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Steering Box Rehab - Recovered PeppyDan Article


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November 19, 2018 ·  Mark this topic read · Report post

Here is a how-to for the 700-900 series A.C. & the 3300-7100 series Simplicity steering boxes. It seems that most of the troubles I have had with hard steering tractors can be narrowed down to two problem areas. One is the front spindles and the other is the steering box bushing. powerking_one has a very nice fix for the spindle problem so I'll provide a link to his topic on the spindles:  


I am starting with a cruddy old steering box that once removed from the tractor required a visegrip to turn it from lock to lock.


First I disassemble the unit by removing the nut and washer holding the bevel gear to the steering arm assembly.




Then I remove the C-clip from the steering shaft and remove the bevel pinion. This is usually a light press fit and required tapping the steering shaft out of the bevel pinion using a drift punch or bolt to prevent mushrooming the end of the steering shaft.There is a key on the shaft that will clear the bushing with out any problems so don't worry about that for now.





Then I removed the steering plate & the bushing. The bushing is a press fit and also required tapping it out with a pipe or deep well socket.





The shaft was very rusted so it got polished in my lathe. I then drilled and tapped (1/4-28) a hole in the end of the shaft approximately 1 1/2 inches deep using a #3 drill bit. Please note that I did leave the key in the shaft while machining it only because it would not come out. I made sure to use extra precautions to prevent myself from getting hit if it were to come out during the machining process!id="red">








I then cross drilled it in my drill press 1/4 inch from the shoulder using a 1/8 inch drill bit and countersunk both sides to remove any burrs. after this I used the # 3 drill bit by hand to remove any shavings left from the cross drilled hole.



Now to make the new bushing! The original bushing was made of a cast metal and would easily break during the machining and assembly process(been there done that) so I used a piece of 1 1/8 O.D.-3/4 I.D. tubing for the new bushing. I first machined it to a length of .150 shorter than the original. This is to allow for the thrust bearing and washers later. I then drilled the tube to 7/8 inch to give relief for the shaft and allow the bearing to make the only contact. I then bored the tube to a diameter of 1.000 to allow the bearing to have a light press fit to slip fit only slightly deeper than the width of the bearing. If needed it can be locktighted in using removable locktight! (2154258SM bearing needle $3.65 at Jacks)This is the same bearing that is used in the steering arm shaft of the steering box (Simplicity 154258) so if you have a spare box you can use one of those like I did!




Now we need to remove approximately 1/8 inch of material from the steering housing assembly to give the clearance needed for the thrust bearing & washers. (Don't forget to do this before you press in the bushing or you will have to remove it like I did!) Then using a vise press the bushing into the housing with the bearing towards the side for the gears. Final adjustments will be made later.





Things can now be cleaned and painted if needed. I used a wire brush on my grinder to clean the gear teeth. Just one more thing to modify before it goes together! One of the two thrust washers will need eyebrows ground into it similar to powerking_one's modification for the spindles. These are some of the same part numbers for the spindle modification also. It will require 2 thrust washers Timken/Torrington(TRA1220) & one thrust bearing(NTA1220) to complete the steering box only!



To assemble things back together, install the steering plate first, then install the steering shaft(I put a little grease on the bottom of the set collar), next is the modified thrust washer followed by the thrust bearing, and then the last thrust washer. If all machining is correct the shafts shoulder should just be exposed to allow the gear to seat against it.


Now comes time to press the bevel pinion back on to the steering shaft. This can be done several ways including heating the gear slightly and freezing the shaft or by tapping the gear back on using a pipe or socket to protect the shaft. If you removed the key don't forget to install it first! after the gear is on reinstall the C-clip.


Line the marks on each gear to properly install the bevel gear and the steering arm assembly. Next tighten the nut on the steering arm assembly.


Adjust the two bolts on the steering plate to properly mesh the gears without binding and tighten the jam nuts. Grease both zerks until grease starts coming out and the steering box is ready for years of service with only a few shots of grease each year.



Edited by PhanDad
Fixed powerking_one PMPS Link
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I have done this on three steering sectors & can't stress how much more of an improvement this is vs the Poor Man's Power Steering upgrade to the RBTs.  The only thing I did different was to use a Bronze sleeve in place of the Tubing @PeppyDan used in the original write up.

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