There are four adjustments and measurements that need to be made to properly set up a non-integral steering box:
This section deals with the Saginaw-design Ford Non-Integral Steering Box. This style box was used from the late 1950's on up to their replacement by rack-and-pinion systems. The non-integral refers to the box having no internal power assist and having no hydraulic lines connected to it. The power assist system, if there was any, was remote and separate from the steering box.
1 ) Input Shaft / Worm Gear bearing preload
2 ) Adjustment Screw to Sector Shaft end play
3 ) Sector Shaft to Rack Block gear mesh load
4 ) Sector Shaft movement degree-of-arc measurement (Optional)
These steps must be made in this order to correctly assemble, adjust and check the steering box. These are the steps outlined by Ford in shop manuals and technical bulletins for proper setup by a qualified mechanic.To make these adjustments requires the use of:
1 ) Direct-read (dial or digital) Torque Wrench capable of measuring 0-10 in/lb in 1 in/lb increments
2 ) Feeler shim gauges to measure .002"-.005"
It is important that Steps 1-3 be done in order as one step affects the next. If the first three Steps are made correctly, step 4 should fall within tolerance. Therefore, Step 4 is optional and needn't be done if you do not have the tools to do it..
Steering Box Adjustments & Measurements
For Ford/Saginaw designed non- integral style steering boxes
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Input Shaft / Worm Gear Bearing Pre-load: The end of the Input Shaft that is inside the steering box has a worm gear design. Both ends of the worm section have ball bearings that secure the shaft inside the housing and allow the shaft to rotate freely. The surface of the input shaft acts as the inner race to these bearings. The Input Shaft Bearing Nut tightens down into the box and tightens these bearings to the input shaft. This loads the bearings so that they are tight and hold the worm section of the input shaft securely. This bearing load must be sufficient to remove all movement and slack from the input shaft and yet loose enough not to have the bearings bind or wear excessively as the input shaft is turned. They must hold the input shaft in place as the steering action of the sector shaft places a deflecting action against it. This bearing load is determined by measuring the drag on the bearings as determined by rotating the input shaft.
WORM GEAR with INNER BEARINGS
Adjustment Screw to Sector Shaft End Play: The Adjustment Screw lowers the Sector Shaft into the housing and forces the Sector Shaft Teeth to mesh with the teeth on the Rack Block. This screw also sets the amount of end play of the Sector Shaft. This screw must have enough clearance to allow the Sector Shaft to turn without binding on the screw, but no so much that there is excessive end play in the Sector Shaft to affect gear mesh.
The clearance is adjusted by changing the shim located between the Adjustment Screw and the top of the Sector Shaft. Different thickness shims allow for correction of production tolerances and wear compensation.
Gear Teeth Mesh Load: The teeth on the Sector Shaft mesh with the teeth on the Rack Block, which is mounted to the Input Shaft Worm. The center gap on the Rack Block is designed tighter than the other gaps so that the center tooth on the Sector Shaft has a tighter fit when meshing with it. This tightness is designed into the center of the box because this is the position the box is most often in - steering the car straight down the road. This tightness in the center keeps the box tighter when going straight down the road so the car doesn't wander. The mesh load is determined by turning the steering box through its full travel and measuring the increased drag in the center of travel.
RACK BLOCK TEETH
The most common problem and complaint about steering boxes is the excessive amount of play in the steering wheel. It is not unusual for the steering wheel to move several inches without causing the tires to actually turn at all. While there are many reasons why this this can happen, the part most often blamed for this situation is a loose steering box. This section will address the steering box's role in this problem and how to resolve it.
Any looseness in the steering box will cause play in the steering wheel and steering linkage. Small amounts of excessive play in the box will cause larger movements elsewhere. Many things can cause play in the steering box: worn sector shaft needle bearings, worn teeth on the sector shaft or rack block, worn balls in the recirculating assembly as well as worn worm gear grooves. Over time the bearings inside the box also wear and become looser, adding to the problem. While the gear tooth mesh may contribute only a small part to the looseness of the box, it is this adjustment that can remove most of the play found inside the box. However, tightening this adjustment alone will only provide a temporary fix and can cause problems in the future.
There is only one proper way to adjust a steering box. To do this requires:
All internal parts must be in good condition. That is, the bearings must be in good condition, the tooth surfaces of the sector shaft, rack block and worm gear must not be excessively worn, the recirculating balls must not be worn down, and the bearing surfaces of the input shaft must be smooth and clean.
The steering box must have no outside drag imposed on it. Meaning, the pitman arm must be removed or the adjustment screw turned all the way out so that the sector shaft teeth are not providing any drag on the rack. The pitman arm must be removed from the sector shaft or the pitman arm disconnected from the steering linkage so that there is no drag imposed by them.The steering wheel and column must be removed so they add no drag to the input shaft.
The Input Shaft Bearing Load must be done first. For this measurement to be done, the adjusting screw on the top of the box must be turned all the way out to remove the drag of the sector shaft from the rest of the assembly.
The Gear Teeth Mesh Load can now be done until the correct total of center mesh load is obtained.
Measurement is done using a direct-read inch-pound torque wrench mounted to the end of the input shaft. The wrench measures the drag imposed on the input shaft by the adjustments. The proper loads are small and impossible to measure accurately without such an instrument.
That being said, here is the proper way to adjust the steering box:
Mount the torque wrench onto the end of the input shaft. On long shaft boxes this can be done by threading a large nut onto the threads that secure the steering wheel to the shaft and using the proper socket on the wrench. On short shaft boxes an 11/16" 12-point socket will usually slip over the splines and allow the shaft to be turned.
Measure the amount of drag needed to turn the input shaft. If the input shaft is in a more-or-less horizontal position, take the measurements while lifting the wrench to get a more accurate reading.
If the reading is less than 4 in/lb, loosen the Bearing Nut Lock Ring. Tighten the Bearing Nut and take another reading. Continue until you get a consistant reading of 4-5 in/lb of drag.
Once you have gotten the proper reading, tighten down the Lock Ring with a hammer and drift. Check the reading again. Sometimes tightening down the Lock Ring with tighten down the Bearing Nut, sometimes it will loosen it. Re-adjust Bearing Nut and Lock Ring until reading is correct with Lock Ring tightened down.
Slowly tighten down the Adjusting Screw while turning the steering box from lock to lock until you feel the box tighten while passing through the center of travel.
Lock down the Adjusting Screw and measure the increase in drag while passing through the center of travel. The drag reading should stay around the original 4-5 in/lb of drag until the center of travel is reached. The drag should then increase slightly and then go back down to the 4-5 in/lb reading. The desired increase at center is a total of 9-10 in/lb of drag.
Once the total drag has reached 9-10 in/lb at center, with the Adjusting Screw locked down, tighten the Lock Nut securely.
When checking for the gear mesh center drag, if the reading stays the same throughout the travel of the box, and the adjustment is turned as far as it will go, then the center teeth on the rack block and/or sector shaft are worn out and must be replaced.
If the drag reading goes up more than 2 in/lb just before you reach the end of travel on the box, then the Sector Shaft is dragging on the inside of the housing because it has moved too deeply onto the Rack Block. This indicates that either or both of the Sector Shaft or Rack Block are worn out and must be replaced.
If there seems to be two peaks at the center of travel and not just one, then the Sector Shaft and/or Rack Block are worn out and must be replaced.
Many people want to adjust their steering box while it is still mounted in the car, often without the accuracy of using a correct torque wrench. Sorry, but it just can't be done this way - properly. And since this is the way the engineers who designed the box intended for it to be done, this is also the way I recommend too.
I know, you have all heard from people who told you to tighten down the adjustment screw and that will take out all the slack - easy, no problems - hey, it worked for me!
Okay, maybe it did. It probably made some improvement, at least temporarily. But often the slack will come back. The amount of mesh load on the gear teeth is a very small measurement and can't be done without the correct torque wrench. I can set the load properly without one but that is because I have built hundreds of steering boxes and know how it feels. Still, I use a torque wrench for accuracy, anyway. It is very easy to tighten the adjustment far tighter than it is supposed to be. You will never feel it because the leverage of the steering wheel makes feeling such a small amount of drag impossible. This will cause the teeth to mesh under a much greater load and will accelerate their wear. That is why the slack comes back. Only now the gear teeth are really worn out and will have to be replaced. If the adjustment is really tightened down, teeth can actually break off of the rack block and cause the box to lock up.
The factory suggested measuring the bearing and gear mesh loads by attaching a torque wrench to the nut holding down the steering wheel, as in the picture to the right. This was after disconnecting the steering box from the steering linkage either by removing the pitman arm from the box or removing the linkage from the pitman arm.
Although this sounds good, it doesn't allow for the extra drag caused by the bushings centering the steering box shaft in the column, any drag of the steering wheel on the column or the possible drag imposed by the steering coupler.
If you must try to adjust the box in the car, without proper tools or in the wrong order, do so in very small increments and at your own risk!
A critical thing to remember is that the loads being adjusted and measured are actually very small. We are talking about inch/pounds
here, not foot/pounds like most torque values on the car. You must have a tool capable of measuring accurately to one or two inch/pounds, which you cannot tell the difference from by turning the input shaft by hand. Trying to judge bearing load and gear mesh by hand, you can easily over-tighten by a dozen inch/pounds or more. A torque wrench capable of accurately measuring in single inch/pounds is not a common or inexpensive tool, but is the only way to measure a box properly.
For examples of what can happen when a steering box adjustment is tightened too much, go to my Damaged Parts page.