Author |
Message |
T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
|
Posted: Tue Jan 19, 2021 12:18 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
mitch5 wrote: |
In that photo before you press the hub into the bearing, the entire outer bore seems to be filled with grease. Seeing a part pressed into a fixed volume with all that grease makes me wonder if its possible that when you pressed the hub in all the extra grease had no where to go and took out the bearing seals. I know that ball bearings are sensitive to lubrication and its possible that with a damaged seal the bearing could overheat.
Disclaimer: I havent gotten around to reassembling my bearings yet so i am not sure how much room there is in there for that grease.
I am impressed with how deep you have dug into this issue, Personally i would dissemble and put new bearings in without all that grease. Syncro hubs are exponentially more expensive than the bearings and if a shop did this work you would probably expect them to replace. Hopefully disassembly will reveal the "smoking gun" |
I too am really thinking that way. I mean... I did remove the steering knuckles late last night and almost just started taking the bearings out. I guess it meant I was pretty convinced already but I decided to wait for a little more feedback. I kick myself in the butt for not recording disc temperatures when I did my drive test. I didn’t smell any brake smell though.
Anyhow, I think I’ll go the bearing way. Having that grease seems like way too much and the side that I know was more packed is consistently warmer than the other side... _________________ 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 |
|
Back to top |
|
|
MarkWard Samba Member
Joined: February 09, 2005 Posts: 17009 Location: Retired South Florida
|
Posted: Tue Jan 19, 2021 7:36 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Non scientific study. Drove the syncro in this am. Ambient was 65 F. 15 min drive. City stop and go. Brake disc outer edge 200F. Lug nut 110F and the CV stub was 120F. I'm sure if I drove it harder and longer temps would increase.
My Ryobi temp gun does get thrown off by reflection. So, I shot the rusty lip of my disc. My lug nuts are new and shinny black, so the temps might be slightly reflective. CV stub is patina. _________________ ☮️ |
|
Back to top |
|
|
T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
|
Posted: Tue Jan 19, 2021 11:19 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
MarkWard wrote: |
Non scientific study. Drove the syncro in this am. Ambient was 65 F. 15 min drive. City stop and go. Brake disc outer edge 200F. Lug nut 110F and the CV stub was 120F. I'm sure if I drove it harder and longer temps would increase.
My Ryobi temp gun does get thrown off by reflection. So, I shot the rusty lip of my disc. My lug nuts are new and shinny black, so the temps might be slightly reflective. CV stub is patina. |
Your test: 15min city stop and go at 65° outside, 120° CV stub, 55° above ambient.
My test: 15/20min city and highway, no brakes at all, 49° outside, 126° hub (by CV stub), 77° above ambient and side overpacked with grease 20° warmer than the other side. Before the highway, my hubs got to 100° within 5-ish minutes of driving under 35mph with no brakes, 51° above ambient.
I drove my van in colder temperatures without using the brakes at all and the hubs got 77° hotter tan ambient temps, your drove your van in warmer temperature, using your brakes and your hubs got 55° hotter than ambient temps.
This is all done in non-controlled environments of course but I see a pretty good difference here. I still can’t believe I didn’t mesure my brakes! _________________ 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 |
|
Back to top |
|
|
MarkWard Samba Member
Joined: February 09, 2005 Posts: 17009 Location: Retired South Florida
|
Posted: Tue Jan 19, 2021 11:33 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Ok, at this point, replace one bearing, minus the grease and see if you can have a change side to side.
Again, most folks would have just ignored this. So your attention to detail is going to put you in the nut house. _________________ ☮️ |
|
Back to top |
|
|
T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
|
Posted: Tue Jan 19, 2021 12:00 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
MarkWard wrote: |
Ok, at this point, replace one bearing, minus the grease and see if you can have a change side to side.
Again, most folks would have just ignored this. So your attention to detail is going to put you in the nut house. |
Haha. I won’t debate that one!! Heck there are some good arguments to just put it back together and run with it, that’s for sure. In any case, thanks so much for contributing with your measurements.
I’ve put so many hours and so much effort on this front end rebuild though that I’d hate to see a potential mistake shorten the life of our bearings, CV’s, probably reduce brake power (if they run unnecessarily warmer) and potentially damage our NLA wheel hubs... as you say, I might fall in the nut house category though. I do wish it was a more obvious problem of course but at some point I’ll have to make a decision one way or another and live with it! _________________ 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 |
|
Back to top |
|
|
mitch5 Samba Member
Joined: October 17, 2019 Posts: 126 Location: phoenix
|
Posted: Tue Jan 19, 2021 12:01 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
MarkWard wrote: |
Ok, at this point, replace one bearing, minus the grease and see if you can have a change side to side.
Again, most folks would have just ignored this. So your attention to detail is going to put you in the nut house. |
Thats a smart idea, lets you keep one side to act as a control/baseline. Also not to put you further down into the rabbit hole but you can get thermocouples for alot of multimeters, my $25 harbor freight model has one. That would you give a way more accurate temperature.
Kudos for even noticing something too, its also possible that this is being over thought. There seems to be some good info on trailer hub temperatures, seems temps under 200f is normal. |
|
Back to top |
|
|
Sodo Samba Member
Joined: July 06, 2007 Posts: 9517 Location: Western WA
|
Posted: Tue Jan 19, 2021 2:15 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
MarkWard wrote: |
In theory, the grease you added could be creating friction. That's a stretch diagnosis. |
I have read often that too much grease will cause heat.
Its the 'stirring' of a viscous liquid..
Imagine if you had to spin that bearing with a bicycle crank.
The heat is your Wheaties® burning and at some point you would feel tired.
It takes "work" to stir the grease.
The result is heat in the same way that brakes change friction into heat.
Consider too that the excess internal pressure causes the seal lips to energize and bite down onto the seal lands, causing more friction (and perhaps a little more heat).
I doubt you've damaged anything yet.
I doubt the bearings are damaged (but they can be if you press them out)
I would scheme of a way to bleed the grease off. Can you remove the CV axle, and heat the housing with a torch?
Maybe heat-pressure without the 258 ft-lbs clamping will allow some grease to ooze out? _________________
'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
Last edited by Sodo on Tue Jan 19, 2021 2:48 pm; edited 2 times in total |
|
Back to top |
|
|
T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
|
Posted: Tue Jan 19, 2021 2:43 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Sodo wrote: |
MarkWard wrote: |
In theory, the grease you added could be creating friction. That's a stretch diagnosis. |
I have read often that too much grease will cause heat.
Its the 'stirring' of a viscous liquid.
It takes "work" to stir the grease.
The result is heat in the same way that brakes change friction into heat.
Imagine if you had to spin that bearing with a bicycle crank.
The heat is your Wheaties® burning and at some point you would feel tired.
Consider too that the excess internal pressure causes the seal lips to energize and bite down onto the seal lands, causing more friction (and perhaps a little more heat).
I doubt you've damaged anything yet.
I doubt the bearings are damaged (but they can be if you press them out)
I would scheme of a way to bleed the grease off. Can you remove the CV axle, and heat the housing with a torch?
Maybe heat-pressure without the 258 ft-lbs clamping will allow some grease to ooze out? |
I’ve always appreciated and understood the way you saw things like this. I agree that moving that thick grease takes effort, therefore creates heat at whatever RPM those wheels are spinning at. Not sure about bleeding some grease out, especially without damaging the seal itself. It’s super tight between the hub face and steering knuckle. I tried prying the seal back into place (since it got pushed out a little) but it just pushes back out. Heating the assembly to make the grease makes sense but I’m afraid that will damage the grease inside the bearings too, especially since it’d be hard to control...
I already ordered the replacement bearings and seals though. Because of all the the variables and unknowns, the risk of more damage to NLA parts, I’m thinking about redoing the bearings without grease for the sake of piece of mind. Maybe I’ll just do an inner surface lube of the bearing seals but nothing more. _________________ 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 |
|
Back to top |
|
|
MarkWard Samba Member
Joined: February 09, 2005 Posts: 17009 Location: Retired South Florida
|
Posted: Tue Jan 19, 2021 2:46 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
The bearings are sealed. No need to worry about them. For the inner and outer dust seal, a film of grease is all you need to keep them from tearing. Same with the rubber seal on the cv joint. Just a film. These are there to help protect the sealed bearing from contaminants that might find their way in. You want the CV and the hub seating on metal. No grease. _________________ ☮️ |
|
Back to top |
|
|
Sodo Samba Member
Joined: July 06, 2007 Posts: 9517 Location: Western WA
|
Posted: Tue Jan 19, 2021 2:56 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
T3TRIS wrote: |
I’ve always appreciated and understood the way you saw things like this. |
Good. You’re easy then.
Campfire, please!👍🏽👍🏽🔥🔥
With brakes, the amount of heat available can be endless.
In the case of grease, the heat softens the grease, viscosity is reduced, thus resistance is reduced, arriving at a steady-state (maximum) temperature.
Are you sure theres no passageway for grease to come out if the axle is out?
You can heat with a hot-air blower and use yout IR.
If just a little comes out thats no joy but perhaps enough.
But if a lot came out that would do it for sure. _________________
'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 |
|
Back to top |
|
|
T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
|
Posted: Tue Jan 19, 2021 3:02 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Sodo wrote: |
Campfire, please!👍🏽👍🏽🔥🔥.
Are you sure theres no passageway for grease to come out if the axle is out?
You can heat with a hot-air blower and use yout IR.
If just a little comes out thats no joy but perhaps enough.
But if a lot came out that would do it for sure. |
Yes please!!!
I’ll try to get some of that grease out first, I don’t have much hope though but I’ll try!
MarkWard wrote: |
The bearings are sealed. No need to worry about them. For the inner and outer dust seal, a film of grease is all you need to keep them from tearing. Same with the rubber seal on the cv joint. Just a film. These are there to help protect the sealed bearing from contaminants that might find their way in. You want the CV and the hub seating on metal. No grease. |
Thanks for the tips, I’m thinking this will work well. I guess I always find myself doing things twice (or 4 times with bearings I guess, left and right). I know how to get that inner race off quickly now though. I’ll try that heat method. _________________ 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 |
|
Back to top |
|
|
MarkWard Samba Member
Joined: February 09, 2005 Posts: 17009 Location: Retired South Florida
|
Posted: Tue Jan 19, 2021 3:09 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
No one is born an expert. I actually learn more when something doesn't go right. Its a learning curve just like anything. _________________ ☮️ |
|
Back to top |
|
|
T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
|
Posted: Wed Jan 20, 2021 8:46 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Alright, I just got back home and went ahead and removed the hub. Sodo, I considered trying to get some grease out by warming the hub and even trying to create a gap and using compressed air but it’s just too tight in there.
Anyhow, hub is off. It actually came off surprisingly easily with the press, which I’m not sure is a good thing or not. I can’t remember how hard the hubs and bearings were the first time around. The bearing is destroyed of course when removed.
I unnecessarily packed the outer sides of the bearings with STP hi-temp premium NLGI Grade 2 grease that has a dropping point in excess of 500°F. I really don’t know what all of that means but there it is. I was surprised to see that the grease on the outer side of the bearing had completely changed color from bright red to dark golden gray-ish. No idea if it’s from contamination or that the color changed because of temperature. There is about 140 miles on these bearings and just a handful of splashes in muddy puddles, nothing like a water crossing or sitting in water. The inner side of the bearing has grease that is still red.
I’m not entirely sure what to make of all this but here are photos.
Grease color differences (disregard the “gap” note, it’s actually the groove for the plastic bearing cage).
Grease color on inner side of bearing (still red)
Other bearing photos
I also just noticed that the inner race of this bearing is quite different than the one I removed a few weeks ago (image on left is a little stretched):
_________________ 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 |
|
Back to top |
|
|
Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
|
Posted: Wed Jan 20, 2021 9:58 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Not to take you off topic, but it will...
I noticed in one of your photos that you have the skid plate for the drive shaft. Have you got a skid plate protecting the Transaxle as well?
Reason I ask is that the Transaxle needs ventilation to run cool and people have found having the skid plate installed raises the Transaxle temperatures.
Okay back to topic. _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them. |
|
Back to top |
|
|
Sodo Samba Member
Joined: July 06, 2007 Posts: 9517 Location: Western WA
|
Posted: Wed Jan 20, 2021 10:00 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Are both bearings same width?
Kinda looks like bearing #2 ball tracks could be wider. _________________
'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 |
|
Back to top |
|
|
T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
|
Posted: Wed Jan 20, 2021 10:22 pm Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
Steve M. wrote: |
Not to take you off topic, but it will...
I noticed in one of your photos that you have the skid plate for the drive shaft. Have you got a skid plate protecting the Transaxle as well?
Reason I ask is that the Transaxle needs ventilation to run cool and people have found having the skid plate installed raises the Transaxle temperatures.
Okay back to topic. |
Ha! Nah our transaxle is exposed... I do plan on finding a way to protect things under there but it’s tough with the RMW engine bar. Haven’t really seen transaxle temperatures above 130°/140° expect in severe hot uphill. We drive pretty conservatively.
Sodo wrote: |
Are both bearings same width?
Kinda looks like bearing #2 ball tracks could be wider. |
I’m not too sure exactly what you’re talking about. Bearing #1 were the ones I removed with the initial front end rebuild but those have long been in the trash. _________________ 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 |
|
Back to top |
|
|
DanHoug Samba Member
Joined: December 05, 2016 Posts: 4715 Location: Bemidji, MN
|
Posted: Thu Jan 21, 2021 6:10 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
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. _________________ -dan
60% of what you find on the internet is wrong, including this post.
'87 Westy & '89 Westy both 2.1 4spd
Past projects can be found at--
www.thefixitworkshop.com |
|
Back to top |
|
|
MarkWard Samba Member
Joined: February 09, 2005 Posts: 17009 Location: Retired South Florida
|
Posted: Thu Jan 21, 2021 6:48 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
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. _________________ ☮️ |
|
Back to top |
|
|
11BC2 Samba Member
Joined: August 27, 2017 Posts: 494 Location: Cool, California
|
Posted: Thu Jan 21, 2021 8:48 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
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. |
|
Back to top |
|
|
MarkWard Samba Member
Joined: February 09, 2005 Posts: 17009 Location: Retired South Florida
|
Posted: Thu Jan 21, 2021 9:34 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
|
|
An old VW racer trick for FWD was to remove the factory bearing seals carefully and there was a fixture that bolted on both sides of the bearing, so you could pump in better quality grease. I never bothered on my car, it was just as easy to swap out bearings every season. _________________ ☮️ |
|
Back to top |
|
|
|