Couple of broken driveshaft questions

2005 DC/LB 4x4 lurker here. Stock motor, 32" E-range tires, full length welded sliders, full set of Budbuilt 3/16" steel belly armor, mid-travel suspension with ~3" lift, much higher spring rates, no front swaybar, usually loaded heavy with overland gear for 2ppl + 2 dogs for weeklong trips with no pavement

I had a crummy situation this past week on a week-long wheeling trip in Anza-Borrego State Park (CA). Pushing thru what I thought was only a moderately technical rock garden, the back wheels dug out between rocks and brought the rear driveshaft down on a central rock. Looks like I dragged and dented the rear shaft tube, which then torqued off completely under load.

Made a video to explain what happened to my non-technical family (probably too basic for this crowd after the first minute): https://youtu.be/shxbcfjCk8c

No damage underneath except the shaft. I was able to back out and self-rescue in front wheel drive. The only replacement I could get quickly (the Wednesday before Thanksgiving weekend) was O'Reilly grade, no zerk fittings on the U-joints (only on the slip joint), and U-joint straps with little 8mm bolts on the center joint keeper straps instead of a solid yoke. The price was not good but it did save a long planned vacation so I guess I can live with it

Question 1: this is the only truck I've had, and I hadn't come across the removable U-joint straps before. There was no torque spec in the documentation or anywhere the parts store guys could find. I searched some - apparently these used to be common in domestic RWDs - and gave them 30 ft-lbs and a tiny dab of red loctite and didn't feel any bolt stretch as I did. How sturdy are these things? Is this a timebomb waiting to come apart?

Question 2: I'm thinking of trying to rebuild the stock shaft with a heavier rear tube; is it as simple as take it to a driveline shop and tell them that? I'm not impressed by the wall thickness on the busted OE shaft. FWIW I pulled the whole 2-piece shaft and replaced all the joints about 2 years ago; lucky I did as it was hard to remove then and pretty easy on the trail this time. Maybe put the repaired original back, and keep this replacement as a spare since it can break in half to stow much better? Or is re-welding this broken tube asking for trouble?

Thanks

 

I’d take it to a driveshaft shop and have them rebuilt it. I have a local FleetPride that does it here. They’ll turn off the ends and weld in a new tube - even thicker wall if you want.

 

Damn. I've dented and replaced mine a few times, but never had it die like that.

Yeah, you can take it and see if they'll retube it, but a new shaft from Toyota is ~$700. Keep that in mind versus whatever price they give you.

 

Are you talking about the carrier bearing? Aka Center Support Bearing?
Just about all the Torque Specs can be found on the forum here
https://www.tacomaworld.com/threads/the-torque-spec-guide.318116/

 

No, I'm asking about this highly non-stock arrangement on the replacement shaft. The central U-joint, aft of the center support bearing, on the stock Toyota shaft has solid yokes on both sides of the joint and needs a bearing press to disassemble. On the replacement shaft, the center-rear yoke is solid but the center-front yoke has two separate brackets (U-joint straps) holding the U-joint needle bearing cups in place. These are held down with four smallish bolts with 8mm heads. You can see them just behind the carrier bearing in the first attached photo. I just don't know how suspicious to be of those little bolts.

 

Ohhh…..ok.
Yeah. I’m not sure on that.
I call them u-joint caps.
I’m quite sure that’s not the correct name.

And the few times I messed with them, I didn’t use a torque wrench.
I didn’t use a Torque Wrench on anything until I joined TacomaWorld.

 

Spicer calls them bearing retainer caps and bolts.
Here is a link to some charts.
https://spicerparts.com/resources/lube-torque-specs

M8x1.0 runs about 28 ft/lb.
But that doesn’t mean much with after market stuff.
But it’s a reference anyways.

 

As for questions #2.
I can’t help there. I’ve seen some guys on here, run a 1 piece rear shaft from Tom Woods.
But I’m not sure that’s what you are looking for?

 

Driveshafts don't have to be thick to carry torque - a circular hollow tube is extremely efficient at that. Making a thicker wall tubing might help with dent resistance somewhat but it would twist just the same after a big enough dent.

If you want to prevent that from happening upgrade to bigger tires or blame your spotter!