Light Switch Silencer

Three views showing the shape of the “silencer”.

The parts books show that in mid-1930 Ford introduced a small brass bushing, “A-3529 Steering gear lighting switch tube silencer”.  The bushing may have been used earlier (it was certainly needed) and overlooked in the parts lists.  It was formed from .006″ thick brass stock.  Listed as 29-31, it may have been intended for the Gemmer steering box only but probably well suited to the Ford steering box as well.

 The silencer installed in the top of a steering shaft.

The switch tube measures approximately .370″ in diameter.  The hollow center of the Gemmer steering shaft measures approximately .387″. That leaves over 1/64″ for the switch tube to rattle!  The compound shape of the “silencer” resulted in a springy, resilient bushing.  The lower edge was rolled inward to center the switch rod with minimal pressure.  The flange at the top functioned as somewhat of a thrust washer for the spring loaded switch tube assembly.  With all original parts it not only eliminates the rattle, but actually reduces binding of the switch tube.  If you have a replacement switch tube you will need to be sure there are no burrs or other problems at the top of the tube.

Model A Front Wheel Alignment

The following images and information are taken from the Ford Service Bulletins. Bulletins were sent to the Ford dealerships on a monthly basis.  Each contained eight to sixteen pages of service procedures, component changes, etc.  The original bulletins were 8-1/2″x 11″ pages.  The front page each month usually contained an image suggesting windows displays or other promotion ideas.

The Ford Service Bulletins are available in an undersized book form.  Unfortunately, the monthly cover pages were omitted to conserve space, but all the other pages are reprinted in their entirety.  A full sized version of the Ford Service Bulletins for the Model A years is once again being reproduced and I highly recommend it over the undersized version.

The bulletin states “Pull car forward at least three feet before placing gauge in position.  Place gauge between front wheels with ends of gauge bearing against the tires and both pendant chains (6″ long) barely touching the floor.”

“Test for play in bushings by pressing outward on the front of both front wheels at the same time.”

“Set the scale on the gauge so that the pointer registers at zero, then with the gauge still in place, move car forward until gauge is brought to a position back of the axle with both pendant chains barely touching the floor.  The pointer will now register the exact amount of toe-in.” April 1928





Additional Notes:

  • With the chains touching the floor, the gauge is 6″ above the floor.
  • No Model A wheels run perfectly true and as such have some degree of wobble. With the original gauge positioned and remaining in place throughout the process as specified, any wobble in the wheels is compensated for completely.
  • If it is desired to service the tie rod (spindle connecting rod) ends without moving the brake housing plates, in most cases it’s possible to access the end plugs by turning the steering all the way to one side and access the plug on the opposite side.  As a last resort loosen the clamp bolts and unscrew the rod. Both ends should release at approximately the same time. The rod ends may then be turned for access to the end plug.  In either case the toe-in will require readjustment.

When reinstalling, be sure the clamp bolts face the rear of the car, and that both ends engage the rod at nearly the same time.

  Measurement Changed September 1928

How To Apply This Information Today

 The wheel image to the left indicates some of the possible measuring points for setting the toe-in.  Points “A” are the points used following the original method and measurement (from 6″ above the floor).  The original specification of 1/16″ calculates to .194 degrees toe-in.

Using measuring points further from the center (spindle) slightly increases the required toe-in measurement to maintain the same degree of toe-in. Using measuring points “B” or “C” increases the toe-in measurement by 1/50″.  Using measuring points “D” increases the measurement by 1/27″. While the difference seems minimal, it’s important to keep in mind when making the final check.

Points “C” and “D” are for measuring at the tread surface (see “Suggestions” below)

The original method is the simplest and most accurate (short of more modern alignment equipment) but not everyone has an appropriate gauge.  Alternatives include multiple checks to average the different readings obtained from different positions of the tires, or raising the tires off the floor and applying a thin chalk line on the tread surface while slowly turning the wheel and using these lines for measuring points.  The latter also compensates for wobble as it applies to measuring and setting the toe-in.

Measuring points “B” and “D” (above) are potentially the best points to use but require a device with angled or offset ends that must NOT flex or distort during the process.  Measuring points “A” and “C” are the simplest due to the easy access.

Be sure to drive the car forward a few feet before the first and final checks.  The toe-in may be slightly increased (maybe an additional 1/16″) to add stability to a loose front end until proper repairs can be made.  However, this will increase the wear on the front tires.

Front End Shimmy

Will a loose ball in the front wishbone at the transmission cause a shimmy?  Yes, this could be one of the issues causing a car to shimmy.  A loose ball in the front wishbone can be one of the causes of front shimmy.  The front end caster (5 degrees) is dependent on the exact position of the front radius ball.  Make sure you have all the correct pieces to mount the radius ball to the bottom of the flywheel housing.  It should consist of an upper and lower cap, two spacers that fit through the mounting holes in the lower cap, two springs and two castle nuts.  If the assembly is correct and the ball does not fit tight, purchase or make a shim out of a thin fender washer, pounded to fit around the top half of the radius ball and reinstall the cap assembly. Then measure the front end caster.  Also make sure the tie rod balls are round and the drag link ends are screwed in tight enough — check Les Andrews Mechanics Handbook for specific settings.  Toe-in should be 1/16″ to 1/8″.  Also make sure the mounting bolts for the steering gear box are very tight.  Worn king pin and/or bushings can contribute as well. All these things relate to front end shimmy.  The most over looked and cause is incorrect front end caster adjustment.  This is determined by the position of the radius rod ball.

Two-Tooth Steering Column

One day while I was at Snyder’s Antique Auto Parts, a fellow asked me how hard it was to adjust the steering box.  It seems he was rebuilding a two-tooth box.  I told him, “There’s nothing to it.  Just follow the directions in the Model A Ford Mechanics Handbook.”  This brought laughs from those in the showroom, but there is a very understandable chapter on assembly and adjustment of the two-tooth box on pages Sect. 1-290 through Sect. 1-305.

If you just want to tighten up your steering, you can make three of the four adjustments without removing the steering column.

First adjustment:  Start by loosening the upper race jam nut on shaft end play bolt.  Tighten end play bolt until snug and then back off 1/8 turn.  Then tighten the jam nut and upper race locking bolt.

Second adjustment:  Start by loosening the jam nut on sector shaft end play screw.  With a stubby screwdriver, tighten sector end play screw and then tighten jam nut.

Third adjustment:  This is the most critical and delicate.  Jack the front end of your car up until both front tires clear.  Spin steering wheel to make sure it spins free.  Then with a 5/8” wrench, loosen the four housing cover nuts about one turn each.  With a 7/8” wrench, turn the eccentric adjusting sleeve nut clockwise to tighten.  Careful, a little bit goes a long way with this adjustment.  Spin the steering wheel lock to lock in place, making sure you don’t have a high spot.  If you do, you will know it.  Turn it counterclockwise to loosen.  With the steering aimed straight, wiggle the steering wheel while watching the front tires for play.  When satisfied, tighten the four housing nuts and recheck your adjustments.

This tech tip was originally provided by AJ Pennington and printed in the June 2002 “A” Quail Call.

Installing A Kill Switch

A twenty dollar item that can be a good safety device as well as a convenient tool is the kill switch.  Due to the battery being under the floor, you are limited to the type of disconnect that can be used.  The battery post type is not practical because you would have to fold back the mat and remove the cover plate to get to it.

The best one is the snap lock type that can be mounted above the starter or inside your A.  If you have a Coupe or Roadster, it’s easy to mount inside your seat riser.  Take the ground from the battery to the switch and from the switch to the ground.  Sedans take some imagination to install inside the interior, but it is most convenient there.

The simplest install is to buy the bracket from Snyder’s or other providers that mounts above the starter.  Take the battery cable off the starter and move it to the switch, then use a short cable from the switch to the starter.  You have to open the hood to access the switch but it’s an easy install.

If you ever had your starter stick, you can appreciate this switch.  Also, you will no longer have to remove the fuse.  You will just snap the switch.

When purchasing the necessary items for this task, you will need a disconnect switch, bracket and cable.  All three items should be available from your Model A vendor of choice.

This article was printed in the Jan/Feb 2007 issue of the “A” Quail Call by AJ Pennington.

Adding A Good Ground

A good ground is essential for proper operation of the electrical and ignition system.  A poor ground at the engine block and distributor can cause a weak ignition system and rough running engine.  A poor ground in the electrical system causes higher than normal currents to flow resulting in burned out light bulbs.  A poor ground to the starter causes a slow starting engine.

A good place to start adding a ground cable is at the battery.  Remove the ground from the battery at the frame, clean the area to bare metal and add a double eyed cable from there to a bolt on the transmission.  I have also added two cables from the frame to the bell housing on each side of the car.  This is also a good idea for those running float a motor mounts.

This article was printed in the Mar/April 2009 issue of the “A” Quail Call by George Allison.