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Discussion Starter #1
Our brakes require no more then .010 total runout shared between rotor runout plus wheel bearing play. The lip seal in the caliper starts becoming a air pump if flexed more then .010.
Originally GM allowable front wheel bearing clearance was .001 - .010 with .003-.005 prefered. If you go by this and the total runout can not exceed .010 you better have perfect rotors if your bearing clearance is .010 or the max allowed.
In 63 the Service Manual had us torque the bearing nut to 12 FT/lbs, back off the nut one flat and install the cotter key. .000-.007 was the range. In 71 the manual increased the clearance to .001-.008. Running at 000 clearance cost warranty problems.
The latest specs call for tightening the nut to 12 ft/lbs, backing the nut off till just loose, and what is just loose ? then hand tighten until a cotter key hole lined up. This should give .001-.005.

This is the proceedure I use and read alot of good things about.
1) While spinning the wheel in the forward direction tighten the nut to 15 ft/lbs. This sets the bearings, grease and race.
2) Back off the nut
30 While rotating in the forward direction retighten to 50-60 INCH pounds and install the key. This sets the bearings at .0005-.001.
But you say the cotter pin doesn't line up. I got luck and mine did but if not use valve shims. The type you use under the valve springs when setting up the heads. They come in different thicknesses.
Do not back off the nut.
So with the wheel bearing maximum run out at .001 and you shim the rotors which I will talk about later you end up with 2 or 3 thousand run out and the brakes do not pump air.
Got to go the kids are calling.
 

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At 50/60 Inch pounds on your front bearings you are going to burn them out , recomended at 12lbs , if you have rotor run out you need to resolve the problem change bearing ,rotor ,ect, not over tighten the bolt !
 

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Discussion Starter #5
clar2001 50/60 inch pounds works out to 4 to 5 foot pounds, that is why an inch pound torque wrench is used and can not be read by a foot pound torque wrench.
I have built my own rear axles from scratch and installed them dry with the proper clearance and then for the final assebly installed the seals and grease. Upon reassembly they would hardly turn, I mean really stiff but after a few miles they loosen up properly.
The method I gave you for tightening front bearings is not mine but something I read else, tried and am very happy with.
'The same things works for the back but is alot harder to do.
This is a shot of a homemade set of rear axles that I made to solve my twisting of the stock units. I do fully understand how to design , machine and install axles. These axles are a full 1 3/4, 4340, heat treated to 74RC , larger bearings and hopefully indistructable.
 

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This is a shot of a homemade set of rear axles that I made to solve my twisting of the stock units. I do fully understand how to design , machine and install axles. These axles are a full 1 3/4, 4340, heat treated to 74RC , larger bearings and hopefully indistructable.
[/B]
:surprised WOW! :surprised I wish I had your skillz....
 

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Discussion Starter #8
Thank you Patrick. I have been machining my own parts for about 36 years now. I do most of my own machining even on the engine or make nearly all parts.
In another 2 or 3 weeks I am getting my own machine shop and moving it to my existing shop behind the house. I work at a large university and use their equipment now but all that will change soon.
I also did alot of custom work for a large performance shop, then quit for a number of years but will start up again this winter.
I trust no one , or anything so I am constantly checking until I know it is right. I do research at the university and you learn to take nothing for granted.
I do not just slap parts together and hope, I prove their fit and design.
The RC of those axles is wrong, just noticed it. Should be 47RC.
 

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Discussion Starter #10
mga 74 would be extremely brittle, in fact off the charts. Even a cam in not that hard. My fingers must have gotten ahead of themselves and never picked up the mistake until this morning.
A spring is about 44 RC, a cam around 60 RC and after thinking about it chose 47 as a good area to be in. Hard enough for strength and wear but ductile enough not to break.
I do remove them once a year for inspection. That way everything comes apart easily.
I also believe in slip fit bearings, not the pressed on kind.
 
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