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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Sat Jan 16, 2021 11:41 pm Post subject: Hot lug nuts and hub after Syncro front end rebuild [SOLVED] |
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Hello, I just wrapped up our front end late last night. Replaced all bushings, ball joints, bearings, installed lifted springs and new shocks.
Today we joined a rover group to do some off-roading. Drove about 120 miles, including lots of forest gravel roads and pretty gnarly off-roading (that lift is amazing). I noticed during the day, while checking the torque on the lug nuts that they were pretty hot. I didn’t think anything of it at the time.
Once we got back home, I hosed off the van (about 30min after getting home) and noticed that the front wheels were steaming and the water was drying from the center of the wheel. By the time I grabbed my IR thermometer, the center part of the wheel registered between 75° and 90° depending on where you measured. Outside temperature was around 45°. The brakes themselves were around 60°/70° (both front sides).
I drove the van again about 12 miles on the highway to dry it off. During that drive, I did a about 5 heavy brake test, toward the middle of the drive. The last part of the drive didn’t need much braking. I measured the temperature again and they were much higher:
- front wheel hub: 149°
- axle spindle: 139°
- wheel surface between lug nuts: 132°
- stud: 134°
- CV joint (close to the steering knuckle): 123°
- steering knuckle (next to CV): 105°
- brake rotor and caliper (both): 78°
- rear wheel spindle: 66°
Does this sound normal to anyone? I don’t seem to remember the nuts getting that hot in the past. People seem to blame the brakes or bearings. The brakes seemed pretty cool in these tests so I am worried about the bearings I just installed...
Anybody with similar experience?
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Update 1/22/21:
You can read the few pages of back and forth to figure this one out, however it would appear that the culprit was that I overpacked the bearings with grease on the outside of the bearings following recommendations from an online blog I had found. Our passenger side wheel hub was about 20º hotter than the other side when doing a short 10 mile drive test (without using the brakes). I replaced both front wheel bearings and they now seem to run at the same temperature. My best guess is that the grease I packed, which is unnecessary on a Syncro wheel bearing as they are sealed, had nowhere to escape when pressing the wheel hub into the inner bearing race. That grease created pressure on the outside edge of the bearing, pushing the plastic sealing cage into the ball bearings themselves, creating pressure, resistance, heat and problems. This post has photos of the removed bearings that clearly show compromised grease on the passenger side bearing. This post explains the grease pressures that I suspect damaged the bearings.
Bottom line: Don't pack the sides of your syncro front wheel bearing with grease!!! _________________ 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 Mon Jan 25, 2021 2:17 pm; edited 4 times in total |
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valvecovergasket Samba Member
Joined: October 10, 2018 Posts: 1491 Location: pnw
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Posted: Sun Jan 17, 2021 12:22 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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T3TRIS wrote: |
Does this sound normal to anyone? |
Not at all!
Are both front wheels doing this?
How do they free wheel if you've got them off the ground?
Steam when hosed down isn't right, and I probably wouldn't drive it until you sort out what's dragging, lest something get hot enough to melt or catch fire.
Get behind the wheels also and check the various rubber bits, 120 miles of this may not have done it many favors...
Over torqued axle nuts perhaps? Or improper install of the bearings? Those would be my first guesses if the brakes aren't dragging (and since they weren't messed with they're unlikely suspects)
Start with seeing how the wheels just spin when they're in the air it might be obvious _________________ MegaSquirt resource - SpitfireEFI.com
gone, but not forgotten: '83 tdi westy - swap thread |
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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Sun Jan 17, 2021 12:29 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Water boils @ 212° so guessing you having steam is getting a bit too hot.
An obvious question is what did you torque the axle nut too? It should be 258 ft. lb. if I remember correctly.
A not so obvious question is how much grease did you use on the bearing?
Assuming you used enough to lubricate it, but did you use too much?
The front axle bearing is a dual row of balls fairly close together in the same single assembly as you know. So it is kinda hard to over grease it like you could the axle bearings on the regular Vanagon that has an Inner and an Outer bearing separated by an open space. Sometime people fill all that open space with grease thinking it is better to have too much then too little. Doing that just allows the grease to churn like butter and insulate the bearing not allowing the heat to escape. So a bearing can overheat, but it takes hours to build up heat. You did drive all day, but just 12 miles I do not think it would have gotten that hot.
If you jack the front end up while cold and spin both wheels is the new bearing s harder to turn?
Also did you take a temp reading off the other wheel to compare temps? _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them. |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Sun Jan 17, 2021 12:43 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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valvecovergasket wrote: |
T3TRIS wrote: |
Does this sound normal to anyone? |
Not at all!
Are both front wheels doing this?
How do they free wheel if you've got them off the ground?
Steam when hosed down isn't right, and I probably wouldn't drive it until you sort out what's dragging, lest something get hot enough to melt or catch fire.
Get behind the wheels also and check the various rubber bits, 120 miles of this may not have done it many favors...
Over torqued axle nuts perhaps? Or improper install of the bearings? Those would be my first guesses if the brakes aren't dragging (and since they weren't messed with they're unlikely suspects)
Start with seeing how the wheels just spin when they're in the air it might be obvious |
Great... thanks. I’ll have to try tomorrow.
Here are things I did that I’m not sure could or could not contribute:
- I loaded both sides of the bearing with high temp grease as mentioned in this page. When pressing the hub on the first side (can’t remember which), some grease spat out and the seal seemed like it wanted to stick out ever so slightly. The hub still spun though with difficulty. Simone had mentioned that was normal just because of the tension on the seal.
- A long time ago I marked a breaker bar at 1.29ft because I weighed about 200lbs with clothes. I figured standing on it would give me the 258lb/ft of torque. I lost weight during COVID, believe it or not (probably 185lbs dressed), but instead of recalculating, I used the same mark and when the bar stopped, I just pushed downward a little bit more to add some weight. I can’t imagine I messed it up that much it would be considered the wrong torque... but who knows.
I’ll spin the wheels tomorrow and report back. In the meantime, I’d did spin the wheels while they were in the air before doing the driving today and they spun without much effort. That same wheel had a teeny bit of a brake pad drag, but I figured it’d center itself with the first hard brake (done early on purpose). Besides, I thought if the studs were that hot, the rotors should be just about the same but I could be completely wrong. As far as left vs right, in all honesty, I’m working on just a handful hours of sleep and I simply can’t remember if both front wheels were comparable though I seem to remember the wheels drying the same way. I mostly focused on one side for temperature measurements.
Anyhow, I need to catch up on sleep now and will get back at this tomorrow. Thanks as always for the help!
(Also, continuously impressed with what Syncros can do, and so were the rover dudes!)
Steve M. wrote: |
Water boils @ 212° so guessing you having steam is getting a bit too hot.
An obvious question is what did you torque the axle nut too? It should be 258 ft. lb. if I remember correctly.
A not so obvious question is how much grease did you use on the bearing?
Assuming you used enough to lubricate it, but did you use too much?
The front axle bearing is a dual row of balls fairly close together in the same single assembly as you know. So it is kinda hard to over grease it like you could the axle bearings on the regular Vanagon that has an Inner and an Outer bearing separated by an open space. Sometime people fill all that open space with grease thinking it is better to have too much then too little. Doing that just allows the grease to churn like butter and insulate the bearing not allowing the heat to escape. So a bearing can overheat, but it takes hours to build up heat. You did drive all day, but just 12 miles I do not think it would have gotten that hot.
If you jack the front end up while cold and spin both wheels is the new bearing s harder to turn?
Also did you take a temp reading off the other wheel to compare temps? |
Thanks for your inputs Steve. They align with my suspicions and valvecovergasket’s questions. I think my response to him is relevant to your questions. I’ll do more diagnosis m tomorrow. _________________ 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 10:31 am; edited 2 times in total |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9521 Location: Western WA
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Posted: Sun Jan 17, 2021 12:45 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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I'd quickly remove the wheel and squrt other stuff with that IR gun.
But it's cool now, and you'd have to drive it again. Can you decouple and spin that wheel? _________________
'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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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Sun Jan 17, 2021 12:47 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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T3TRIS wrote: |
- A long time ago I marked a breaker bar at 1.29ft because I weighed about 200lbs with clothes. I figured standing on it would give me the 258lb/ft of torque. I lost weight during COVID, believe it or not (probably 185lbs dressed), but instead of recalculating, I used the same mark and when the bar stopped, I just pushed downward a little bit more to add some weight. I can’t imagine I messed it up that much it would be considered the wrong torque... but who knows.
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Exactly. "Who knows" go to an Auto parts store and see if they will loan you a proper torque wrench. Or you might be safer to get a Harbor Fright torque wrench since you do not know if the parts store loan has been dropped. _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them. |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Sun Jan 17, 2021 12:51 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Sodo wrote: |
I'd quickly remove the wheel and squrt other stuff with that IR gun.
But it's cool now, and you'd have to drive it again. Can you decouple and spin that wheel? |
Thanks Tom, it’s definitely cooled down now and so am I!
I’ll decouple and spin tomorrow for sure. Also that image is super helpful, wish I had it before!! So we really don’t need to put grease on these outside of these bearings, huh? Would seem obvious but I think I was really misguided from this article... _________________ 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 Sun Jan 17, 2021 6:40 pm; edited 1 time in total |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Sun Jan 17, 2021 12:54 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Steve M. wrote: |
T3TRIS wrote: |
- A long time ago I marked a breaker bar at 1.29ft because I weighed about 200lbs with clothes. I figured standing on it would give me the 258lb/ft of torque. I lost weight during COVID, believe it or not (probably 185lbs dressed), but instead of recalculating, I used the same mark and when the bar stopped, I just pushed downward a little bit more to add some weight. I can’t imagine I messed it up that much it would be considered the wrong torque... but who knows.
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Exactly. "Who knows" go to an Auto parts store and see if they will loan you a proper torque wrench. Or you might be safer to get a Harbor Fright torque wrench since you do not know if the parts store loan has been dropped. |
I’ll have to do that I guess. Or invest in a little more than a little piece of electrical tape at 1.29’ on a breaker bar. But could I be that far off? It seems like I’m not the first one doing the weight thing? Or maybe it’s just that people recommend doing that “in theory...” it’s pretty sensitive to over torquing if that’s the case 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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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Sun Jan 17, 2021 12:54 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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I would not drive it until you break torque and re-torque it with a known value.
1 ft. lb. of torque is a 1 lb. of weight at the end of a one foot handle. You cannot get 258 ft.lbs. with a one foot long torque wrench unless your the HULK.
There are formulas to add extension bars to a wrench handle to get the right amount, but you'll have to Google search for them. _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them. |
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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Sun Jan 17, 2021 12:57 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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T3TRIS wrote: |
I’ll have to do that I guess. Or invest in a little more than a little piece of electrical tape at 1.29’ on a breaker bar. But could I be that far off? It seems like I’m not the first one doing the weight thing? Or maybe it’s just that people recommend doing that “in theory...” it’s pretty sensitive to over torquing if that’s the case too... |
The weight thing works, but you need to do the math to make it work right. Hence the formulas!
Nowadays it seems you can cheat and not break pencil points like the old days!
https://www.norbar.com/Home/Torque-Wrench-Extension-Calculator _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them.
Last edited by Steve M. on Sun Jan 17, 2021 1:00 am; edited 1 time in total |
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T3TRIS Samba Member
Joined: October 30, 2017 Posts: 299 Location: Portland, OR
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Posted: Sun Jan 17, 2021 12:59 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Steve M. wrote: |
I would not drive it until you break torque and re-torque it with a known value.
1 ft. lb. of torque is a 1 lb. of weight at the end of a one foot handle. You cannot get 258 ft.lbs. with a one foot long torque wrench unless your the HULK.
There are formulas to add extension bars to a wrench handle to get the right amount, but you'll have to Google search for them. |
Breaking it loose and re-torquing is a good idea.
However, if 1lb at the end of a 1ft bar is 1lb/ft, then 258lbs at the end of a 1ft bar is 258lb/ft. So... wouldn’t my 200lb of weight standing on a bar at 1.29ft be the same as if a 258lb person was standing on a bar at 1ft? Just the weight of our body. I seem to remember people claiming it’s actually quite precise... _________________ 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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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Sun Jan 17, 2021 1:01 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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T3TRIS wrote: |
Steve M. wrote: |
I would not drive it until you break torque and re-torque it with a known value.
1 ft. lb. of torque is a 1 lb. of weight at the end of a one foot handle. You cannot get 258 ft.lbs. with a one foot long torque wrench unless your the HULK.
There are formulas to add extension bars to a wrench handle to get the right amount, but you'll have to Google search for them. |
Breaking it loose and re-torquing is a good idea.
However, if 1lb at the end of a 1ft bar is 1lb/ft, then 258lbs at the end of a 1ft bar is 258lb/ft. So... wouldn’t my 200lb of weight standing on a bar at 1.29ft be the same as if a 258lb person was standing on a bar at 1ft? Just the weight of our body. I seem to remember people claiming it’s actually quite precise... |
See my edit...bed time on the East Coast! Did you spin the wheel slowly while torquing it? _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them. |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9521 Location: Western WA
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Posted: Sun Jan 17, 2021 1:09 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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None of this is making sense.
I can imagine "too loose" would allow rubbing and generate heat.
All of the grease is sealed inside the bearing.
Regarding the 258 ft-lbs: I cannot believe the torque being +/- 50 ft lbs would make any difference in heat.
Steve do you mean rotating the wheel (slowly) at the very early stages (less than 10 ft-lbs)? That makes some sense for ultimate ninja bearing assembly, but I can't imagine know how it could be related to the heat.
Take wheel and disc off, and turn it in the daylight, see if you can tell what's rubbing.
I think 149°F seems way too hot but I'd expect it to he hotter if causing damage. (fingers crossed) _________________
'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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Abscate Samba Member
Joined: October 05, 2014 Posts: 22568 Location: NYC/Upstate/ROW
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Posted: Sun Jan 17, 2021 4:47 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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95% it’s brakes rather than bearing. When were the fluid and hoses last changed on the caliper?
149F isn’t crazy hot for a disc brake but if water was sizzling rather than just steaming, it’s too hot. _________________ .ssS! |
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AceTaylor Samba Member
Joined: July 15, 2009 Posts: 137 Location: PERKASIE, PA
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Posted: Sun Jan 17, 2021 6:00 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Before you check temperatures again. Do the road test without the 5 hard stops. |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17014 Location: Retired South Florida
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Posted: Sun Jan 17, 2021 6:13 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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A brake disc can easily hit 1000 F. I’ve never fiddled with the grease in new bearings. I install them as they come out of the box. Drive it using only the hand brake. _________________ ☮️ |
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valvecovergasket Samba Member
Joined: October 10, 2018 Posts: 1491 Location: pnw
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Posted: Sun Jan 17, 2021 8:52 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Abscate wrote: |
95% it’s brakes rather than bearing. When were the fluid and hoses last changed on the caliper?
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Seems like odd coincidence, and he didn't mess with the brakes he messed with the bearings and axle
All the brakes I've ever had lock up stank like burning pads which is a pretty unmistakable smell. Meanwhile all the bearings I've misadjusted did exactly what he's describing... (Usually rear bearings on mk1s and mk2s in my younger days )
Based on what we know about how they were torqued my money's on overtightened axle nut. _________________ MegaSquirt resource - SpitfireEFI.com
gone, but not forgotten: '83 tdi westy - swap thread |
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Sodo Samba Member
Joined: July 06, 2007 Posts: 9521 Location: Western WA
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Posted: Sun Jan 17, 2021 10:04 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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T3TRIS wrote: |
installed lifted springs
...forest gravel roads and pretty gnarly off-roading (that lift is amazing). I noticed during the day, while checking the torque on the lug nuts that they were pretty hot. I didn’t think anything of it at the time.
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What is the distance from axle to fender lip?
20 inches is the max allowable.
At some number beyond 20" the CVs bind and get hot. _________________
'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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Abscate Samba Member
Joined: October 05, 2014 Posts: 22568 Location: NYC/Upstate/ROW
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Posted: Sun Jan 17, 2021 10:21 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Error analysis on your torque approach
Your foot is about 10 cm wide, and your 1.3 feet is about 40 cm long
Ergo have an uncertainty in torque of about 25% due to that method just from the length aspect
More importantly , stepping on a bar doesn’t put it in pure torque , there will be a downward reduction in force which will introduce torque loss.
Get a torque wrench for this application. _________________ .ssS! |
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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Sun Jan 17, 2021 10:35 am Post subject: Re: Hot lug nuts and hub after Syncro front end rebuild |
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Sodo wrote: |
All of the grease is sealed inside the bearing.
Steve do you mean rotating the wheel (slowly) at the very early stages (less than 10 ft-lbs)? That makes some sense for ultimate ninja bearing assembly, but I can't imagine know how it could be related to the heat.
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I'd forgotten that it is a sealed bearing.
It's not related to heat. It is related to torqueing a wheel bearing. _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them.
Last edited by Steve M. on Sun Jan 17, 2021 10:46 am; edited 1 time in total |
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