Syncro front hub repair - anyone try knurling?

[Pcforno]

Sodo- if it helps, my rear hub castle nut was completely loose when I chased down a noise in it. It was recently replaced by a well-known and admired vendor here. It ruined the housing as well, but fortunately burley makes new ones for the rear. I know it dosent help your situation but I can empathize. The devil is in the details - it further reinforces to me the value of doing work myself- no one to blame except yourself when things aren't done right

[Sodo]

[Sodo]

What's that "D6 locking compound in a band 25/32" wide"
that Bentley pg 40.18 specifies for the axle splines? Red Loctite? Blue? Green? Is it Bearing mount? And 60 mins hardening before driving - what about "60 mins hardening" before putting weight on wheels?

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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

[IdahoDoug]

When I did my Syncro front axles, someone knowledgable said it was not needed. Sure enough, mine did not have it. So, I think it's just to prevent creaking vs being needed for the mechanical bond.

Doug
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Sodo]

I dunno about that....thinking about my axle wobbling around loose in some ole' hub, maybe walking the nut loose, ruining the no-longer-available hub. Who told you it didn't need locking compound? Maybe was the guy who did my axle? Sorry I'm kinda sensitive on this issue. I think I'm gonna glue this one up.

This seems strange, Bentley expects motion on the bearing outer circumference.
Bentley pg 40.23: (wheel bearing) "coat outer circumference with moly paste to prevent clicking noises while driving".
_________________


'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

[IdahoDoug]

yeah I did the grease coating against noise. went together and silent.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Pcforno]

Sodo- you should show a pic of you're ingenious LBJ press! That's guaranteed to help some folks...

[djkeev]

Smart giving up on the knurling idea.

Knurling is simply deforming metal in an organized pattern.
It does not increase diameter it only smushes the metal into low spots and high spots, you then pray that the high spots have enough beef to perform as hoped.

In minor applications, it works GREAT!!!

In applications with tons of weight and stress put upon them?
Not so good.
The wear surface is compromised and weakened. Failure will be quick and probably painful.

Replace, as you are doing, or weld and precision grind.

Probably throw in heat treat for hardness just for fun too.........

Dave
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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

[IdahoDoug]

Agree. I also would worry about precision from the perspective that some of the high spots will be higher than others. So the final resting position of the part might be at a slight angle - essentially needing an alignment, which perhaps would solve it.

Having said that, my buddy's new large camper trailer blew a wheel bearing in the middle of nowhere up in BC at a remote lake on its maiden voyage. Warranty sed ya gotta get it to an authorized repair center. Nearest? Back in the US - 300 miles and a tow he'd pay for of $1000. So he drove me up there with tools and a new bearing and I cut off the old one and staked the damaged axle. We spent the night in it, and took off for home the next day. About 8 months later, I asked him what happened and he'd forgotten all about it. Just dropped me off and drove home, then a full summer of trips with it. So, under certain conditions the strategy can be a good one.

Backstory was I checked the other bearings and added grease to their measly amounts but they were fine. This one either had none added at the factory, or so little it did not even matter.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Sodo]

[IdahoDoug]

I called Loctite about that years ago for the Quattro (has same bonding product wording in my Audi factory service manual) and they have an able product information staff. I described it and he recommended a product from their line, as well as one that was way more than needed. I do this often for products, and can't recall if it was this way at Loctite but some companies will let you ask for a call back by an actual trained engineer as well. So if you get someone you're not confident about, consider asking for a call back because its a rare vehicle, blah blah.

If you strike out, I'll see if the Audi manual is more specific. In fact, I'll check anyway 'cause I'm hanging out by the fire with my wife at home and the kiddos are out on the town somewhere.

I also had a bearing shell retainer question once and stopped at a store and got a 6 pack of Pepsi and then walked in the open back door of a big machine shop and asked for the foreman. He grabbed one of his top machinists and they discussed it in front of me and gave me their recommendation. I dropped the Pepsi on their break table, wished them a good weekend and left, knowing I'd gotten priceless advice.

Doug
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[IdahoDoug]

So, the lower powered versions of my Quattro call for a similar "Audi D6 locking compound 5mm wide" to bond the axle splines. The highest power version (mine) calls for the axle splines to be "unbonded".

I am under the impression that this use of bonding compound was simply to reduce creaking - an audible noise from the spline/hub interface under certain conditions. It's not for mechanical purposes beyond that - not to keep it from falling apart, generating fastener-loosening resonance, or causing spline wear. I'd guess it to be a historical cause of customer concerns they solved this way.

I know you are going to find out what it is and use it on yours, however! Heh - let us know what it turns out to be......
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[djkeev]

D6
It is apparently a thread locker based upon its use being called for in this T4 manual for the flywheel to crank bolts.....

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

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

[Syncrozilla]

Between my own cars and my customers I've probably had at least a hundred syncro front axles out and back in over the years. I've never used the locking compound and never had a problem not using it. It's not that I'm lazy and don't care or that I don't want to follow the directions either. If you've ever tried to take an axle out (like on a van that's never been apart before) it can be a real pain in the ass. Especially when you are at a campground in Baja working in the dirt. BTDT. It can take a LOT of hammering. I've never had a bearing/hub failure (probably because I carry a spare hub and bearing in my travel kit) but I have broke a few CVs off roading and I like to be able to take the nut off and slide the axle out easily.
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[Sodo]

I suppose the compound offers a higher level of surety that the customer doesn't hear funny noises on one hand, and on the other hand; noises that aren't nearly so funny. Like the creaking noises that I heard after it came loose (for whatever reason).

Syncrozilla thanks very much for adding your voice of experience. So with locking compound (and a spare axle on-hand) then a tool that will press a "glued" axle out "on the trail" is required? I think I could build a tool that's much smaller than the one Bentley shows. Your thoughts?

Here's the press tool for Syncro front axle shown in the Bentley Pg 40.18
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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

[IdahoDoug]

I know this will feed your fire, Sodo. So the tool shown is large, complex and heavy because it has to work on other vehicles. If you design it just for the Syncro so you can carry it, make the part that goes under the bolts a solid thick ring and then something for a normal a two arm or three arm puller to get a grip on. So in theory you could simply carry the ring and source a puller in nearly any town.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[vanonimous]

Sodo just a thought on welding a bead around the bearing race:
My machinist does this to bearing races pressed inside gearbox cases. When preping for rebuild he welds a bead inside the outer race. Lets it cool and it just falls out. It shrinks it, kinda fun to watch.
Maybe not the best idea to weld around the entire circumference of the inner bearing race, it would make it harder to remove.
_________________
If happiness is being a mechanic, owning a Vanagon is nirvana.

Lighting upgrades: https://www.thesamba.com/vw/forum/viewtopic.php?t=578291

[Sodo]

Everybody's heard about the welder who lights a cigarette while listening for the "tink". "Welding berries" perhaps hundreds of them; inside a trans gives me the willies.

I was pretty sure it couldn't refuse to pull off & I could still split it. It came off "hard". I am puzzled by the scratches though, and the rust-like stains too. I'm pretty sure the bearing was original.
_________________


'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

[MidwestDrifter]

When working on aircraft bearing surfaces (landing gear, engine parts, compressors etc) the go-to process for this kind of damage is hard chrome plating.

This can be applied using by immersion plating, but also through flame spraying. Flame spraying will usually be cheaper, and will allow thicker coating application.

The chrome can easily be built up to 25 thousandths (even thicker is possible). Once sufficient thickness is added, the part can be ground back to spec.

The chrome is very hard and wear resistant, providing a part that is usually stronger than the original.

Depending on the application the correct knurling pattern will increase the OD enough to restore the fit. For low-ish load situations (like the load bearing surface in a vehicle) the knurling will provide plenty of strength, and should not wallow if properly torqued. I would add some slip fit compound (loctite) to the knurled surface prior to assembly.
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[Sodo]

I think unless a guy had the ability to spray hard chrome, and grind it etc, the cost would be around GpoWestyoungMan's new repro hubs. I bet knurling would cost $100 (unless you had a crazy friend with a lathe and the knurling tool) . Maybe even THEN so!

Midwest thanks for your description and knowledge.

Doug I made a hub press tool per your prediction.
_________________


'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