hmmmm preload all bearings? when i was going to college for diesel mech we put a dial indicator on the wheel bearing after doing the wheel bearing adjustment by the book. they had a specified freeplay, doesn't sound like it was preloaded at all. if you are trying to dissipate disc brake heat through the bearings those babies are going to go up in smoke about the first time you brake hard. we have a 91 explorer, the wheel bearings are very close together for some weird reason if you back off at all you have massive flop in the wheel? don't know haven't figured that out but tightened her up til freeplay was gone. so tight that the wheel doesn't free spin at all but runs good 40,000 miles since bearings never any prob? as to expansion the rotor may expand in diameter which would tend to make the outer race larger, but the expansion that concerns us is the other direction. the distance between the inner and outer bearing increases which forces the bearings more tightly into their respective races.

 

even separators are not rocket science. one old timer i worked for told me how he took a wheel bearing apart and the rollers all fell out, because the separator was worn out. the separator broke into bits. late night small town no bearing for 60 miles and a load of cattle on the trailer. he used slightly smaller old rollers from another bearing as spacers to separate the correct ones.set it all in place in grease and set his end clearance it ran normal for over 6 months of over the road transport at which time the already old rollers started show their age. he had only meant for it to make one trip but his brother in law didn't believe in fixing stuff that wasn't broke. more only free play aka endplay. the crankshaft in any engine will have at least main bearing will end thrust faces on it. if you wish to check when rebuilding an engine you set you dial indicator on the crank and force it back and forth. if the crank has no endplay or is endloaded against the thrust bearing you'll be lucky to get out of the shop before its totalled. thats personal experience there freshly overhauled silver 92 detroit broke in on dyno, but endloaded the crank on install. new block, new crank, and pretty much everything else too. having said that a plain bearing has to have some clearance at all times where a roller bearing ideally has no, or very little clearance once at operating temp. the plain bearing essentially hydroplanes, so it needs space for the lube to get in between. the roller by design has space where lube can get into the interface so it can run much tighter but too tight and the smoke will roll

 

Any new input on this subject? I am trying to learn .

 

I think with clean threads on the spindle and nut you have no preload untill the the inner bearing contacts the spindle and its race the outer bearing contacts its race and the washer under the nut., THEN if you tighten the nut any more you just get more preload.
It Really would be simple for the OEM's to publish a preload setting.
Don't know why they won't.

When I worked tech lines, I told people to set hyd lifter preload 1/2turn past zero lash. (that is either) .048 24 Threads per inch 3/8ths stud or .050 for 20 threads per inch for a 7/16ths stud.