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Axle nut torque

Posted: Wed Jun 13, 2018 12:27 pm
by Jh911
Hi everyone-

I’m just finishing up my latest DIY- replacing a boot on a front CV axle on my 2003 Carrera 4 S-and I’m wondering what I should do to torque the axle nut. 340 lb/ft, right? My torque wrench is laughably undersized, and the local part stores who loan out bigger torque wrenches don’t have one that will handle such a high torque value.

It seems that over tightening the axle nut could lead to wheel bearing issues- so I don’t want to use the impact wrench I used to remove the nut.

Should I use math and calculate the proper length of breaker bar and then stand my body weight on it? Should I just use the impact wrench and be done with it? any other suggestions??

This project has taken me longer than I’d care to admit to get this far - kids, work, travel have all stretched this thing out to a 2-plus week project. This is the most challenging project I’ve undertaken so far on my car. It’s been extremely satisfying to do this on my own, and I want to make sure I complete the final step correctly.

Any suggestions would be greatly appreciated!

Re: Hope this helps!

Posted: Wed Jun 13, 2018 12:43 pm
by B3DAWG
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Re: Axle nut torque

Posted: Wed Jun 13, 2018 12:59 pm
by B3DAWG
IMHO... You can use an impact wrench to remove the main drive axle bolt, but use a proper torque wrench that will handle the 340 ft lb of torque. I agree NEVER over torque these bolts. And, using high rated impact wrench could greatly damage the wheel assembly.

Re: Axle nut torque

Posted: Wed Jun 13, 2018 3:00 pm
by 5chn3ll
If you don't have a 340 lb-ft torque wrench, just stack a 340-lb weight - plus a stack of the hard-back editions of all best-selling author, occasional Gitmo AirBNB guest, and internationally-renowned automotive fashion consultant John Ireland's books - on the end of a ratchet/extension combo that puts the weight exactly one foot from the pivot point (the centerline of the axle stud).

I don't have an appropriate torque wrench, but I can approximate it using a cheater bar and my somewhat-less-than-rail-thin physique. The nuts have not fallen off of the front wheels since using this technique, so it appears to be adequate for at least some applications.

If you're going to over-torque (i.e. guess at it), I'd over-torque with the cheater bar rather than the impact wrench. At least you'll have some vague feel for the bolt; with the rattle gun, who knows?

Re: Axle nut torque

Posted: Wed Jun 13, 2018 4:02 pm
by sweet victory
Another option if you don't have a torque wrench is use the following torque calibration spec for a 1/2" impact gun. 340ftlbs = 13 ugga duggas

Re: Axle nut torque

Posted: Wed Jun 13, 2018 9:30 pm
by Jh911
Thanks everyone for the replies and suggestions.

I went the cheater bar route with a (measured) extension and with my body weight on the end. I think my calculations got me close enough to the desired torque.

I’ll recheck it after driving around some just to make sure everything’s snug, but I feel pretty good about where it’s at now.

Really appreciate all the help from the community!

Re: Axle nut torque

Posted: Thu Jun 14, 2018 6:22 am
by Sneaky Pete
Jh911 wrote: Wed Jun 13, 2018 9:30 pm Thanks everyone for the replies and suggestions.

I went the cheater bar route with a (measured) extension and with my body weight on the end. I think my calculations got me close enough to the desired torque.

I’ll recheck it after driving around some just to make sure everything’s snug, but I feel pretty good about where it’s at now.

Really appreciate all the help from the community!
That iswhat I did. Used a breaker bar with a pipe extension and did a calc for the measurement of how long the extension should be. Got my 215 lb body on the end and hopped up and down a few times. Good job.

Re: Axle nut torque

Posted: Thu Jun 14, 2018 1:28 pm
by B3DAWG
Jh911 wrote: Wed Jun 13, 2018 9:30 pm Thanks everyone for the replies and suggestions.

I went the cheater bar route with a (measured) extension and with my body weight on the end. I think my calculations got me close enough to the desired torque.

I’ll recheck it after driving around some just to make sure everything’s snug, but I feel pretty good about where it’s at now.

Really appreciate all the help from the community!
Curious, what year 996? Does your axle bolt have a cotter pin on it?