It has been asked a few times on this forum whether a lockwasher was used at the front end mounting of the rear radius rod to the front end of the drive shaft tube. The order of assembly back to front as used from 1908 to at least 1920 for sure is as follows:
Radius rod
Single chamfer washer faced 9/16-18 hex nut (F/N 78) *jfr note - described as a lock nut in the parts books but shown in line drawing as a hex nut with chamfer on one side and likely a washer face on the other since it is shown as flat against the lockwasher surface which might then be explanation for why it was referred to as a "lock nut" since that was its function.
9/16 Dia. SPRING Lockwasher Plain (F/N 2823)
Drive shaft housing radius rod mounting ear
9/16-18 Threaded Castle Nut (F/N 77)
1/8 cotter pin (F/N 82)
These parts are clearly shown in top and side view line drawings of a 1911 chassis but also all 4 parts are called out in a June 1920 parts books as being used from 1908-1920 hence I believe the same assembly parts continued after the date of the parts book.
John,
It would sound reasonable for it to be assembled the way you describe. The castle nut uses the cotter pin as the "lock". The "single chamfer washer faced" nut would have a lock washer to keep it in place. After all, what else would "lock" it?
What I have experienced though is that the castle nut needs the lock washer under it in order to take up the space and allow the slots in the castle nut to do their job. I tried like you said on the last 1914 rear axle assembly I put together. I switched to the lock washer under the castle nut. This allows the castle nut to come up far enough on the radius rod to engage the cotter pin hole.
I don't doubt what you say is true. Using good engineering practices, it should be that way. I just have never found it to work.
Verne
A common misconception is that the rear rods pull forward ,when they actually push toward the rear. That seems to confuse folks. Or so I have found .YMMV
One point to think about is one flat of a nut or 1/6 turn will pull or push the center of the rear end about 5 thou depending on which nut is tightened.
Jack,
"A common misconception is that the rear rods pull forward ,when they actually push toward the rear. That seems to confuse folks. Or so I have found."
They really should do neither. Ideally, the torque tube & rear end assy. should be at perfect right angles, without any radius rod help. The radius rods are installed simply to maintain that alignment against the forces of driving, braking and rough roads. So, no initial "pre-load" should be required, either pushing or pulling.
But, as you say, "YMMV".
I'll admit, none of what I state is taken from any Ford literature. If you have any Ford instructions to the contrary I would like to see them. I'm not trying to be confrontational here, I want to know if I'm wrong in my thinking, according to Ford, and to learn.
Jerry, Yup! In some experimenting a few years ago I could stretch a 1/16 line through machined plugs end to end and put the rear end in alignment in the lay down position to within 7 thou. If I put about ten pounds down on the center every thing was in line to about 7 thou all done by radius rod adjustment.
Think many have been bent in the past with improper nut tightening.
So, thinking about this in my head (danger Will Robinson!); if your rear axle and torque tube are in alignment, without the radius rods, then the best way to not change that alignment when attaching the radius rods would be to put the castle nut on until it touches the bracket, then tighten the "plain" nut to the bracket. This should keep everything where it was before attaching the radius rods--right??
David
Yes. Correct way to do it, Ford Service Manual
(e) and (f)
While Fords method MAY have worked then, with everything straight, it won't work today. Ford is keying off the hole in the radius rods for the cotter pins. If the rear end housings are sprung, which most are, or if the torque tube or radius rods are bent, which many are, that method just won't work.
Seems to me the best approach once you get the rear end set up correctly is to hand tighten the nuts so you neither pull or push the backing plates, then slowly and evenly tighten things down with a wrench.
All that said, I don't think its that important to get the rear axle housings perfectly lined up. Usually there is of plenty clearance in the differential axle holes to allow for misalignment.