�66 lower ball joint nut torque confusion

[Gary B.]

[Tom E.]

[Gary B.]

[Gary B.]

[Joe L.]

I found the answers. First if all, there is no corresponding note in the ‘65 AIM. So the note for the lower ball joint nut torque in reference to the cotter pin first appears in the ‘66 AIM. The mystery is solved by looking at the ‘67 AIM, where the note has been revised to says “A torque of 125 ft-lbs is permissible on nut when slot is in correct position for insertion of cotter pin.” Now that finally makes sense. Also, the ‘67 AIM has a corresponding note for the upper ball joint nut, where the torque limit in the note is 90 ft-lbs. Obviously, by 1967 someone had realized the ‘66 AIM note made no sense and the 66’ AIM was lacking a note for the upper ball joint nut. Sometimes you need AIMs for several years to figure out these things.

Gary------


With the vast majority of fastening systems that include a slotted or castle nut with cotter pin, there will be a specified torque value and the instruction "plus additional torque necessary to insert cotter pin". This is very "standard".

Two exceptions I can think of: front wheel bearing nut and rear spring end bolt nut.

[Gary B.]

Gary------


With the vast majority of fastening systems that include a slotted or castle nut with cotter pin, there will be a specified torque value and the instruction "plus additional torque necessary to insert cotter pin". This is very "standard".

Two exceptions I can think of: front wheel bearing nut and rear spring end bolt nut.

Joe,

Can you describe the correct protocol for tightening the front wheel bearing nut for my ‘66? I’ve read the chassis service manual that says torque to 12 ft-lbs and then back off the nut one flat to insert the cotter pin. Any other tips?

The chassis service manual also says you can back off up to an additional 1/2 flat in order to get the cotter pin to insert. Does the 1 flat and then the 1/2 flat mean you must rotate the nut at least 60 degrees (1 full flat), but no more than 90 degrees, after torquing to 12 ft-lbs?

Gary

[Joe L.]

Joe,

Can you describe the correct protocol for tightening the front wheel bearing nut for my ‘66? I’ve read the chassis service manual that says torque to 12 ft-lbs and then back off the nut one flat to insert the cotter pin. Any other tips?

The chassis service manual also says you can back off up to an additional 1/2 flat in order to get the cotter pin to insert. Does the 1 flat and then the 1/2 flat mean you must rotate the nut at least 60 degrees (1 full flat), but no more than 90 degrees, after torquing to 12 ft-lbs?

Gary

Gary------


I tighten the nut by hand until there is zero end play. Then, I back the nut off whatever it takes to insert the cotter pin. However, if the cotter pin hole aligns at the hand tight position, then I back the nut off to the next position where the cotter pin aligns. The whole point here is to achieve proper bearing end clearance and with no preload. Specified clearance is to be 0.001" to 0.008". Have any concerns you got it right? Simply check the clearance with a feeler gauge after the adjustment.

By the way, some folks would like to get the clearance closer to the 0.001 than the 0.008. Unless one gets lucky, the only way this can be achieved is by reducing the thickness of the washer or nut. I do not recommend even attempting this. You can achieve the 0.001 to 0.008 using the procedure I described or the procedure in the service manual. I have tested this using a test set-up that I made to simulate the actual assembly. The approved clearance range is backed up by Timken. They know a little something about tapered roller bearings.

[Gary B.]

[Joe L.]

Joe,

I like the hand tight approach to get zero end play at the start. Just to be sure I’m thinking about this correctly, since the C2 spindle nut is 3/4”x20, turning it one turn would move the nut axially by 1/20” = 0.05”; turning the nut one flat, or 1/6 of a turn (60 degrees) would move the nut axially by 0.05”/6 = 0.0083”. So, using the hand tight approach, turning it about 15 degrees should get about 0.002”. Yes?

Gary

Gary-----


Yes. But, even if you have to move the nut 1 full flat (i.e. if the cotter pin hole aligns when the nut is hand tight) you'd still be in spec.

[Gary B.]

[Gary B.]

Gary------


I tighten the nut by hand ...

PS: And you do that hand tightening with just your thumb and two fingers?

Gary

[Joe L.]

PS: And you do that hand tightening with just your thumb and two fingers?

Gary

Gary------


Yes.

[Gary B.]