Rear Axle Turning Torque

[ctaylor738]

Getting ready to install the pinion seal in the sedan rear end in my 280SL project.  The first step is to buy the correct beam type torque wrench to measure the force necessary to turn the rear axle.

The BBB gives a range of 20-25 cmkp to turn the rear end. 

1 cmkp = 9.8 Ncm, so 20 cmkp = 196 Ncm.

1 Ncm = .0885 inch pound, so 196 Ncm = 17.3 inch pounds

So, as my first step, I should buy or borrow a torque wrench with a 0-60 inch-pound scale.

Did I get this right?

 

[IXLR8]

Hi Chuck--

With the math you have described, it looks like the turning torque is about 1 1/2 foot lbs.

A foot lb torque wrench should turn the axle with very little effort.


Joe

[66andBlue]

Hi Chuck,
your math is spot on! Here is a handy converter: http://www.onlineconversion.com/torque.htm
Also kilogram and kilopond are for these purposes the same.

I was once told by an expert - you know him, he lives about 350 miles west of you  
"use a torque wrench in the 30 > 70% range because the lower and upper 30 are the least accurate"

So, a 0-60 lb-inch should be OK, provided it is a true 0,  and not a 20 - 60 lb-inch?

[DavidBrough]

When I did mine I purchased a small 1/4 drive inch pound beam torque wrench from a bicycle shop for about £10 and a couple of step ups to fit the pinion nut socket and it worked quite well.

[GGR]

If you find the right tool it's best using it. If not, I remember having done quite some calculations to determine the weight that should be hung to a rope turned around the input flange to apply the right moment corresponding to the specified torque.

Basically torque values are given in kgs applied to a 1 meter lever.

Moment is the force (or weight) multipled by the radius it is applied to. So if you need to apply 1mkg, and if the radius of the flange is 2cm you then need to hang 50kgs to apply the same torque value. In the case of the rear axle I remember I hung one full gallon of water in a milk container plus a few things else. Not very professional but it keept me going with what I had available at the time.