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  View original topic: Question re Drive Axle Shaft
DAIZEE Sat Apr 12, 2014 9:30 am

Is it a common occurrence for the drive shaft to break? Last year my left one sheared off the bolts and this year the same thing happened to the right one.

What causes it and is there any preventative measure to be taken?

Terry Kay Sat Apr 12, 2014 10:03 am

Bolts don't just shear off on their own--for no reason at all, especially at the axle at the end of the CV joints--

Somebody didn't tighten them down--they worked loose & snapped, fell out--whatever.

If you were seriously off roading--yea--they might snap, but not trundling down the road.

Be sure to locktite the mounting bolts if this seems to be a problem.

syncrodoka Sat Apr 12, 2014 10:38 am

That isn't a common problem.
Proper torque with a clean surface between the CV and the flanges has never failed me and I do stupid things. :wink:

Wildthings Sat Apr 12, 2014 11:28 am

You need sufficient torque so that the bolts only see high but fairly constant tension forces. If the torque is too low then the bolts will see pulsating tension forces and also pulsating shear forces which lead to fatigue and eventual failure.

DAIZEE Sat Apr 12, 2014 11:31 am

thanks all. Yes we are going to use Locktite on them. I suspect loose so this will be another thing to keep an eye on whenever up on hoist.

Terry Kay Sat Apr 12, 2014 11:37 am

Like I mentioned.

If the mounting hardware wasn't tightened down, they worked loose, & broke.

If she feels that there is an issue with this, a drop or two of locktite on the threads sure wouldn't hurt.

Return the vehicle to the Guy that installed them---look for some warranty on the shoddy workmanship.

morymob Sun Apr 13, 2014 5:28 am

Only time any of mine broke was during new install using the 'bright plated' bolts, doing final tq & bolt broke at end of threaded section. Removed shaft & dug into my stash of used bolts & replaced ALL, won't use these again, china ?, el cheepo other brand? my-2cts.

DAIZEE Sun Apr 13, 2014 6:35 am

hopefully my new bolts are coming from a reliable German resource. I am aware of cheap or white metal, etc.... As the second time this happened was different side to the first time and I think it was original bolts so as I said I will have to keep an eye of all their tightness henceforth and to use locktite.

Terry Kay Sun Apr 13, 2014 6:50 am

The CV mounting bolts are hardened---and shouldn't have been soft, stretchable bolts.
Somebody somewhere just didn't put enough armstrong on them, and they worked loose.

It would most certainly been a wise & prudent move to go over to the other axle and check them out--
If one side came loose & failed, who's to say the same thing wouldn't happen to the other assuming the same lame backyard handyman installed both axles at the same time?

This I think was somebodies poor decision not checking out the other axle prior to it blowing off too--that's all.

Randy in Maine Sun Apr 13, 2014 6:57 am

Are you also using the correct Schorr washers and the "torque spreader bars" as well as the hardness 12.9 bolts?

DAIZEE Sun Apr 13, 2014 10:35 am

Have added locking washers to left side when it was repaired as well as the loctite. Will ditto it on right side AND check left side again as well. Only qualified, certified mechanic do my van now (since 2011) and 2 Vanagon mechanics.

Again thanks for all your input.



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