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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Thu Jan 21, 2021 9:45 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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DanHoug wrote: |
the picture of the bearing balls under the orange seal is not good. abnormal amout of gray, which is metal. you've made the right call to take this back apart. just a guess but either the wrong bearing dimension was used or there was installation damage. |
Thanks. I’d be curious to see one of these bearings taken apart new from the factory and see what it looks like! I don’t have any experience with grease color and the amount of metal that might be in it, but many signs were pointing at the bearings being the culprit (because I installed them incorrectly with the outside grease). Hopefully your comment is just another indicator that this was indeed the case!
MarkWard wrote: |
I’m surprised to see that much scoring on the ID of the one inner race. Next assembly freeze the hub before pressing. The scoring appears to be from assembly and disassembly, not from seizing.
Also, the side by side is interesting. You are making a sandwich when you assemble these. The tolerance is machined in and all parts must be the correct dimensions. |
Yeah I was surprised the first time I saw the surfaces. Here’s a photo of the hubs when I first removed them. I have no clue if that scoring came from me removing the bearings or from someone else doing the job before we owned the van.
Seeing the feedback from people here, I think I’m going to remove the driver side too (I bought 2 more bearing replacements and 4 seals) and I’ll throw both hubs in the freezer between our tub of waffle cone vanilla ice cream and home smoked salmon fillets!
11BC2 wrote: |
Did the bearings come pre-greased?
I ask, because judging by the pictures, there's way too much grease on those bearings.
Also, the grease you added may not be compatible with the the grease that bearings come with. |
The bearings are pre-packed indeed. I made the mistake of adding waaaaay too much grease outside of these bearings following the installation details from someone else’s blog (I’ll have to let them know). My best guess is that the unnecessary grease created pressure against the orange plastic bearing cage and friction. But you are correct, there is too much grease on the outside of these bearings! I have no clue if it looks like there’s too much inside, but I have to assume they came with the correct amount from the factory since these are sealed. _________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17123 Location: Retired South Florida
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Posted: Thu Jan 21, 2021 9:49 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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I was referring to the scoring on the inner surface of the bearing race. Especially since you thought it pressed apart pretty easily. You don't want to change the diameter of the stub shaft, but maybe some 320 might clean off some of the high spots so that when it goes back together it doesn't score the inner races. _________________ ☮️ |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Thu Jan 21, 2021 10:17 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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MarkWard wrote: |
I was referring to the scoring on the inner surface of the bearing race. Especially since you thought it pressed apart pretty easily. You don't want to change the diameter of the stub shaft, but maybe some 320 might clean off some of the high spots so that when it goes back together it doesn't score the inner races. |
Oh I see. There’s no scoring on the inner race itself that I can feel by hand. I wondered about sanding some of that surface down, but seeing how one side already had a small reduction in diameter, I decided against anything more than steel wool. I used some high temp sleeve retainer compound when reassembling though, hoping it’d help keep things together. _________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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Zeitgeist 13 Samba Member
Joined: March 05, 2009 Posts: 12115 Location: Port Manteau
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Posted: Thu Jan 21, 2021 10:40 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Syncros, like most FWD/AWD VAG vehicles come with sealed front bearings, so there's no need to add extra grease, other than a light assembly coat to aid the hub stub into the inner race bore. Speaking of, that hub stub looks kinda scored up, but it's hard to tell. As mentioned, try cleaning them up with a light grit emery cloth. You should also clean the outer seal surface on the hubs. _________________ Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Thu Jan 21, 2021 10:42 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Zeitgeist 13 wrote: |
Syncros, like most FWD/AWD VAG vehicles come with sealed front bearings, so there's no need to add extra grease, other than a light assembly coat to aid the hub stub into the inner race bore. Speaking of, that hub stub looks kinda scored up, but it's hard to tell. As mentioned, try cleaning them up with a light grit emery cloth. You should also clean the outer seal surface on the hubs. |
Yeah, I'm gonna do a better job this time around I think (and definitely not add grease). I also hadn't realized where the bearing and outer CV seals would sit until I reassembled the parts. I'm going to clean these contact surfaces too. _________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17123 Location: Retired South Florida
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Posted: Thu Jan 21, 2021 10:51 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Talking about the race in this picture.
It looks distressed to me. _________________ ☮️ |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Thu Jan 21, 2021 11:53 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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MarkWard wrote: |
It looks distressed to me. |
I see! Here are photos of the exact same inner race cleaned up with a little bit of brake cleaner for reference. This is the same bearing just pictured from both sides. There might be some very minor scoring on the surface though I haven't tried very hard to scrape off the surface.
_________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17123 Location: Retired South Florida
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Posted: Thu Jan 21, 2021 12:17 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Well, that's certainly looks fresher. Carry on. _________________ ☮️ |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9605 Location: Western WA
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Posted: Thu Jan 21, 2021 12:30 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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I think those scored surfaces main function is to center and support the races.
Sanding it with 320 etc would not reduce the diameter if you don't sand the scratches off.
All you want to do is remove any high spots - so they done cause additional galling and more scratches.
Be sure to "wash down" and float all the carborundum grit (or steel woll) off.
Discoloration of the grease is alarming.
Hard to tell in pics, but grey means steel, right?
And orange color changing, perhaps due to temperature?
Something is strange here and prob good you took it apart.
Not being there, it's difficult to offer ideas.
Can you put that grey grease hanging on a very soft thread, and check if a magnet 'pulls' it? _________________
'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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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Thu Jan 21, 2021 3:43 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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I wasn’t able to learn anything from a magnet and the grease... it’s just too messy for me to tell if there’s enough metal in the grease that it’s magnetic.
I also used 600 grit (didn’t have 320 grit) on the hub. Used a sheet of sand paper around the shaft and spun it. I couldn’t feel any raised surface catching, but it looks cleaner. Here’s how the other side looks by the way (the original one that had the loose axle nut). The lines are interesting. It seems that there is definitely damage from the loose axle nut, hopefully not enough that a new bearing will have issues.
Not sure what these marks mean... maybe that the bearing spun a fraction of a mm, breaking loose, before it starting pulling upward?
In any case, I wonder how much it would be to have this part machined... seems like a good contender for a machine shop out there.
Since I removed this side, we’re able to see the difference from side to side. Here’s the passenger side again, the one that was overpacked with grease and running 20° hotter than the other side:
Here’s the driver side, which had less grease packed into it and was running cooler:
To me the differences are obvious. The problematic one had its red grease turn dark gray and the grease inside the bearing seemed like some metallic fudge. The other side had its red grease still red and clean looking ball bearings. Here’s another photo with the ball bearings only comparing sides. As a reminder, there’s only about 140 miles on these and the right side wheel hub was running at least 20° hotter when testing.
_________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9605 Location: Western WA
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Posted: Thu Jan 21, 2021 4:34 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Sodo wrote: |
Can you put that grey grease hanging on a very soft thread, and check if a magnet 'pulls' it? |
A little blob of the grey grease - hanging on a thread?
Under Gravity a magnet may pull on it - if its full of steel.
Also you can mix it with gasoline in a glass jar and the steel will fall out onto the bottom.
Do you still have any grey grease or is it all wiped away?
It would be kinda good to know if thats steel, pretty darn important for solving this problem before reassembly. _________________
'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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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Thu Jan 21, 2021 5:49 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Sodo wrote: |
Also you can mix it with gasoline in a glass jar and the steel will fall out onto the bottom.
Do you still have any grey grease or is it all wiped away?
It would be kinda good to know if thats steel, pretty darn important for solving this problem before reassembly. |
I did the gasoline thing.
Grease from inside the bearing: saturated with metal!
Grease from outside the bearing: some metal but less.
I’m wondering if the grease I added pressed the orange seal of the bearing inward. When things spun and heated up, grease from inside the bearing could’ve seeped out, contaminating the outside red grease. Just a theory. _________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Thu Jan 21, 2021 8:49 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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New update: I just finished pressing the bearings back in. I only used the thinnest film of grease to coat the outer seals. I installed the steering knuckle on the passenger side (the problematic one), without the axles and without brakes. In this exact scenario, when I tried spinning the wheel by hand, the wheel would stop within 2 seconds. Now with the new bearing, the wheel stops spinning at 6 seconds.
I installed the CV joint (without the axle) and torqued the nut, the wheel stops spinning just after 2 seconds (used to be just 1 second).
None of this is very scientific but it was clear to me that the wheel was much easier to spin without all that grease than it was when I overpacked the bearings.
I’ll keep installing everything and I’ll try to take that same drive tonight or tomorrow, without using the brakes and measuring hub temps. I’ll measure rotor temps too. _________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Fri Jan 22, 2021 2:55 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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I put everything back together and went for another test ride doing the same loop as before, stopping in the same spots (without using the brakes) to measure temperatures. Conditions were similar though about 5º cooler (43º to 44º instead of 47º to 49º the first time around).
I measured temperatures on the rotors, which is a bit finicky with an IR gun but the rotors never got over 70º. I only had to brake briefly once on the second test in order not to turn right without stopping at a red light as a car was coming!
Here's a graph of my measurements.
The dotted lines represent the first test, before replacing both front wheel bearings.
The solid line represents this latest test, after replacing wheel bearings.
The blue lines represent the passenger side (right side).
The green lines represent the driver side (left side).
It would seem that replacing the bearings fixed the hot wheel hub issue. Our right side wheel hub used to run 20º hotter than the left side when I performed this short, low stress test. I imagine the difference from side to side was much more significant after extended highway driving (which I didn't get to measure). Though it was a few degrees cooler outside, both sides seem to run cooler and both sides are the same temperatures.
Another thing I noticed was that the cage of the outer front CV was cooler on the passenger side by 15º to 20º (from about 115º at highway speeds down to 99º), however the driver side was running about 10º warmer than before (from about 115º at highway speeds up to 124º). I'll have to keep an eye on this, though I do intend on replacing those outer CV's eventually.
I'll keep an eye out on things but I'm thinking (hoping) this one is solved. Bottom line is:
Don't pack the sides of your syncro front wheel bearing with grease!!!
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In case this image of the graph disappears, here's the temperature the data:
0.4 mi, max speed 10mph
Right side before wheel bearing swap (RB): 66º
Right side after wheel bearing swap (RA): 57º
Left side before wheel bearing swap (LB): 59º
Left side after wheel bearing swap (LA): 57º
1.4 mi, max speed 35mph
RB: 90º
RA: 72º
LB: 70º
LA: 72º
2.8 mi, max speed 35mph
RB: 100º
RA: 75º
LB: 80º
LA: 78º
5.6 mi, max speed 60mph
RB: 126º
RA: 92º
LB: 100º
LA: 91º
7.8 mi, max speed 60mph
RB: 123º
RA: 95º
LB: 100º
LA: 94º
10.3 mi, max speed 40mph
RB: 119º
RA: 85º
LB: 97º
LA: 95º _________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery
Last edited by T3TRIS on Fri Jan 22, 2021 10:27 am; edited 2 times in total |
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4Gears4Tires Samba Member
Joined: October 08, 2018 Posts: 3028 Location: MD
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Posted: Fri Jan 22, 2021 8:29 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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T3TRIS wrote: |
I'll keep an eye out on things but I'm thinking (hoping) this one is solved. Bottom line is:
Don't overpack your syncro front wheel bearing with grease!!! |
Or just don't touch it at all when installing. It's sealed. Leave it alone. _________________ '87 Syncro
Ferric Oxyhydroxide Superleggera Edition |
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jimf909 Samba Member
Joined: April 03, 2014 Posts: 7466 Location: WA/ID
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Posted: Fri Jan 22, 2021 10:08 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Nice work. I love science!
_________________ - Jim
Abscate wrote: |
Do not get killed, do not kill others.
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Current: 1990 Westy Camper - Bostig RG4, 2wd, manual trans w/Peloquin, NAHT high-top, 280 ah LFP battery, 160 watts solar, Flash Silver, seam rust, bondo, etc., etc.
Past: 1985 Westy Camper - 1.9 wbx, 2wd, manual trans, Merian Brown, (sold after 17 years to Northwesty who converted it to a Syncro). |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17123 Location: Retired South Florida
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Posted: Fri Jan 22, 2021 10:47 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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There's an old trick for removing VW pilot bearings. You pack the bore with grease and then using a spare input shaft, you force it into the grease and it walks the pilot bearing out.
In other words, you probably did develop some pressure with the added grease that wasn't playing well with the other parts. _________________ ☮️ |
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korkwood Samba Member
Joined: February 08, 2005 Posts: 63 Location: Los Angeles
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Posted: Fri Jan 22, 2021 12:44 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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It sure is a very long discussion. Just wanted to chime in
I am sure heat was caused by improperly installed bearings.
Nothing to do with extra grease, if there was too much of it would easly escape thru the seals. Nothing to do with torque as more torque doesn't do anything to bearings except squeeze hardened inner race more.
I have seen "professional mechanics" installing bearings wrong way
These bearings have to installed carefully and in certain order. |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Fri Jan 22, 2021 1:05 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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4Gears4Tires wrote: |
Or just don't touch it at all when installing. It's sealed. Leave it alone. |
You're right, I re-worded it.
jimf909 wrote: |
Nice work. I love science! |
Thank you!
MarkWard wrote: |
There's an old trick for removing VW pilot bearings. You pack the bore with grease and then using a spare input shaft, you force it into the grease and it walks the pilot bearing out.
In other words, you probably did develop some pressure with the added grease that wasn't playing well with the other parts. |
Ha, I love these types of clever tricks! Heck I tried to do the inner race wheel bearing removal heat trick when replacing those bearings.
Link
In my version, I hung some rope from the garage joists with a carabiner, connected 3 pieces of metal wire to the studs, sandwiched them with a wheel spacer and lug nuts, connected the assembly to the hanging wire, wound it up and let it spin back while putting a propane torch to it. Didn't work... at all.
Fortunately there was enough of a lip on these particular bearings that they were easy to remove with a standard puller.
korkwood wrote: |
It sure is a very long discussion. Just wanted to chime in
I am sure heat was caused by improperly installed bearings.
Nothing to do with extra grease, if there was too much of it would easly escape thru the seals. Nothing to do with torque as more torque doesn't do anything to bearings except squeeze hardened inner race more.
I have seen "professional mechanics" installing bearings wrong way
These bearings have to installed carefully and in certain order. |
It is indeed a long discussion but I'm thinking the following quote explains it best.
T3TRIS wrote: |
I’m thinking the excessive grease on the outside of the bearing was getting pushed around when pressing the wheel hub into place. I suspect the grease pushed the outer seal outward ever so slightly as the hub kept moving inward. The wheel hub eventually met the bearing seal, which is pretty stiff and I believe has an internal metal ring. Then it became a fight between the metal wheel hub pushing onto the bearing seal and the plastic protection on the side of the bearing itself resisting. As more pressure was applied with the press, I bet the outer seal and its internal metal ring won the strength fight and was able to keep the grease inside the assembly. Since the grease itself can’t compress and probably wouldn’t seep out of the seal while the hub could still move inward, the outer plastic cage of the bearing itself was the next weak link and got pushed against the bearing balls.
At least that’s what I’ve been thinking since I first remembered I put grease in there, especially when it was pointed out that the grease was unnecessary. |
Here are the few elements that make it tough for me to think it was something else:
Before replacement, the right side bearing was consistently 20º hotter than left side during short 10mi drive with no breaking. I know I overpacked the right side significantly compared to the left. Barely any grease spewed out when pressing the hub into place.
After the replacement, both bearings run slightly cooler and they both run about the same temperature. The only thing that changed was not adding grease to the outside of the bearings.
You're right, these bearings need to be installed properly and over-torquing shouldn't create heat/pressure as you'd probably strip the threads before you compressed that hardened metal. But that grease can't compress either and almost none of it made it out of the seal, it had to go somewhere, or create pressure on the bearing cage.
Little PSA by the way, be careful pulling and folding cotter pins toward your face with long needle nose pliers, almost lost a tooth!
_________________ Guillaume, Jennifer & T3TRIS
87 2-knob Syncro
- 94 Subaru EJ22, 225/70-R16 CLK 16x7 ET37
- Transaxle rebuild, Mexico paint job, Front end rebuild, 320Ah LiFePO4 Battery |
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korkwood Samba Member
Joined: February 08, 2005 Posts: 63 Location: Los Angeles
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Posted: Fri Jan 22, 2021 1:36 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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I always put grease next to bearing and never ever had the "hot hubs".
Too much grease escapes thru seals but keeps dirt out of bearings
Just replaced bearing on one side, not because it was worn but 2 studs spun after taking my Syncro for tire work.
Dirt roads really mess up Vanagons...but also lead to better life |
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