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mackaymanx
Samba Member
Joined: October 12, 2006
Posts: 479
Location: Australia
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 Posted: Mon Jan 09, 2017 3:58 pm Post subject: Re: Syncro front hub repair - anyone try knurling? |
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| IdahoDoug wrote: |
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.
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After knurling you machine it back to the size required. So bring it up bigger than you need with the knurl then take it back to size. |
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nstuart
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Joined: April 01, 2008
Posts: 11
Location: Vancouver BC
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| Posted: Tue Sep 08, 2020 12:32 pm Post subject: Re: Syncro front hub repair - anyone try knurling? |
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Following Sodo's story, I am just starting to investigate a similar situation with my 1986 syncro -- after investigating some rubbing noise that I think I narrowed to the front passenger wheel, I noticed that my hub nut was not very tight, causing quite a bit of play in the wheel (both side to side and top to bottom), and loosening of my steering rack (twice!) over many miles through the Rockies and BC's Costal mountains!
I tightened the hub nut down and the play was substantially reduced. Now I need to investigate further to see if there has been any damage to the bearing and, as I see from your post, the hub itself.
I am not sure who the culprit is for the loose nut: Might have been me, as I recently changed the front CV boots on both sides, after which I might not have tightened the nut to 258 lbs, or is it possible that the mechanic missed this after I had an alignment done (after upgrading to 16" Mercedes rims)?, or could the new rims have caused the vibration?
Anyway, but both times, it was the play in the steering that alerted me to the situation (perhaps I had become used to the constant wheel rubbing noise).
But unlike Sodo, I did not hear any 'creaking' or other noises apart from the rubbing. However, I did notice a strange 'lurching' of the van as I rounded an S turn going a bit too fast, while breaking.
Any information would be appreciated as I continue my investigations.
Stuart
'86 Syncro |
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MarkWard
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Joined: February 09, 2005
Posts: 17155
Location: Retired South Florida
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| Posted: Tue Sep 08, 2020 1:37 pm Post subject: Re: Syncro front hub repair - anyone try knurling? |
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I don’t see how taking rims on and off could affect outer cv joint torque. Even if the wheels wobbled. The outer cv nut is a crimp nut and should be replaced. When the cv comes loose, the inner bearing races walk away from each other. No idea how much they can take. It’s the front suspension, so I’d pull it apart and at minimum new bearing and seals. Inspect the hub. Hopefully it is not damaged. I’ve seen replica hubs for sale. Plan on a new outer cv nut and the book calls for the cv splines to be loctited into the hub. I don’t do that. Makes it difficult to field service.
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9618
Location: Western WA
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| Posted: Thu Sep 17, 2020 1:04 pm Post subject: Re: Syncro front hub repair - anyone try knurling? |
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| mackaymanx wrote: |
After knurling you machine it back to the size required. So bring it up bigger than you need with the knurl then take it back to size. |
Agreed, the knurling/machining re-centers the bearing.
258 ft-lbs pre-load holds it all in place.
The knurling is irrelevant once it is torqued.
However if it ever loosens again, the knurling won't resist much and it will start creaking more readily.
I bet knurling is a good solution if a replacement hub cannot be found. So don't discard a hub.
_________________
'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 |
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jlrftype7
Samba Member
Joined: July 24, 2018
Posts: 3582
Location: Chicago
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| Posted: Fri Sep 18, 2020 7:36 am Post subject: Re: Syncro front hub repair - anyone try knurling? |
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| Sodo wrote: |
| mackaymanx wrote: |
After knurling you machine it back to the size required. So bring it up bigger than you need with the knurl then take it back to size. |
Agreed, the knurling/machining re-centers the bearing.
258 ft-lbs pre-load holds it all in place.
The knurling is irrelevant once it is torqued.
However if it ever loosens again, the knurling won't resist much and it will start creaking more readily.
I bet knurling is a good solution if a replacement hub cannot be found. So don't discard a hub. |
Don't Knurl it, get it metalized. I spent a few months in the mid 80's working for a place that did that in St.Louis. They spray molten metal onto the part, and machine it once it cools back to whatever spec you needed.
They can match the metal, or add something a bit different with a different wear factor. You can't tell the part was ever worn or bad when these people are done with it. I worked mainly on the huge printing press rollers that they were rebuilding as a stock job. But they did lots of small parts as well. Very cool technology .
Price out the hub to get a quote from one of these places, it would interesting to see if the price for the work was decent enough , not too expensive.
Looks like St. Louis place closed and was bought out. But anyway, here's the general idea of how these places work their magic.
https://www.mgf-services.com/on-site-cylinder-repair
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto |
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9618
Location: Western WA
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| Posted: Fri Sep 18, 2020 7:40 am Post subject: Re: Syncro front hub repair - anyone try knurling? |
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| jlrftype7 wrote: |
Don't Knurl it, get it metalized
.......
it would interesting to see if the price for the work was decent enough , not too expensive. |
I predict $400 for metalizing
$200 knurling.
But knurling is possible to get it for free if you know an old codger with a lathe..
Only problem is you have to spend the time listening to their stories.
(or reading their long posts) 
_________________
'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 |
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jlrftype7
Samba Member
Joined: July 24, 2018
Posts: 3582
Location: Chicago
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| Posted: Fri Sep 18, 2020 8:57 am Post subject: Re: Syncro front hub repair - anyone try knurling? |
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| Sodo wrote: |
| jlrftype7 wrote: |
Don't Knurl it, get it metalized
.......
it would interesting to see if the price for the work was decent enough , not too expensive. |
I predict $400 for metalizing
$200 knurling.
But knurling is possible to get it for free if you know an old codger with a lathe..
Only problem is you have to spend the time listening to their stories.
(or reading their long posts) |
BUT, and this is important, with knurling you aren't getting the same level of metal fit that the part or design originally called for. ANd it's a poor treatment for something that's oval or out of round a bit from wear already on the part.
Call around for a quote, it will interesting to see how pricey it really is.
A batch of hubs would probably lower the cost per item since the set-up time is reduced once the run is started.
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto |
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9618
Location: Western WA
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| Posted: Fri Sep 18, 2020 9:46 am Post subject: Re: Syncro front hub repair - anyone try knurling? |
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| jlrftype7 wrote: |
| BUT, and this is important, with knurling you aren't getting the same level of metal fit that the part or design originally called for. ANd it's a poor treatment for something that's oval or out of round a bit from wear already on the part. |
There’s a limit to knurling’s ability to raise the surface.
It can only raise “so high”. I don’t know this “number” or its details.
The caliper and the behavior of the hub will tell you. Whether the knurling can raise the surface depends how long the van was driven under the insufficient axle nut torque.
And after knurling, you CANNOT put weight on wheels before theres 258 ft-lbs torque on the axle. Without the 258 ft-lbs, the knurling could be crushed. And nobody knows this specific vulnerability except you. Some garden-variety Syncro mechanic could “assume” that it can sit on the shop floor not rolling around.
Thinking about THAT..... is why you should torque the axle nut as much as possible, like 100 ft-lbs or more BEFORE putting any weight-on-wheels to do the 258 ft-lbs. Better to put all 258 on before ANY weight-on-wheels. This might produce the best-centered bearings assembly. Hmmmm....Wonder if the Bentley addresses this.
Knurling would be a stopgap solution for sure.
Agreed a batch of 10 restorable hubs to be sprayed & re-machined might be efficient. With a batch of 10 to measure the machinist can predict a better target diameter and tolerance. But who’s got 10 hubs?
_________________
'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 |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17155
Location: Retired South Florida
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| Posted: Fri Sep 18, 2020 11:15 am Post subject: Re: Syncro front hub repair - anyone try knurling? |
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| Quote: |
| But who’s got 10 hubs? |
Dylan? But he is saving those. 
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Sodo
Samba Member
Joined: July 06, 2007
Posts: 9618
Location: Western WA
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| Posted: Mon Jun 20, 2022 6:28 pm Post subject: Re: Syncro front hub repair - anyone try knurling? |
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check out this tool for removing the front hub inner race.
Link
Skip ahead to minute 1:40
Not too difficult to rig one up if you don't wanna buy/wait for it.
Maybe put a brake hub on it for the mass to keep it spinning.
Or even a wheel?
I wonder if a propane torch could do it, or if it requires the concentrated heat of that oxy/acet cutting head.
I'd be concerned that the wide, cooler propane flame heats the hub too, then the hub will expand at (almost) the same rate as the race and not let it go.
_________________
'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 |
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hans j
Samba Member
Joined: May 06, 2006
Posts: 2715
Location: Salt Lake City UT
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| Posted: Mon Jun 20, 2022 10:01 pm Post subject: Re: Syncro front hub repair - anyone try knurling? |
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I do it that way all the time. Oxy/Actyl torch and sit the hub on a couple sockets so it rotates freely, then spin and heat. Old inner race is off in less than a minute.
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1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181 |
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