Calculating torque

[mike f]

I just dropped my axles to repair torn CV boots. I had purchased a 3/4" breaker bar and had no problems getting the axle nut off. Now for putting them back on and torqueing them up to spec. I need to get 217-231 ft-lbs of torque but don't have a wrench that goes that high. I can purchase a 3/4" torque wrench from harbor freight that goes 100-600 ft-lbs for about $70. I can't think of too many fasteners on the car that require that much torque. I have a wrench that will go to 150 ft-lbs that I use for wheel lugs, etc. Can I use simple math to solve my problem? If my son, at 135 lbs stands 20" out on a breaker bar (or a pipe extending the length of the bar) is that sufficiently close for this job? That would theoretically come out to 220 ft-lbs. Additionally, these are the castellated nuts which use a cotter pin, so loosening of the nut is not a concern. I am all for buying tools, but for a once or twice use type of thing I figure I could spend the $70 better elsewhere.

[project935]

Your son-on-the-bar method will be sufficient.

Spend the $70 on go-fast parts or your son for helping out.

[Grady Clay]

Mike,

Put it back together with the nut tight enough to hold and a cotter pin lightly in place. Drive by an automotive shop with the proper (3/4”) torque wrench and 30 mm socket. For a nominal fee (many won’t charge anything) you can have it set correctly.
Remember to bring new cotter pins and the tools to install.

Best,
Grady

[mike f]

Grady, that's an option I guess I never considered. Is the torque value on the axle that critical though? I have no idea.