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OK so you guys are probably thinking "why did anyone suggest he use a heat sensor?" but this may be my last question for now.

I had changed the front bearings recently but I don't have a torque wrench that goes down to 12 lbs so I bubba'd it. It's been years since I did this and I was worried that maybe I'd gone too tight, so guess what I did? Yup, I shot them with the infrared. Immediately after a 15 minute drive, I got about 105 degrees at the hubs and bearing nut so I think I'm OK?
 

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OK so you guys are probably thinking "why did anyone suggest he use a heat sensor?" but this may be my last question for now.

I had changed the front bearings recently but I don't have a torque wrench that goes down to 12 lbs so I bubba'd it. It's been years since I did this and I was worried that maybe I'd gone too tight, so guess what I did? Yup, I shot them with the infrared. Immediately after a 15 minute drive, I got about 105 degrees at the hubs and bearing nut so I think I'm OK?

My '82's shop manual says to tighten the nut until it gets snug..........then advance it just far enough to put the cotter key in. Remember, pinion bearings are pre-loaded to a turning torque of 15 to 25 in/lbs and they do just fine. I would think 105 degrees wouldn't be any concern as your tires are most likely getting that hot too. Now if you were getting a temperature of 300-400 degrees I'd be concerned. Then remember this little fact: Steel expands approximately 1/8" for every 100 feet when it gets heated. As your spindle bearings are about 4" apart from each other they will separate slightly as the spindle gets hot..........making your bearings looser. Whenever I adjust my wheel bearings I always tighten them REAL tight (maybe 50 ft/lbs). Then I back the nut off and then snug it up again just enough to insert the cotter key.
 

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My '82's shop manual says to tighten the nut until it gets snug..........then advance it just far enough to put the cotter key in. Remember, pinion bearings are pre-loaded to a turning torque of 15 to 25 in/lbs and they do just fine. I would think 105 degrees wouldn't be any concern as your tires are most likely getting that hot too. Now if you were getting a temperature of 300-400 degrees I'd be concerned. Then remember this little fact: Steel expands approximately 1/8" for every 100 feet when it gets heated. As your spindle bearings are about 4" apart from each other they will separate slightly as the spindle gets hot..........making your bearings looser. Whenever I adjust my wheel bearings I always tighten them REAL tight (maybe 50 ft/lbs). Then I back the nut off and then snug it up again just enough to insert the cotter key.
That is 1/8"/ 100"/°F True. The spindle will expand, but at the same time the hub is also expanding negating the effect. I guess if you really wanting to know if the bearing was get tighter or looser with heat you would have to compare the expansion rate and temperature of the steel spindle with the expansion rate and temperature of the cast iron hub. Sounds like Calculus to me.
 

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That is 1/8"/ 100"/°F True. The spindle will expand, but at the same time the hub is also expanding negating the effect. I guess if you really wanting to know if the bearing was get tighter or looser with heat you would have to compare the expansion rate and temperature of the steel spindle with the expansion rate and temperature of the cast iron hub. Sounds like Calculus to me.

As the spindle and hub warm up the distance from the outer and inner bearings increases very slightly..................loosening them. Maybe 1/4th of a thousands of an inch at the very most. The engineers know the bearings will slightly loosen and that's why they call for the small 12 ft/lb pre-load. Tapered roller bearings will withstand a considerable pre-load as pinion bearings (in cars) call for a "turning torque" of between 15 and 25 in/lbs. But I have also run wheel bearings slightly loose (a half of one hex) with no problem.
 

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I recently got some front tires for my '71 and upon putting my car up on the hoist the idiot kid wiggled my tires/wheels and told me I needed front end work. I explained to him he was feeling the amount of clearance between the diameter of the spindle and bearings. He gave me a dumb look like "huh". I explained to him the spindle is machined slightly smaller than the bearing's inside diameter so no matter how hard the bearings are tightened there will always be a certain amount of play. "Oh" he said. "I wasn't aware of that".
 

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You can use a dial indicator too. Set them up with .0015-.002 end play. I've done that several times and never had any problems. Tight, but loose enough you can just feel the movement.
 

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Discussion Starter #7
So is it OK to go back and loosen them up a bit after they have been run at the current tightness?
 

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One thing to remember is: a freshly greased bearing will run hotter than normal. Or hotter than one that has not been freshly greased. Once the lubricant gets evenly distributed the bearing will return to normal operating temp. On occasion i've seen guys load so much grease onto bearings they blow out the seals, run hot and make a mess. :duel:
 
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