discovering I had bent mine.  At the same time I also installed bigger knuckle studs for the steering arms.  So far the new housing has been working well, no signs of bending.  The bigger knuckle studs also solved the problem of the original studs stretching over time, eventually coming loose and snapping.  I have been checking the steering arm studs before every trip and they have maintained their torque for the past few months.  When I was swapping out the knuckles I also installed new studs and dowels in the wheel hubs. I was still finding loose hub bolts from time to time and I figured some fresh factory studs would alleviate this problem; it didn't, more on this later.

A gearing upgrade was also installed in January.  I received an 8:1 gearset for the transfer case and beefed up the transfer case mounting system to handle the anticipated loads the new gearing would generate. After a couple months with the 8:1's I can say I am very happy with their performance.  My old 117:1 crawl ratio was adequate for most stuff but on really technical climbs I still wanted slower wheel speed for finer control. The 8:1's really delivered, providing a 156:1 crawl ratio which feels just right with the 37's.  For the easy stuff on the trail I find myself using 2nd gear which is 83:1.  I'll post more on these when I get some more time in with them but so far no complaints.

I did manage to find a new weak point, the driveshaft flanges on the pinion end of the shafts.  After a while mine tend to get ground up pretty good, eventually shedding enough material that the u-joint cap retaining clips are no longer held in place. The u-joint cap then pops out and that pretty much ends the day.  Even if I had a spare u-joint I cannot retain the caps anymore.  This same thing happens to the ears on the driveshaft end and when that happens I have to get that end of the shaft replaced.

My solution was to weld a 3/8" washer over the retaining clip, basically providing more material to have to grind through before the u-joint retaining clips are knocked loose. In theory, once the new welds are ground down to the point where the washer is knocked loose I can re-weld another washer in there.  We shall see if this pans out. To attach the washers I laid down a few tack welds at a low power level and then let the end cool, repeating this until the washer was completely encircled with weld material. When I was done I flushed out the old grease. 

Next up where some hub related upgrades.  Best I could figure the stock hub studs were stretching due to my usage beyond their original design intent, I mean, could you even buy 37" tires back in 1980?  For stronger studs I turned to Front Range Off-Road Fabrication and their new upgraded stud kit complete with 12 8740 chromoly studs and lock nuts (made by ARP).  From what I gathered on the internet the theoretical yield/tensile strength of 160,000/190,000 psi  is a nice upgrade over a class 10.9's 150,000/136,000 psi. I honestly think the stock studs are closer to a grade 5 since they are not very hard to drill so their numbers would be even lower.

Along with the upgraded studs I had Hendrix Motorsports machine the locking hub and wheel hub to accept 4 more dowel pins.  This product is not yet on their website so you'll have to call if you have any questions.  It ran $100 for the set (that includes adding the 4 dowel holes to 2 locking hubs and 2 wheel hubs as well as new dowels). The first thing I noticed when sliding the new locking hub over the 6 dowel pins is it is a nice and tight fit, no slop like a standard hub.

While I was in there I also installed some new front wheel bearings.  The best price I found was from Marlin's 4x4 & Off-Road, for $45 dollars a side you got two bearings and all the required seals.  They also have a great price on stock knuckle studs and cone washers.

Speaking of cone washers, I hate getting those things out,  so much so that I actually purchased a tool that was supposed to eliminate the hassle of pulling the locking hub.  The tool bolts on where in place of the locking hub dial and allows you to pull the hub and cone washers by  turning a jack screw which bottoms out on the axle shaft. Try as I might I could not get the cone washers to come off and still had to resort to the old hammer/screwdriver/cuss method of removal (and yes, I did remember to remove the retaining clip on the axle). I tried the tool on the other side with the same results so I am not sure it was worth the $20 since I still had to pry the cone washer open and work them off one at a time.

Once I got the locking hub off of the drivers side I discovered one broken dowel pin.  It was an odd break, deep inside the wheel hub so the pin actually still seemed functional.

On the passenger side I found one broken stud.  I am fairly certain this broke when I was checking the stud torque values at the Hammers, I felt it give when the torque wrench hit 20 ft-lbs. It was most likely cracked before I checked the torque, either way a 4 month lifespan wasn't very impressive.  Time will tell if the upgraded studs and extra dowel pins are the answer.

The last upgrade is something I should have done a long time ago, beadlocks.  I actually haven't had much of a problem running my Baja Claws at 4 psi until I started to run water in my tires.  The water definitely lubricates the bead surface making it much easier to push the tire off the bead.  I like the extra stability  and increase in traction the water provides so I knew I'd have to do something.  The other big reason I wanted beadlocks is for the extra strength the ring provides.  As you can see above, after a year of hard use my rims had some pretty serious rock related carnage on them. I am sure a few minutes with a hammer and these rims would be fine but some of the other advantages of a beadlock wheels eventually convinced me to make the leap, one of them being the ability to pull a tire off the rim on the trail or in camp.  Since I don't carry a spare I would like the ability to apply a patch internally in the tire if plugs fail to seal it up.

I chose the 18 bolt MRW beadlock rims (formally MRT) in a 15 x 8", 2" backspacing.  They used to be one of the cheaper ones but with the recent rise in steel prices they were roughly $30 more a piece than they used to be.  What's that saying, you gotta pay to play?  I also went with the rockcrusher ring option.  For an additional $25 per rim they provide a thicker and wider ring that will keep rocks from getting stuck inside the rim and the ring also provides protection for the valve stem.

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