Stripped Syncro front axle nut

[MarkWard]

[4Gears4Tires]

With a deep enough socket I can see the valve spring trick working nicely, cool idea. A helper pulling/levering the CV from the other side sounds like a pretty solid idea as well. Pulling may not be enough pressure, not sure what to lever against except maybe the cv boot, slamming/jerking the cv shaft in coordination with the impact bursts maybe.
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'87 Syncro
Ferric Oxyhydroxide Superleggera Edition

[Abscate]

Grab the nut with Channelocks and unscrew it a big Crescent.

Once it picks up a few threads that are unreached, it will zip off
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.ssS!

[blyhigh]

OK. It's off. Used a dremel with a tungsten carbide cutting tip.

[img]https://www.thesamba.com/vw/gallery/pix/2089627.jpg[/img]

[img]https://www.thesamba.com/vw/gallery/pix/2089626.jpg[/img]

[img]https://www.thesamba.com/vw/gallery/pix/2089622.jpg[/img]

[img]https://www.thesamba.com/vw/gallery/pix/2089624.jpg[/img]

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[img]https://www.thesamba.com/vw/gallery/pix/2089621.jpg[/img]



Looks like the the new nut did some damage to the threads on the new axle. I'm now afraid to force my old axle nut on to this. What to do? Is there a way to rethread the axle shaft?

[djkeev]

Not sure why your pictures didn't show, but here they are.

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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[blyhigh]

Thanks. Not sure why they didn't show either.

[Wildthings]

[MarkWard]

That’s why I asked about the joint originally. I would not accept it. A spacer is for when you are in BF Egypt. Contact the supplier and tell them what happened.

I have a tool called a thread file. It will straighten threads that are keeping something from starting. Yours are damaged where the critical torque happens. It’s obvious you didn’t cross thread it and there is now way to really mechanically over torque it. It’s defective. Time for them to honor a warranty.
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[?Waldo?]

^^^I agree.^^^

[Sodo]

Spacer could work.
The question is.... can you get 258 ft-lbs of torque on that axle?
And will it remain tight (at 258 ft-lbs) as you drive your 500 mile trip?
I'd be checking on it periodically.
But if it strips when you are re-tightening (on the road) you have to flatbad.

That axle, as you know is low quality and obviously "strippable".

I think you should get that POS axle off your Syncro, before you ruin your (NLA) hub.
Note you will have to buy a new bearing if you disassemble the hub.
Syncro front wheel bearings can only be "installed", they are destroyed in disassembly.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[blyhigh]

It's a VW Axle Assembly GKN Loebro 251407271J. Is there something better than this? What if I got two more Syncro font axle washers and added them then reused the old nut or got a new one with similar specs? That was the first axle I ever did myself and the thought of tearing it all apart again is enough to make a grown man cry.

Btw, has anyone used the GW Nylock nut on their front axle?

[MarkWard]

It’s your van, you can do what you want. You’ve gotten advice to replace the joint and advice to shim it. These parts are mass produced and there was a problem with the hardness on this joint. Possibly luck of the draw.

The point your missing is the hub which is NLA and wheel bearing depend on that outer cv to hold them together. If it loosens or worse fails, it will first wipe out the bearing and then the hub which you can’t buy new at the moment.

I’ve been doing this for many years, this stuff happens. When it’s a simple part like a window winder, it’s easy to replace. A Syncro outer cv, not so much. I recently rebuilt my Syncro gear box and reinstalled it. A couple months later I got an email from the supplier to please send back one of the internal parts that might prematurely fail. So, an outer cv is gravy by comparison. Best of luck with your decision.
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[dkoesyncro]

This happened to me, once the nut was off the threads were done! I took it to a fabricator I know who welded it up on a carousal and then off to the machinist to cut new threads. The machinist was very impressed with the welders work that these two now often work together, and I salvaged/saved my high dollar part.

I swapped out to a better nut and took the advice of a local syncro guru and reassembled with red rtv.

[4Gears4Tires]

Ouch. I'd throw a thicker washer / 2nd washer / large nut in there for the mean time while you go on your trip and then talk to the supplier to replace it. As long as you are only grabbing fresh threads, it should be ok. I have done this in a pinch. Obviously, it's not an ideal long term solution.

If it happens a second time, haha, well, you're SOL, time to wait. I wouldn't be surprised if it happens a second time either.

Nice job splitting the nut btw.
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'87 Syncro
Ferric Oxyhydroxide Superleggera Edition

[candyman]

My concern with adding a spacer or washer is that torqueing that nut will cause the same issue with stripping the threads. If the shaft threads are faulty then this will happen again. I would bite the bullet and replace the shaft with another one. Like others have warned, you do not want to destroy that hub.

Out of curiosity, how many miles do syncro wheel bearings last? And do adding larger tires (19.5-20” axle to fender lip) put greater strain on them? Asking for a friend

[4Gears4Tires]

I absolutely agree, if the metal is defective, you run the risk of stripping the threads again. But what is the cost of that risk? Stripping more threads of an already marked to be junk part and then cutting another nut off? That doesn't seem like a very costly risk. If it holds, it holds. I doubt very much it'll just decide to spontaneously strip out in 300 miles. A little locktite for piece of mind, sure why not.

Bigger tires and especially bigger wheels where the off set moves outwards puts a much bigger strain on wheel bearings. On the lady's Ford Explorer with 33" tires, front wheel bearings last about 2-3 years. Luckily, the bearing assembly bolts in with 3 bolts! Takes 20 minutes to change.
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'87 Syncro
Ferric Oxyhydroxide Superleggera Edition

[Syncro Jael]

Worst case scenario is to purchase a completely new front half shaft for around $275. Pull out your old one and you will have it fixed correctly. I do reuse the original nut with Loctite. Again the correct torque is crucial in keeping the wheel bearing intact. Do not use an impact gun to install. Torque it by hand with the correct settings.

If not spacers to keep the nut on good threads should work. I like Loctite and would always use it in these situations.

Cheers,
Ron
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1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[Sodo]

These days we all have seen examples where a quality brand is no longer quality. Valuable companies get sold at high value by vultures who will plunder the brand. Buyer reduces manufacturing costs, but customers are unaware. Reputable resellers are caught in this scam, purchasing the junk parts at premium prices. The vultures plunder the brand's reputation to generates a profit exceeding the purchase price. They got their money back, and more. Done deal.

Perhaps they can sell the injured brand to another, lower-level vulture, who spends some $$ on advertising, propping up the brand enough to do it yet again.

Or perhaps it was just a single GKN manufacturing error (one bad part).

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The main concern is: your specific axle may not have strong enough threads to support the required torque (258 ft-lbs).

The evidence suggests the threads are weak.

Consider this procedure? I bet you already thought of it.....but just laying it out here.

1) Get an arrangement of spacers that will set the nut to engage the clean threads as discussed. Spacers should be very 'square' and flat etc. A stack is ultimately more compressible than "one washer" - a stack is not a good thing to maintain critical torque, but may work. Wildthings suggestion of using a single 'large nut' as a single thick washer, is a good method. The fewer interfaces, the better.

2) Torque it to 258 ft-lbs. Oil on the threads. You wrote that your torque wrench "ends at 250 ft-lbs". I'd use it to 225, even 250, then continue with the manual method of "your body weight" divided by 258 times lever arm (in feet). If you happened to weigh 129 lbs then the lever arm is "2 feet". Pretty easy calculation, but ya gotta try to get the center of pressure on the lever arm to be "correct". Finding a person weighing around 129 lbs, I bet you could get a pretty accurate torque setting. Whereas there's less accuracy using a 12 inch lever arm if you weighed 258 lbs. Shorter arm has more difficulty in accuracy of the 12-inch center-of-pressure. But it CAN be done with some thought.

3) Then loosen it and unscrew the nut, inspect. Do the threads appear to be strong? How did the nut unscrew?, Do threads still spin smoothly?
If yes, come up again to 258 ft-lbs. Did it come up firmly, similar to the first time? Maybe check a 3rd time? If that gives you confidence, move onto #4.

4) OK assuming it all seems good, go on your trip, but re-check the torque soon, and as often as you can. But don't forget. And if it doesn't come up to 258, and starts to strip, then you KNOW it does not have proper compression holding the bearing races together. Which is a flat-beddable offense !

I would not use loctite in this application. A thread locker will mess with your ability to re-assess the torque 'by feel' during your trip. Loctite is best used in vibrational environments where two parts that are fastened together can 'shift' and thus unscrew the threads. A bolted connection where you cannot prevent the part movement, but you CAN impede the bolt from rotating.

There is no movement in this fine-thread, concentric 258 ft-lb preloaded connection. It's not the right application for Loctite. Assessing/guessing whether the threads are failing, is more important for this situation. If it's not loosening (after a couple checks) it won't ever loosen thus Loctite would be a hindrance and no benefit.

Anyway, by the conclusion of #3 you can make your decision on #4 and "the trip".
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[MarkWard]

The second time you replace the outer CV, it's bound to go quicker.
The sooner you contact the supplier the better.
It will be on your mind the entire trip
When you get back, you still need to replace it.

The time, spent on this thread, the new joint could already be installed. Best of luck.
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[Wildthings]

258ft*lbs is only 3% over 250ft*lbs, so 250ft*lbs is plenty close enough. If you must have 258ft*lbs then just turn the wrench a tiny bit more once you reach 250 and be done with it. We aren't building a rocket to go to the moon here.