Early Ford Drum Brake Conversions 1932-1948


To understand the how we will have to to start with discuss the why. Brake technologies has designed pretty a couple advances in the previous one hundred yrs, but even again in the nineteen forties, Ford adapted modifications to the way brakes ended up made, a lot to the resistance of Henry Ford.

Henry Ford was fond of his mechanical brakes, and his advertising touted “Reliable metal from pedal to wheel”. These mechanical rod operated brakes persisted right until 1939, well driving Ford’s competitors. The problem with the brakes is that they essential recurrent adjustment, and ended up just plain risky at speed. They showcased 12 inch diameter drums that could quickly place a car into a spin if one particular brake rod was tighter than a further. Significant speed stops proved to be hair increasing experiences, and lots of felt that the new hydraulic or “juice” brakes released in 1939 to the Ford item line was a phase up in security and performance.


The to start with and by much the most critical style enhancement was the alter from rods to hydraulic fluid to actuate the brake footwear. While the style was initially invented in 1924, Ford resisted utilizing the style right until 1939, with the backing plates, footwear, and drum assembly that in lots of ways the is very same style utilized on vehicles nowadays. There ended up a couple important style troubles that took some yrs of manufacturing to be acknowledged and enhanced on. Alongside with other idiosyncrasies, Ford’s new adopted hydraulic style was a work in progress. The brakes essential much more pedal energy to end the car than our modern drum brakes, a crack in period of time, and even in some cases machine grinding to in good shape the right way.

Again in the 1940’s and 1950’s our warm rodding fore-fathers experienced minimal resources and little obtain to sophisticated equipment, so generally a “bolt on answer” was the most common. From the way Ford made their vehicles, these brake possibilities ended up just that.

The next major style enhancement was the way the footwear ended up mounted on the backing plate. The 1940 brake footwear pivoted on a pin at the bottom and wherever actuated by a slave cylinder at the top rated. This style is regarded as “single top shoe” or “top and trailing shoe brakes”. When brake drive is utilized, both equally footwear pivot at the bottom attachment bolt and press against the drum with equal tension. Shoe get in touch with tended to remain in one particular place and the dress in was uneven. Pedal energy was significant for the reason that none of the rotational drive was utilized to assist make the footwear press more durable to the drum surface.

Living with the 1939 Ford brakes

To enhance shoe to drum get in touch with, the 1940 style utilized a pair of cams on the shoe pivots that moved each and every shoe in or out to get rid of significant spots. Possibly lock nuts on the backing plate aspect of the brakes, or spring stress bolts allowed for adjustments to be designed.

These spring tensioned bolt adjusters have a tendency to resist staying in area, and the condition is even much more aggravated if you chemically thoroughly clean the backing plates for portray. Rust tended to build a resistance to turning of these spring bolts. The reduce cam bolts on the style on the right tended to loosen as well, so when employing the early Ford brakes periodic inspection is a will have to for ideal performance. Over-all the style works well but needs maintenance.

A phrase about brake shoe grinding:

Brake grinding was frequent again in the day, as everyone was well mindful that a little asbestos dust hardly ever harm anybody! Perhaps no one particular imagined of the downside of grinding off of precious braking content was a problem either. If the brakes wherever not ground down, they would inevitably dress in to the condition of the drums, but prior to that taking place, the 1939 brakes experienced a horrible habit of grabbing and significant recognizing. This brought on wheel lock at inopportune moments, along with unpredictable braking. These options and cons make the variety of the F100 truck brakes an uncomplicated preference.

Ford F100 pickup truck brake style

The F100 brakes are what is termed a “Duo-Servo” style. This style works outperforms the 1939 top edge style for the reason that it works by using the rotation of the drums to result in the brake footwear to “twist” and press against the drum lining a lot more durable. So a lot superior in reality that they involve considerably less pedal energy and are considerably less delicate to significant recognizing. This also has the profit of a much more even brake shoe dress in and more time shoe lifestyle. Let’s appear nearer at why the “Duo-Servo” style works so a lot superior than the 1939 style.

At to start with glance the F100 style looks a lot like the 1940 style, but on nearer examination we see that the footwear are not mounted on a stationary pivot place, but rather “floating” on a pin and spring assembly. The floating function lets the brake footwear to twist and wedge them selves against the drum rising braking friction. By means of this servo action the footwear transmit movement to each and every other, rather than just one particular lead shoe carrying out all the work.

Through the 1950’s there was a revolution of types on brake improvement. Some of the more substantial much more prestigious vehicles arrived outfitted with this current style. The major distinction was that the footwear now “floated” on the backing plates and took benefit of the rotation of the drum to grip more durable. Ford acknowledged the benefit this would have on the heavier truck they produced during the early 1950’s. The place not lost on performance lovers. Even while the early brake drums ended up 12 inches in diameter, the 11 inch F100 and F1 style was much exceptional in performance.

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