Model A Ford: Rebuilding the 2-Tooth Steering Column

7-Tooth vs. 2-Tooth Steering Columns

There were 2 different designs of steering columns used during Model A production. The 7-tooth gearbox was used in 1928-29. In mid-29 the steering gearbox was redesigned to use a 2-tooth sector and worm gear. The changeover began in mid-29 so there is a possibility that a 1929 Model A could have left the factory with a 2-tooth steering column.

Primary Differences

• The housing for the 7-tooth column was cast all in one piece, whereas the 2-tooth design has 3 distinct and separate components: the sector housing, gearbox, and column housing. The removable parts of the 2-tooth column made repairs and/or rebuilding easier than on the earlier design. The 2-tooth column has more adjustments available than the 7-tooth.
• The 2-tooth steering column is 1" longer than the 7-tooth column.
• The 7-tooth column has a splined shaft steering wheel whereas the 2-tooth has a keyed shaft (woodruff key) steering wheel.

Early 7-tooth columns used a pair of roller bearings that had 9 rollers per bearing and fit into a race with a 25 degree bevel. The later 2-tooth design used bearings with 13 rollers per bearing and a 15 degree race. The parts in each of the columns are not interchangeable. Earlier style 9 roller bearings and races are not being manufactured today. Only the 13 roller bearings are available. What this means is that a bad 9 roller bearing or race will require that both bearings, lower race, worm gear, and upper race be replaced with the newer style so all moving parts are compatible.

Removal and Disassembly of the Steering Column from the Car

• No matter which column you are working on, both require removal from the car for overhaul.
• The starter must be removed to allow clearance for the column to come out.
• You can remove the column from the inside of the car or by pulling it out the bottom.
• Removal from inside the car requires removal of the pedals and battery. Loosen the pitman arm and pull it off the sector shaft.
• Loosen the 2 frame-to-box mounting castle nuts, then the column clamp on the bottom of the gas tank.
• You can tilt the column down to remove the light rod and steering wheel, or you can leave it in place until you get the column out and on the workbench.
• Removal from under the car requires removal of the steering wheel and light rod first. Jack up the front axle to allow adequate clearance for the column to be pulled downward and pulled from under the car.

Nomenclature and Identification of Steering Components

• Steering column housing (including locking collar and bolt/nut) - also called mast or jacket
• Sector shaft housing
• Sector shaft
• Upper race with adjusting bolt and locking nut
• Steering shaft - worm gear pressed on
• Gearbox
• Bevelled roller bearings (2) and lower race
• Upper column bushing
• Light rod attachment bracket - new modern oil seal plate

Disassembly of the 2-Tooth Column

• Loosen steering column collar bolt/nut and slide housing up and off the steering shaft.
• Remove 4 nuts/lock washers from sector shaft housing, noting the correct position of the single sleeve, then remove the housing.
• Remove the sector shaft and adjusting screw/lock nut from the gearbox.
• Release the upper race adjusting bolt, loosen the upper race clamp bolt/nut, and pull the race out the top of the gearbox.
• Steering shaft and lower roller bearing can then be removed through the top of the gearbox.

Inspection of Individual Steering Components

• Lower race will remain in bottom of housing - should be closely inspected for cracks, galling, pitting or other obvious wear. If in question at all, it should be replaced.
• Check bearing surfaces of both upper and lower ends of the worm gear for chipping, pitting or obvious wear. The worm gear is a very tight press fit onto the steering shaft, and it is a machine shop operation if replacement of the worm gear is required.
• Check sector shaft for abnormal wear.
• Sector shaft housing - originally used large bushings in each end for the shaft. Modern replacements for these bushings are needle bearings that will result in easier steering action and much better leak protection, especially when used with a machined-in modern oil seal in the end of the housing.
• Check condition of both tapered roller bearings.
• Check condition of threads on steering shaft for steering wheel attachment - care must be used as these threads are easily damaged or destroyed.

After a thorough cleaning and replacement of any required parts plus new gaskets, the gearbox and other parts are ready for reassembly.

Reassembly of the 2-Tooth Gearbox

1. Begin the reassembly with either good original roller bearings or quality replacement bearings. Using assembly lube, slide a roller bearing into the bottom end of the housing and mate it with its race.
2. Slide the 2nd roller bearing over the steering wheel end of the steering shaft and down to the top of the worm gear (taper facing up!).
3. Install the steering shaft into the top of the gearbox housing, mating the lower end of the worm gear into the lower bearing.
4. Install the upper race over the steering wheel end and push it downward into the top of the housing, making sure that the adjusting pad aligns with the adjusting bolt hole on top of the housing. Install the upper race locking bolt/nut but do not tighten yet.
5. Turn down the adjusting bolt to remove excess play (up and down movement) in the steering shaft. Note: Do not firmly tighten adjusting bolt at this time as this is only a temporary adjustment. Final adjustments will be made later.
6. With the sector shaft adjusting screw and locking nut removed from the gearbox housing, install the sector shaft (with brass thrust washer) into the gearbox and mesh it with the worm gear.
7. Place the sector housing over the sector shaft, aligning it with the mounting studs. Don’t forget the cork gasket for sealing the sector housing to gearbox. Note that the adjusting cone/sleeve mounts on the upper right stud. Firmly tighten all 4 mounting nuts. Install the adjusting screw and take out most of the play in the sector shaft with the adjusting screw and lock nut, but once again do not tighten firmly. Final adjustments here will also be made later.
8. A modern replacement end plate is recommended for a leakproof seal at the bottom end of the gearbox. The original style of seal was a flat washer and felt seal for the 600W oil, engineered to leak and not one of Henry’s better designs.
9. Install the steering column collar on the bottom end of the column housing, then slide the housing over the steering shaft and slide it down into position. The collar fastens the housing to the gearbox with a bolt, lock washer and nut. Fasten the bolt in place but do not tighten yet.

Reassembly is now complete and the gearbox is ready for adjustment.

Adjustment Procedures for the Rebuilt 2-Tooth Steering Box

There are 3 adjustments for the 2-tooth box:

1. Sector shaft end play
2. Steering shaft end play
3. Sector worm mesh adjustment

When any of the above 3 adjustments are made, the other 2 should always be checked in the order listed below.

Sector Shaft End Play Adjustment

• Turn the steering wheel to either stop, then back 1/8 turn.
• Move the sector shaft in and out to detect amount of end play.
• Use the adjusting screw to remove all play, then tighten locking nut.
• After adjustment, rotate the steering wheel from stop to stop to ensure free movement with no binding or obstruction of travel.

Steering Shaft End Play Adjustment

• Turn the steering wheel to either stop, then back 1/8 turn.
• Push and pull steering wheel up and down to detect any play in the column.
• If excess play is detected, loosen the gearbox housing clamp bolt, the column housing clamp bolt, and the upper race adjusting jam nut.
• Turn the adjusting bolt clockwise to eliminate all excess play, then back off 1/8 turn.
• Hold the adjusting bolt in desired position with a wrench while tightening the jam nut.
• Tighten the housing clamp and column clamp bolts securely.
• Again turn the steering wheel from stop to stop to test for free movement. If any binding is present, go through the adjusting process again.

Sector Worm Mesh Adjustment

• Locate the steering wheel to center position, or about 1 1/2 turns from either stop.
• For purposes of this adjustment, you can install the pitman arm onto the end of the sector shaft, or you can just use vice grips to achieve the same thing.
• With the steering wheel at center, try to rotate the sector shaft back and forth to check for play in the sector to worm mesh.
• Mesh adjustments are made with the adjusting sleeve nut (upper right housing stud). Slowly turning this sleeve moves the sector housing, resulting in a change of position of sector teeth to worm gear.
• Adjust sector mesh as follows:
  • Loosen 3 housing cover nuts and the 1 adjusting nut.
  • Slowly turn the adjusting sleeve nut clockwise while rotating the pitman arm back and forth to eliminate all sector shaft play.
  • After adjustment, tighten the housing cover adjusting nut first, then tighten the other 3 remaining nuts.
  • Rotate the steering wheel from stop to stop to ensure free travel with no binding.

After all adjustments have been completed, reinstall the steering wheel permanently, then slide the light rod down through the center of the steering shaft and out the bottom of the column...unless you plan on reinstalling the column from the underside of the car. When installing the light rod, don’t forget the small bushing that goes just under the upper plate of the rod.

Final Notes and Points of Discussion

• Overtightening any of the adjustments could result in breakage of some of the expensive parts within the gearbox, and will most likely cause binding and drag problems in the steering action. One last time, jack up the front end and turn the steering wheel from stop to stop to check for smooth movement of the steering wheel.
• Lubrication of the gearbox - John Deere cornhead grease and 600W gear oil.

  When restoration of the entire steering column assembly is complete and reinstalled in the car, fill the gearbox about 2/3 full with John Deere cornhead grease. With the front end jacked up, turn the steering wheel stop to stop several times to distribute the grease. The last step is to remove the grease plug on top of the gearbox housing and fill the rest of the box with 600W gear oil to the bottom of the fill hole. Reinstall the plug. Do not install a grease fitting!

  Note: Do not use axle grease in the steering gearbox.
• To reinstall the rebuilt column back into the car, no matter whether through the passenger compartment or from under the car, fasten the 2 bolts and castle nuts for the gearbox to frame rail fingertight, then install the column clamp under the gas tank. Firmly tighten the column clamp first then secure the 2 frame rail bolts and castle nuts. And don’t forget the cotter pins!
• Reinstall the pitman arm onto the end of the sector shaft using the correct special bolt and castle nut. Failure to use this hardened bolt and nut, substituting a cheaper grade of bolt for that hardened one, or failing to tighten the arm onto the sector shaft are on the list of possible causes of front end shimmy. It is easy to avoid this problem, and much safer, by using the correct bolt and castle nut, tightening it securely, and ensuring that a cotter pin locks it into place.
• The last test is to observe the pitman arm as small movements are made with the steering wheel. When the steering wheel is moved at all, the pitman arm should also move.
• If you have a 7-tooth steering column in your car that is in dire need of overhaul, and you are not a purist, it is generally advisable to convert over to a 2-tooth column. This is because the 2-tooth column has more precise adjustments available to remove excess play issues, and will result in better steering performance. There are many 2-tooth columns around and, considering the price of replacing expensive parts in your 7-tooth column, you can switch to a column that will provide an overall better driving experience for you in your Model A.