Model A Ford Brake Adjustment | DMAFC Workshop Notes

Objective and Brake Rod Configuration

The objective of this workshop is to assist you in accomplishing effective braking from your Model A, resulting in quick, straight ahead stopping with little to no pulling to either side. The diagram below illustrates the correct configuration of the Model A service brake components and rod connections.

Model A service brake rod configuration showing the front and rear rods, adjustable eyes, and cross shaft arm — Figure 1: Service brake rod configuration (driver side shown).

Before Adjustment

Disclaimer: No method of Model A brake adjustment will compensate for excessively worn components. All levers, pins, bushings, and brake linings should be inspected and/or repaired/replaced. All brake shoe springs should be replaced. For proper adjustment to be possible, it is assumed that the system is in good working order and that as much slop as possible has been removed from the entire system.

Many of us have used the method of brake adjustment using a pedal board fabricated with graduated notches to simulate foot pressure on the pedal, going through a series of differential wheel adjustments, resulting in a difference in front brake action vs. the rear brakes. See Figure 2 below.

Traditional Model A brake pedal adjusting board shown at the reference mark and with the pedal depressed two inches — Figure 2: Design and use of the traditional pedal adjusting board.

Alternate Pedal-Board Method

Today we will discuss and illustrate an alternative method of adjustment that is much simpler and easier to accomplish, resulting in the exact same braking from all 4 wheels. This procedure also uses a pedal adjusting board, but one with only a single notch to hold the pedal in the fully locked position. You may need to make a board for the correct length of your particular body style of car or truck. See Figure 3.

Alternate single-notch pedal board used to hold the Model A brake pedal at the two-inch mark — Figure 3: Use of the alternate pedal-board.

In this procedure, as with other adjustment methods, you begin by placing jack stands under both axles so all 4 tires are off the ground. Ensure that the levers attached to the brake cross shaft are exactly vertical. If they are not, remove the rod from the bottom of the brake pedal and adjust the clevis until the levers are in correct position.

Measure the brake pedal 2" up from the floor and mark that point with a piece of tape. This mark represents the point at which the brakes will be locked and the wheels should not turn.
Adjust your brake adjusting tool (board) so that it holds the pedal to the 2" mark when depressed.
With all 4 wheels off the ground, remove the clevis pins on all 4 brake rods and loosen the jam nuts. The adjusting clevis for the front brakes is at the front axle. The adjusting clevis for the rear brakes is at the brake cross shaft.

Front Brake Adjustment

Start by spinning a front tire...always in a forward direction. Turn the adjusting wedge clockwise until you feel a slight drag in the rotation of the wheel. Once you are satisfied with the position of the wedge on this wheel, you make no further adjustment to this wedge again. All further adjustments will be made with the clevis on the end of each brake rod.
Using your preset brake tool, depress and hold the brake pedal to the 2" mark on the pedal.
From the front of the car, push the front brake lever backward until the wheel locks. Adjust the clevis in or out to the point where the clevis pin slides in easily through the clevis and actuating arm.
Try to rotate the wheel. It should be fully locked and should not move.
If the wheel still turns at all with the pedal at the 2" mark, remove the clevis pin and turn it clockwise 1/2 turn at a time, testing it at each 1/2 turn until the wheel fully locks.
Remove the adjusting board and test the front wheel again. If it spins freely, adjustment for this wheel is complete. If it does not turn freely or there is too much drag, repeat the steps above until the wheel does spin freely with the brake fully released yet locked when the pedal is depressed to the 2" mark on your pedal.
If the wheel still turns at all with the pedal at the 2" mark, remove the clevis pin and turn it clockwise 1/2 turn at a time, testing it at each 1/2 turn until the wheel fully locks.
When adjustment of the first wheel is complete, you are ready to move to the other front wheel. It is done exactly like the first wheel as described above. When you are satisfied with the settings for both front wheels, you are ready to move to the rear wheels.

Rear Brake Adjustment

Whereas the front wheels are adjusted individually, the rear wheels should both be done at the same time. The reason for this is that the rear wheels are part of the drive train and drag from the differential makes it more difficult to achieve correct adjustment of the wedges on the backing plate.

With the rear service brake rods disconnected at the cross shaft, spin one rear tire until you feel and/or hear a small drag on the drum. You will have to use your judgment as to how much drag is acceptable in this stage of the adjustment procedure. Too loose will result in ineffective braking and too tight will result in overheating of the drum, also causing ineffective braking.
To test the wedge adjustment settings on both rear wheels, start the car and put it in 3rd gear (car still on jack stands). Let the car run in gear for a couple of minutes, then put the transmission in neutral and turn the engine off, allowing the wheels to slowly coast to a stop. Do not engage the brakes. The purpose of this step is to see how hot the drums are with the adjusting wedge settings you have chosen. Both drums should be cool to the touch or slightly warm. If you want to be more precise in your testing, use an infrared thermometer to give you an exact temperature reading of each drum.
If either of the drums is too hot, back off one click on that drum. Let the drums cool a few minutes, then test again by running the car in 3rd gear. When you are satisfied with your rear drum wedge adjustments, you are ready for final adjustment with the brake rods.
Position your brake tool to again depress the pedal to the 2" mark. Pull a rear brake rod forward until the wheel locks. Adjust the clevis as needed to allow the pin to be inserted through the clevis and brake cross shaft.
With the pin installed and the pedal at the 2" mark, the wheel should be locked. If not, turn the clevis clockwise 1/2 turn at a time until the wheel does lock.
Release the brake tool and check for free movement of the wheel. If it spins freely, you are done with this wheel. The adjusting procedure is the same for the other rear wheel.

Road Test and Final Checks

When all 4 wheel brakes have been adjusted, remove the car from the jack stands and take it for a test drive. The objective is to have the car stop straight ahead firmly with no pulling to either side. At 25 or 30 mph, take your hands off the wheel and push the brakes hard. All 4 wheels should lock up with no pulling either way. If there is pulling, take up an additional 1 or 2 clicks on the adjusting wedge on the front wheel opposite the direction of the pulling. Test again until the pulling stops and the car stops straight ahead.
Return to the shop and examine each drum. If any drum is hot to the touch, it is too tight and will cause excess drag while driving. Readjust any wheel with the brake rod clevis to allow cooler running. Once again, an infrared digital thermometer will allow you to have a better measure of heat in each drum and to make corrections to your adjustments more accurately. Go for a final test drive to ensure none of the drums are dragging and getting too hot.
When you are satisfied with all adjustments, tighten all 4 jam nuts against each clevis and install the cotter pins. These are metal to metal connections, so add to your routine maintenance list the need to periodically lubricate all clevis pin connections.

When all adjustments have been made, you can drive your Model A with the confidence of knowing your brake system will safely and reliably stop your car...even in an emergency stop situation.

Happy Model A'ing!!!

Bill Buckmeyer
Ft. Worth Model A Club/Dallas Model A Club
March 2021