Restoring the Ford Model A - Seven Tooth Steering Box

Ford Model A - Seven Tooth Steering Box

My Ford Model A has a Seven Tooth Steering Box which was used in the 1928/29 model. This steering box is not the best construction and is the cause of oil leakage and hard steering. This is the reason why I have modified the whole steering box and made it much better than Ford has made it originally.

The idea to this modification is not from me but from Bob Barnes, Stratford, Connecticut. Bob has described all these Modifications in the September / October 2002 issue of 'The Restorer' (Club magazine of the MAFCA ). Bob has also supported me by sending blueprints how I have to make the conversion to needle bearings. Many thanks Bob for your help and support and as you can see everything worked fine!

Three of all four modifications are visible on this picture. On top of the picture you see the steering column end plate with the an additional O-ring. On the right is the Steering shaft felt retainer with an additional tube and at the bottom are the two needle bearings.

The fourth modification is made at the steering box itself. I have moved the original grease fitting by one inch to the right side (up). With this change you can fill more oil into the steering box and the steering bushing is better lubricated.

This hole had to be enlarged by a machine shop in order to install new needle bearings.

Here you see the version with needle bearings on top and with the original sector bushings below.

The needle bearings are pressed in.

Here are both on its place.

The self made distance tube is not really necessary but I wanted to be on the save side.

Finally the seal is pressed in.

Then the steering shaft with the steering worm and the bearings are inserted.

The end play is adjusted with brass gaskets

I have supported the steering column end plate with an O-ring to prevent oil leakage.

When there is no end play anymore of the sector shaft, the 7 tooth sector can be inserted.

When you mount the steering column end plate, use a gasket sealer.

Put also some Loctite to the threads of the three bolts.

When the plate is mounted, the end play can be adjusted.

This steering shaft felt retainer is available from Bratton's and is the last piece in the puzzle to make the steering box leakage free. In the lower part of the picture you see the original item. It may be necessary to enlarge the hole in the shaft a little bit so the tube will fit into the hole.

Then the spark and gas rods can be mounted.

Don't forget the steering shaft felt (anti rattler).

Finally the two control arms can be riveted to the rods.

Then you can fill the box with 600W oil and I'm confidential that I will never have any trouble with my steering box.

Source:  http://www.maurer-markus.ch/ford_a/mod_lenksaeule.en.html

Model A Ford Steering by Neal Anderson

Model A Ford Steering by Neal Anderson

From Judging Standards: There were two types of steering assemblies used during the years of the Model A production. The first was the Ford designed 7-tooth gear, eventually replaced by the Gemmer design 2-tooth steering gear.

The 7-tooth type is correct for all vehicles through March 1930. The 7-tooth column can be identified by a plain lower housing with only a lubrication fitting on the upper side. A second Alemite fitting was added to the housing over the sector in September 1928. This second fitting was used only on the 7-tooth assemblies. The 2-tooth assembly first appeared in February 1929 and continued to the end of production. The 2-tooth column had either a 1/8” lubrication fitting or a pipe plug on the steering gear housing until October 1929. Thereafter, a 1/4” NPT pipe plug was used.

There were five different castings used for the 2-tooth gear housings. The first had the words “Gemmer” and “PAT.PDG” in raised letters on the outer surface (don’t have). The second type had the “Gemmer” and “Pat.Pend” indented in the surface. Both the first and the second appeared in February 1929. The third type had “Gemmer” and “Patended” indented in the surface and was used from April 1929 thru mid 1930. Each of the first three had a large raised “F” on the engine side. The fourth type had no identification except an indented “A-3550-C” on the engine side. The fifth style was the same but had a raised , 5/16” or 9/16” letter “F” on the outer side. Both the fourth and fifth were used from January 1930 thru the end of production.

Instructions for Judging: When judging the steering function, the desired condition is firmness without binding. Since the entire steering system is subject to constant movement, the resulting wear will be apparent when the steering wheel is moved from side to side. No appreciable looseness should be tolerated. There should be no more than 2 inches of free movement. The column should not rotate or move in the frame. The steering wheel should be tight on the shaft and have no up or down movement. No oil should be detected on the light switch housing nor should there be evidence of oil leaks from the sector housing. No gasket was installed between the bail plate and the gear housing. There should be no cracks on the steering column where the lower ends of the throttle and spark rods extend.

7-tooth
A number of years ago, Paul Carlson and Chuck Maas gave a clinic presentation on the 7-tooth steering gear box. It is in the Clinic Overhaul Manual. It contains every thing you need to know about the 7-tooth assembly.

2-tooth
Also, in the Clinic Overhaul Manual is a handout by Chet Larson. Overhaul of the 2-tooth steering assembly.

Adjustment for the 2-tooth Steering Column (Out of Car)

There are three basic types of adjustment:
1. End play of steering shaft.
2. End play of the steering sector.
3. Alignment of the sector gear teeth in worm gear

It is advisable when making these adjustments to follow the procedure in chronological order. Steering column removed from car and all repairs completed.

1. For adjustment of end play in the steering shaft turn the steering wheel to the extreme, then back 1/8 turn. By loosening the housing clamp bolt which is located on the backside of the steering column and by releasing the jam nut, the thrust screw can now be screwed downward thereby pushing the upper bearing assembly and bearings down toward the worm gear. Make sure you have turned this adjustment down tightly. When re-tightening the jam nut, back off approximately 1/6 of a turn on the thrust screw. Make sure you secure the housing bolt. Turn steering wheel from lock to lock and be sure there is no binding.

 

2. To adjust the end play in the steering sector turn the steering wheel to the extreme, then back 1/8 turn. (If replacing the original steering sector shaft, make sure the is no worn spot on the end of the shaft and also on the thrust screw – see example). Be sure that all housing bolts are tight. Loosen the jam nut that secures the thrust screw on the side of the housing. Using a screwdriver turn in a clockwise direction until screw is snug. Turn the steering wheel from lock to lock being sure there is no binding

3. The last adjustment is for alignment of the sector gear teeth in the worm gear. This is the most complicated of the adjustments to make. Temporarily install pitman arm on sector shaft. The worm gear and sector teeth are machined in such a way that a close mesh occurs only at the central position. This corresponds to straight ahead driving range, with the tolerance increasing towards the extremes of the worm gear. Shake the pitman arm to determine the amount of lost (looseness) motion. Start by turning the steering gear to the center position of its travel. Loosen the hosing cover nuts 1/4 turn and the eccentric sleeve jam nut 1/2 turn. Turn the eccentric adjusting sleeve clockwise very gradually, checking at each movement the amount of lost motion in the pitman arm. Adjust to the point when lash can just be felt at the pitman arm, being sure to always bias the eccentric sleeve in the clockwise direction. Check by turning the steering wheel through its full travel. If it is too tight, turn the eccentric sleeve in a counter-clockwise direction until the gear is free and make the adjustment again more carefully. Next, check for tooth contact centralization. In making this adjustment, the check must start with the sector shaft teeth meshed at the central position of the worm gear. The center position is found by turning the steering shaft to the center position of its travel and locating the keyway in line with the worm adjusting screw. Turn the steering shaft 1/2 turn to the right and shake the pitman arm and note the amount of play at this point. Now turn the steering shaft 1 complete turn to the left and shake the pitman arm. The lash should be the same as when turned to the right.

Re-install steering column in car.

Steering Sector Housing Needle Bearing.
Bratton’s can have your sector hosing machined and needle bearings installed. Before installing the sector shaft through the housing, smear some grease on the seal and the thrust washer.

When filling the rebuilt steering gear box with oil after it has been installed in the car, don’t over-fill it. Put in just enough gear oil (about 4 1/2 ounces) to cover the worm, as seen down the filler hole. If you fill it to the top, gear oil will leak out the back of the gear box around the upper bearing cup until it reaches its level. Use only 600w gear box oil (never chassis grease – the worm, sector and bearing must have an oil bath). You can add a little STP or equivalent to make it slicker and a little thicker, but never STP alone. 

Source: http://www.tcmafc.org/index.php?option=com_content&view=article&id=108&Itemid=101