1950 John Deere A steering box adjustment question

I am working on a 1950 John Deere A and have a question regarding servicing the steering box. How tight is the 1 5/16" castle nut supposed to be that holds the sector gear down. Is it supposed to be extremely tight in order to firmly hold the gear to the splines? Or is nut supposed to adjusted more like a wheel bearing system should be (i.e. hand tight and then back off a 1/8 or 1/4 turn or so) since this shaft also runs through the pedestal vertically as the main pivot axle. I have the parts list and owners manual, but can not tell if that lower bearing is a taper bearing or a roller type bearing so not sure how to tighten this nut.

FWIW: I have already searched and have found lots of helpful info in regards to servicing the gearbox. I have already pulled the sector gear for visual inspection and it was in surprisingly good shape. I re-installed the sector and adjusted the eccentric bushing and was able to remove almost all of the slop and everything still turns freely from to lock to lock. Worm shaft end play was good and did not need any adjustment.

Take it Home!

Field Service Bulletin 158-S, 9-15-47, the nut should be drawn against the washer tight enough to smash it into the recess provided for it as shown in the figure. If this is not done, after a short period of operation, the washer sinks into the recess allowing the steering shaft-to-sector joint loosen.

Actually, a new washer is recommended during overhaul. (PatB)

PBrowning: Thanks for posting the bulletin. It appears that I do not even have the proper washer as mine is flat only on both sides and my nut was loose which was the source of quite a bit of my slop. Luckily the gear still fits tight on the splines. (Shoulda known I was in for an adventure when I encountered the orange Silicone upon disassembly. Good news is that I think whoever installed the orange silicone also must have installed a new sector gear as it is in good shape and the worm gear looks good too. The tractor has Yetter power steering which I hear can be hard on both gears).

Three additional questions:
(1) Which way does the recess on the washer go? Your bulletin excerpt implies that the recess should go towards the nut, but to me it seems that it would make more sense for the recess to go towards the sector gear so that the washer would not bottom out on the splines before the gear is sufficiently tight.

(2) Do you know if this washer still available from Deere or an aftermarket company? If no longer available, do you know the measurement of the recess so that I can make one? (Depending on your answer to question number (1): Would simply installing a bigger shim washer that the I.D. clears the splines and the O.D. contacts the gear be a suitable replacement for the actual recessed washer - assuming the recess goes towards the gear like I am thinking it should?)

(3) Can you quantify "take it home": I realize Deere often did not provide torque values but they sometimes did provide a suggested wrench length to use when tightening a nut. Suggested wrench length indirectly serves as a poor man's torque wrench in the days when they did not exist and definitely prevents overtightening. (e.g. I have a 3/4" drive socket set that has long ratchets which would allow me to get it much tighter than say using a 12" length wrench).

Thanks again

The washer, part number A133R, doesn’t come up on John Deere “jdparts” site nor do I have its dimensions. When new, there would have been no concavity whatsoever – it would have been flat! It is rather soft really, and so I’d put it back on so that its center part sticks up against the nut. As you wrench it, it will change shape! Mallability (softness) is a part of the scheme here. Taking it home means a fair amount of torque – I’d probably use an impact wrench set between 125 and 150 ft-lbs. In layman’s terms, “gut-N-tight”! You will know the tightening is sufficient when the washer changes shape. The entire objective here is to ensure an interference fit of the splines between gear and vertical spindle shaft. (PatB)